Friday, December 22, 2006

CES International 2007

I finally booked my flight and hotel this week for the CES show in Las Vegas, which runs from Jan. 8th to the 11th. I found another cheap rathole about a mile from the strip. I plan to spend a lot of time at "The Show" where all the high end audio products are showcased. I'll also try to spend some time at the HTPC related vendor's booths, like Microsoft (so I can voice a few of my complaints/concerns with Vista), NVidia, etc.

I'll take my digital camera so I can take pictures of anything interesting to share on my blog. Let me know if you are planning to attend and would like to meet with me to talk about my products or business plans. I'm going to try to attend the AVS Forum CES 2007 Party. Hopefully I can meet some of you there.

Tuesday, December 19, 2006

Blogger Broken?

It looks like a lot of people using Blogger or Blogger beta (myself included) have reported a problem with their blogs. As you can see, if this hasn't been fixed, the left column has been squeezed to the left.

Hopefully, the Blogger support staff will come up with a fix real soon.

Monday, December 18, 2006

Another Tune for the Holidays

This weeks SongSpot is a really nice song from Rick Cutler called "Gloria" from his album 'Sanctuaries'. In his bio, it says Rick studied both at the Julliard School as well as with jazz great Chick Corea. I'm a big Chick Corea fan, so that was enough to convince me to pick Rick's song as this weeks tune. Besides, I feel sorry for anyone who has to tour with Liza Minnelli. Actually, it's probably one of the more entertaining jobs in show business, but I still think she's a bit of a freak.

Monday, December 11, 2006

Tis the Season

This week's SongSpot is another tune to help get us in the mode for the holidays. I'm probably driving my family nuts with all the holiday music in our house, so I thought I'd share some with the rest of this small little blogworld, blogosphere, or whatever you want to call it.

This week's tune is from a Boston trio called Siúcra (pronounced shoo-kruh). The name of this song is 'Christmas Day, Christmas Night' and it is on their album "A Very Siúcra Christmas."

Wednesday, December 06, 2006

Does Portable Music Have to be Compressed?

There's a post over on Slashdot linking to an article at The Christian Science Monitor about portable music players and compromised sound quality. This is certainly a concern of ours. Many people probably can't really hear the difference between a lossy compressed audio track and a losslessly compressed audio track when listening with their portable music player. And most of the major online music distribution services like iTunes offer only lossy compressed audio probably because the majority of their customers are iPod owners and it is faster and easier to download these smaller files.

The article also mentions a study by the Consumer Electronics Association (CEA) that showed 56% of consumers have never heard what they would consider a 'great audio experience' and therefore don't even know how to evaluate audio quality. I don't know if this is discouraging or if I should be encouraged by the potential untapped market.

However, if the music industry eventually replaces all of the packaged uncompressed audio currently available on optical disc with downloadable lossy compressed audio tracks, then those of us with higher quality audio systems might suffer.

I don't think this will happen. I've mentioned in earlier posts that there other online sources who offer downloads of uncompressed or losslessly compressed audio like Magnatunes and MusicGiants. We may have to pay a little more for these higher quality formats, but I think it is worth it. It will be interesting to see if the larger online music stores ever offer high quality audio or if it just becomes another niche market. However, with the Internet and worldwide distribution, niche markets can do pretty well because of the long tail effect.

Monday, December 04, 2006

When Rain Turns Into Snow

This week's SongSpot is from Alastair Moock's song 'When Rain Turns Into Snow' from his album Walking Sounds.

Suddenly the weather really cooled down here in Wisconsin. A little over a week ago, we were hitting fairly comfortable temperatures (over 60°F/15.5°C) for this time of year. Now we are only hitting daytime highs of about 28°F/-2°C. Sweater weather to full-on Winter coats. Oh well, our family really likes to play in the snow and now we have a couple inches. Hopefully it will last and accumulate.

This song uses the phrase "love turns into memories when rain turns into snow" to express the rather depressing feeling when falling out of love. So it really doesn't fit the happy feelings we have with the onset of Winter and the switch from the cold, wet, and sloppy rain into beautiful, graceful and playful snow.

Monday, November 27, 2006

Who is Amplio Audio?

Here's an excerpt from our business plan that might help to explain who we are and what we are trying to do. This is basically the executive summary.

Amplio Audio is a startup business in the HTPC (Home Theater Personal Computer) industry with an exclusive focus on the audio component of the Home Theater experience. Our target customers are audio/video enthusiasts who use their personal computers (PCs) to play music, watch live TV, movies, and other video content as well as to control and manage their media libraries. Amplio’s products provide our customers the best possible audio for their media systems through a direct digital interface to their audio data complemented by a world-class amplifier system and speaker interface. Amplio’s products are designed to compete with the high end of their target market while selling for significantly less than current offerings.

Amplio Audio is actively developing prototype products. A conceptual prototype was completed in March, 2006. This is the first device to integrate audiophile quality amplification in a single, user configurable package compatible with Windows or Macintosh computers. This prototype was built using Amplio-designed circuitry that connects audiophile quality amplifiers to a commercial interface unit. Amplio is now developing a working prototype including a customized interface unit, improved application software and consumer-oriented packaging.

Amplio Audio fills a growing market niche, providing audiophile quality components that interface with consumer’s Windows or Macintosh PCs and their home entertainment systems. This market is currently served with a combination of products from several manufacturers, none of which are designed specifically for home theater applications. Amplio’s product combines the functionality of a soundcard, home theater receiver and amplifier into a single device, providing consumers with an affordable, audiophile quality listening experience.

This week's SongSpot from the Tadpoles

This week's SongSpot is called 'Ride the World Around the Sun' by the Hoboken, NJ based Tadpoles. It's from their second album Far Out, which received a four-star review in Rolling Stone.

The Tadpoles formed during the early '90s. Since then, the psychedelically-influenced band has evolved into a steady lineup of vocalist and guitarist Todd Parker, guitarist and vocalist Nick Kramer, bassist David Max, and drummer Adam Boyette. The band has founded its own record label, Bakery Records, to self release three studio albums produced by former Shimmy-Disc founder Kramer as well as an EP and live album.

A well-received appearance at the 1997 Terrastock Festival sponsored by the U.K. magazine Ptolemaic Terrascope has consolidated a national following for the band.

Wednesday, November 22, 2006

Interview with Seagate's CEO about storage technology and content distribution

Lately, I've been too busy working on project planning and development to post to this blog. This afternoon I took a little break to scan through my RSS reader (I use Google Reader) to catch up on the latest news. Every so often I like to post links to interesting articles, like the 'All About Sound' series posted over at the Audio DesignLine website. Today, I came across an interesting interview with Bill Watkins, who is the CEO of hard disk manufacturer Seagate.

During an interview with Robert Scoble, Bill talks about their company's business opportunities with regard to media storage and content distribution. Some interesting comments regarding physical distribution technology like Blu-ray and HD-DVD.

Monday, November 20, 2006

Thanksgiving SongSpot

This week, we celebrate Thanksgiving so I searched Sonific's site for a song that might be appropriate for the occasion. Here's what I found:

The first song that came up - 'Thanksgiving Day', by The Kelly Bowlin Band, wasn't chosen because it is a ripoff of a very familiar tune (can anyone guess which one I'm referring to?). The next song, 'Thanksgiving', by Stanton Lanier, is a nice new age tune, but not quite what I was looking for. Next on the list is 'Thanksgiving (No Way Out)' by the Violent Femmes. I was tempted to pick this, because the Femmes are from my home state of Wisconsin (they're from the Milwaukee area), but this tune just doesn't capture the Thanksgiving spirit, if you know what I mean. Next came 'Thanksgiving with a Prostitute', by Lonesome Steve and the Coyotes, close but maybe not real appropriate. The next song, 'Happy Thanksgiving', by Debbie Friedman, is probably the one that I should choose because it is the least offensive, but it just didn't appeal to me either. It reminds me of the songs that we listened to with our kids when they were toddlers. The last song that appeared in the search results is called 'David's Thanksgiving & Prayers (Thine O Lord)', by Faith A. Davis. I almost didn't even listen to this because I'm not really into religious tunes. I decided to listen only because I couldn't decide between any of the others on the list and was surprised to hear a really good song. Like i said, I'm not a big fan of gospel music, but have to admit the vocalists are pretty amazing.

I didn't really find my perfect Thanksgiving song, but the best of these choices is probably the gospel tune from Faith A. Davis. Again, it's called 'David's Thanksgiving & Prayers (Thine O Lord)' from her album Worship... It's a Lifestyle.

Thursday, November 16, 2006

Choosing the DAC, Part 2 -- Narrowing it Down

We're still trying to pick the best DAC (digital to analog converter) for our product. We've looked at all the data sheets and compared the specs and test results. There are hundreds of DACs from several manufacturers to choose from. Using the specs, we were able to identify what we think are the best products on the market. Since we want to support playback of all currently known audio formats (at least those that you can play using an HTPC, which means no SACD because Sony/Philips will not license the necessary hardware and software for playing SACD with a PC), we will need to use a DAC that has a sampling rate of up to 192 kHz and bit depth of at least 24 bits. For our application, we would also like to use DACs with fully differential outputs because of the benefits of eliminating noise from the signal path and the fact that our amp modules work best with a differential input. That narrows our choice down a little bit.

The three key parameters that we looked at for evaluating different DACs were the signal-to-noise ratio (SNR), dynamic range (DR) and total harmonic distortion (THD+N). Based on the three main criteria, we decided to limit our final choice to a DAC with a SNR and DR of at least 120 dB, and a THD+N of at least -100 dB. Here’s a list of DACs that meet our specifications:

Manufacturer

Part #

SNR

DR (dB)

THD+N (dB)

AKM Semiconductor

AK4396

120

120

-100

Cirrus Logic

CS4398

120

120

-107

TI/Burr Brown

PCM1792

132

129

-108

Analog Devices

AD1955

120

120

-110


We've also tried to contact a representative of these highly respected manufacturers, Texas Instruments/Burr Brown, Cirrus Logic, Analog Devices, and AKM Semiconductor, for advice. So far the only ones to respond have been Richard Kulavik, Manager of Marketing and Applications at AKM and John Melanson of Cirrus Logic. TI/Burr Brown, and Analog Devices have yet to respond. Could it be that Amplio is just too small and insignificant? Maybe -- that's one of the challenges and frustrations of being a start-up.

Wednesday, November 15, 2006

Choosing the DAC, Part 1 -- Basic Theory

When we talk about digital to analog conversion in our application, we are referring to converting PCM (pulse-code modulation) data into an analog signal. This resulting analog signal can either be represented as an electrical voltage or current. So, for a voltage output, a number is the input and a voltage is the output. These numbers are updated at the sampling interval (or sampling rate) of x times per second. For example, CD data is represented with a 16-bit number at a sampling rate of 44,100 times per second. So a 16-bit number, which represents the amplitude of the audio at a point in time is sent to the DAC (digital to analog converter), along with a clock signal, which causes each number to be stored with the correct sequence and timing (lets ignore that relatively important detail for now). Then the output voltage changes very rapidly from the previous value to the value represented by the currently stored number. So basically, the voltage (or current) is set and held in time until the next number is set. What you end up with is a bunch of rectangular pulses that look like the red line shown in the graph below, instead of the smooth gray lines which represent the ideal analog signal.

The differences between the red stair steps and the smooth waveform create a type of distortion in the signal called aliasing. According to good ole Harry Nyquist, the aliasing distortion can be avoided if the sampling frequency is two times greater than the bandwidth of the maximum frequency of your signal. That may not make a lot of sense, so let me use CD audio in another example. Many experts believe the frequency range of human hearing is between 20 and 20,000 Hz. For the majority of us, we can’t hear any sounds above or below that range. So, if you apply the Nyquist sampling theorem (actually Vladimir Kotelnikov and Claude Shannon deserve some mention here, but our friend Harry seems to get all the credit) and double the upper range, we get a sampling rate of 40,000 Hz. So to avoid the aliasing distortion, 44,100 Hz was selected as the sampling frequency for audio CDs.

Monday, November 13, 2006

Welcome to the End

Nice blog post title... I bet some of you thought I was announcing the end of Ampliozone. I'm not. I hope to keep this going for a long time. Actually, this week's SongSpot is a song called 'Welcome to the End' off the album The Universe is Expanding from the synth-pop band Anything Box. The group was formed in New Jersey in 1986 by Claude S. with his friends Dania Morales and Paul Rijnders. Their name comes from the title of a book of short stories. A lot of their work is described as soothing and melodic. One of their albums, Worth, is described as the best album Anything Box ever made, but unfortunately was never released commercially. However, it looks like you can buy it at CD Baby.

Thursday, November 09, 2006

All About Sound, Part 12

This is it. The final installment in the introduction to sound technology from Scott Janus' book "Audio in the 21st Century" (courtesy of Audio DesignLine).

In Part 12 he writes about Measuring Sound Quality, Harmonic Distortion, Total Harmonic Distortion, and Signal to Noise Ratio. I'll probably want to cover some of these topics in a little more detail in future posts and discuss how these measurements are applied to the technology in our products.

I hope you enjoyed this series.

Monday, November 06, 2006

All About Sound, Part 11

The introduction to sound technology from Scott Janus' book "Audio in the 21st Century" (courtesy of Audio DesignLine) continues.

In Part 11 we learn more about Sine Waves, Triangular Waves, Square Waves, and Sawtooth Waves..

SongSpot for Elections

Tomorrow is election day here, so I chose a song that might inspire people to go out and vote (or not). This weeks SongSpot is called 'Breaking Through' from the album Long Way from Tomorrow by the band Small Change Romeos.

Thursday, November 02, 2006

CES 2007

Are you going to the Consumer Electronics Show in Vegas this year?

I was planning to go, but I can't find a reasonably priced room somewhere near the strip. I attended CES 2006, but had to stay at the Howard Johnson's near the airport. It was cheap, but not necessarily the greatest accommodations. Given that we are a startup with no income, cheap is very good. Anyhow, even the HoJos is all booked up from January 7th to the 11th, 2007. I'd also like to find something a little closer, so I don't have to rent a car.

So, if you know of any alternatives, please let me know.

All About Sound, Part 10

More audio theory...

Part 10 from Scott Janus' book "Audio in the 21st Century" courtesy of Audio DesignLine introduces us to the frequency domain.

Wednesday, November 01, 2006

All About Sound, Parts 8 and 9

There's more!! Part 8 from Scott Janus' book "Audio in the 21st Century" courtesy of Audio DesignLine continues to cover sound pressure and intensity. Part 9 uses a few examples to explain sound pressure and decibels in more detail.

Tuesday, October 31, 2006

Do they know it's Hallowe'en?

Check out this video:



This single features a star-studded ensemble (Beck, Sum 41, The Arcade Fire) known as the NORTH AMERICAN HALLOWEEN PREVENTION INITIATIVE. Both a trick and a treat, this song is a satire - as well as a charity-benefit song with all proceeds being donated to UNICEF.

Monday, October 30, 2006

YouTube Removes Comedy Central Clips Due to DMCA

Read this on Slashdot:

Today, YouTube removed all of its Comedy Central content. Google knew this was coming but you have to wonder if YouTube will be worth that $1.65 billion on Monday. The take down request comes a year after a Wired interview where Daily Show Executive Ben Karlin encouraged viewers to download: "If people want to take the show in various forms, I'd say go."


Now the video clip in one of my earlier posts about damn spammers doesn't play. Oh well. It was pretty humorous. Sorry if you missed it.

Halloween SongSpot

Halloween is tomorrow, so this week's SongSpot is from the band Erplosis Daet and it is called "Scary Halloween Monsters" from their album 'A Skip In The Brain'.

Thursday, October 26, 2006

All About Sound, Part 7

Another installment!! This is the latest installment of Scott Janus' "Audio in the 21st Century" from Audio DesignLine. Part 7 talks about measuring sound intensity and power.

In this article, he covers the basic math computations using the logarithmic scale and decibels. He briefly mentions that human hearing is not linear -- we can hear slight changes at low levels, but don't notice similar differences at high volumes. I think he plans to discuss this topic in more detail in a later installment.

In case he doesn't mention this... I thought I would go ahead and offer a little more detail. As mentioned in earlier installments, sound is created when something strikes another object. So when a guitar string vibrates, it is striking against air molecules. The vibrations cause the air nearby to compress and expand. A shorter string vibrates at a faster rate than a longer string, creating a higher pitched sound... The more compressed (or expanded), the more energy it contains and can expend. The loudness, or intensity of the sound is measured in terms of the amount of energy passing each second through one square centimeter of area. Energy expended over time is power and the unit is the watt. A watt is one joule per second. As you know, a 75 watt light bulb is pretty bright. A 40 watt bulb, not so bright. One of those small little night lights used to find the bathroom without bumping into a wall is probably around 1/4 watt. The amount of power found in sound is really small. The amount of power carried by ordinary conversational sound is about 1/1000 watt.

The human ear detects the difference in loudness by ratios of the power, not the actual differences. So, a 2000 microwatt (1/2000 watt) sound will seem louder than a 1000 microwatt sound, but a 3000 microwatt sound will not seem to sound louder by as much again. It actually takes a 4000 microwatt sound to seem louder by as much as a 2000 microwatt sound compares to a 1000 microwatt sound. To get a sound that is as much louder again than a 4000 microwatt sound, we would need an 8000 microwatt sound. The rations 2000/1000, 4000/2000, and 8000/4000 are all equal even though the difference are not, and it is the ratios that the ear detects.

This is where he explains that we don't hear linearly, but on a logarithmic scale. When one sound carries 10 times the power of a second sound, the ratio of the first to the second is 10 and the log (base 10) of this is 1. The difference in sound power is then said to be one 'Bel'. If a sound is 100 times more powerful than another sound, it is two Bels louder, 1000 times would be 3 Bels, etc. Since the Bel is too large of a scale for practical use, we use the decibel, which is 1/10th a Bel. A sound is a decibel louder than another when the first is 1.26 times as powerful as the second -- log(1.26) is about equal to 0.10.

The decibel is used one of two ways:
  1. to measure power or intensity
  2. to measure amplitude
The equation used to to measure sound power is (10 * log(N1/N2)). To measure sound amplitude we use the equation (20 * log(N1/N2)). So, a sound that is 10 times louder than a second sound (20 * log(10/1)) = 20 decibels. A sound that is twice as loud (20 * log(2/1)) = 6.02 decibels.

When dealing with these ratios, they use a standard reference for the denominator. For sound power or intensity, the denominator is the threshold of hearing (about the sound of a mosquito flying about 3 meters away), which is about 10-12 watts/m2. Sound pressure level (SPL) is usually used to specify the sound intensity. The upper limit of sound, before it behaves like a shock wave is about 194 dB (SPL). For comparison, windows break at about 163 dB; the sound of a jet engine from 30 meters (100 feet) is about 150 dB; the threshold of pain is about 130 dB; the sound of a train horn from 1 meter is about 120 dB and at this level can cause immediate perforation of your ear drum (so don't stand too close to a train when the horn goes off); and, loud music in a dance club is probably at 100 dB. They say anything above 85 dB is considered harmful and over 95 dB for long periods is considered unsafe.

BTW, so far, no one has entered the contest. I wonder why...? Is it the award -- no one likes beer or cheese? If so, any recommendations for a more enticing award? Is it because no one likes taking tests? Oh come on, it should be easy. All you have to do is read the articles. Is it because no one is reading those articles? (I know, I know, not many people are even reading this blog, so I'd really like to come up with useful info that potential readers find interesting). I'd really like some feedback on this. If there is a response, I might go ahead and post another test covering the later installments and award the winner with something like a gift certificate from Amazon.

Tuesday, October 24, 2006

Testing 1, 2, 3... (Parts 1 - 4)

Okay, I've decided to post the sound test after all. Actually this only covers the first 4 parts and depending how this goes, I may post another one covering later installments. I'm really curious to see how many people are actually reading those articles. The person with the highest score will win a prize. If more than one person has the highest score, I will put their names in a hat and draw a winner. The winner will get to choose between a six-pack of Wisconsin micro-brewed beer or a pound of premium award winning Wisconsin cheese (or maybe I could be convinced to substitute something of equal value). At the end of the test, we have instructions for submitting your answers.

Here's the test:

  1. True or False, sound requires a medium through which to propagate; sound does not travel through a vacuum.
  2. True or false, the speed of sound is faster at lower temperatures.
  3. Airborne sound travels in the form of:
    1. Latitudinal waves
    2. Awesome waves
    3. Transverse waves
    4. Longitudinal waves
    5. Attitudinal waves
  4. In the early evening when the air closer to the ground is still warm and the air higher in the sky is cool, sound waves will:
    1. Bend downward
    2. Continue moving straight
    3. Bend upward
    4. Reflect off the cooler air
  5. True or False, sound waves consist of alternating regions of compression (increased pressure) and rarefaction (decreased pressure). There is also an ambient pressure before the wave propagates.
  6. True or False, a pure tone is a sound with sinusoidal time fluctuations.


  7. The above figure represents a pure tone waveform. True or False, a period (T) is the time it takes for the wave to go from the highest amplitude to the lowest amplitude.
  8. True or false, in general, all sounds move at the same speed within the same medium.
  9. Given a pure tone with a period of 1 ms, what is the frequency of the tone?
  10. If a tree falls in the forest, does it make a sound?
  11. True or false, phase can be used to compare the alignment of two tones of the same frequency. This difference between two tones is known as a phase offset or phase difference. Phase offset is also loosely referred to as simply phase.
  12. Two pure tones with a frequency of 1000 hertz are 90 degrees out of phase. What is their phase offset in units of time?
  13. What is a convenient way to diagram how sound moves?
    1. Bubble diagrams
    2. Wave fronts
    3. Sound rays
    4. Both a and c
    5. Both b and c
  14. Since c (speed of sound) = f (frequency) multiplied times λ (wavelength); what is the wavelength of a pure tone with a frequency of 1500 hertz at STP (standard temperature and pressure)?
  15. True or false, the angles a sound wave hits and reflects off a smooth surface are the same.
  16. When two waves have a non-zero phase offset, they are said to be in phase. When two waves have zero phase offset, they are out of phase.
  17. True or false, when a sound wave refracts through another material with a higher speed of sound, the wavelength of the sound wave will decrease.
  18. True or false, the frequency (f) is the rate at which the wave repeats (cycles per second, called hertz).


To qualify for entry into this "contest", you must leave a comment to this post with some way to identify yourself -- maybe leave a nickname and your location. DO NOT INCLUDE YOUR ANSWERS IN YOUR COMMENT. Then submit your answers to soundtest1@amplioaudio.com. Be sure to include the same nickname identified in the exam's comments. The winner will be announced next Tuesday (Halloween), so you can submit answers until Monday night, which is October 30th.

All About Sound, Part 6

There's more!! They should just post the whole darn book. Here's the latest installment of Scott Janus' "Audio in the 21st Century" from Audio DesignLine. Part 6 discusses the doppler effect.

I think I'm going to postpone the test because I'd like to post it after all installments are posted at DesignLine. BTW, the highest score will get their choice of either a six-pack of wonderful Wisconsin micro-brewed beer or a block of premium cheese.

Monday, October 23, 2006

All About Sound, Part 5

Another installment of Scott Janus' "Audio in the 21st Century" from Audio DesignLine.

Part 5 is getting a little more technical, so pay attention. Oh, and don't forget about tomorrow's test.

New SongSpot from Roxword

This weeks selection for our SongSpot is from Roxword. He's an old friend of mine and his real name is Steve Roxborough. Steve is a poet who lives in the state of Washington in a small town on an island on Puget Sound. We were college teammates and roommates (along with 6 other guys) many years ago. Steve brings us the latest in spoken word featuring a variety of musical and intellectual directions, moving seamlessly from R&B to jazz to rock to classical to soundscape to new age to music beyond category, all expertly punctuated with mind-bending poetry. This song is named 'Another Roadside Attraction' and is from his album Spiritual Demons.

Friday, October 20, 2006

Open Architecture

In previous posts I've mentioned that we'd really like to design a product that has the modularity and flexibility of the personal computer. Not the closed or proprietary architecture of the Mac, but the open architecture of the PC. Then people could choose the amp modules, power supplies, case, audio interface (soundcard), etc., that would meet their needs for number of channels, sound quality and budget.

From Wikipedia:

"Open architecture is a type of computer architecture that allows users to upgrade their hardware in all of the computer hardware & components (for example the IBM PC had an open architecture). This is the opposite of a closed architecture, where the hardware manufacturer chooses the components, and they are not generally upgradable (for example the Amiga 500 home computer had a closed architecture).

Open architecture allows potential users to see inside all or parts of the architecture without any proprietary constraints. Typically, an open architecture publishes all or parts of its architecture that the developer or integrator wants to share. The open business processes involved with an open architecture may require some license agreements between entities sharing the architecture information."

I'm not sure if we will ever be able to do this, but it is something I am interested in achieving. I think there is great potential here. It may even turn part of the consumer electronics industry upside down or inside out. Of course, this may not appeal to the ultra expensive, high end, "audiophile" producers and consumers, but I think it would really be great for the rest of us.

What do you think? As a consumer, would you like to purchase a system that could be expanded from 2 channels to 8 channels? Or upgrade the DACs or amplifier modules when a new generation is released? Be able to choose from a variety of case manufacturers to have one that best fits your style?

If there are any reps from manufacturers of amplifier modules, power supplies (the best technology for this would be switching power supplies or SMPS), or sound cards reading this, I'd love to hear what you think about this idea? Do you think it would expand your market, or not? Do you think the technical hurdles for designing your components to meet a specific form factor and use of standard connectors would be too limiting? Maybe someone like Creative would offer a version of their X-Fi that would be compatible -- and like the "Intel Inside" promo, they could have "X-Fi" inside. Of course, we could also have "UCD powered", etc.

Dual core, quad core processors hit a snag?

Sander Sassen writes that without optimized code they're useless for the time being, much like 64-bit support.

Wednesday, October 18, 2006

All About Sound, Parts 2, 3 and 4

Here are Part 2, Part 3, and Part 4 in the series about sound theory from the Audio DesignLine Website. These are also excerpted from Scott Janus' book "Audio in the 21st Century." There will be a test next Tuesday. ;^) I'd like to thank Scott Janus for allowing Henry Davis and the folks at Audio DesignLine for posting these articles. And of course thanks to Henry for his work as well.

Tuesday, October 17, 2006

What is Sound?, Pt. 1

On the column to the right, we have a links section that includes the Audio DesignLine website, where you can find all sorts of interesting information about audio news, engineering and theory. They currently have a series of articles about sound that I thought some of you might find interesting. Here's the first part, which is an excerpt from Scott Janus' book "Audio in the 21st Century."

Monday, October 16, 2006

SongSpotting - Your Own Blog Radio

I read about SongSpots last Friday in Wired's Listening Post. So today I thought I would try it out. Well it's not quite your own private radio station for your blog. Unfortunately, you can only play one song, instead of a playlist. In our case this isn't really a problem because most of our readers probably don't come here to hang out and listen to music. The other problem is that since we're not familiar with most of the artists, we don't have a chance to help promote artists we really like. However, this is a good opportunity to discover new music. It would be great if we could use a similar type of blog widget with NPR's All Songs Considered, which is also a really good way to learn about new music. Just to keep it interesting, we'll probably update the player with a new song/artist about once a week. If you scroll down the right side of ampliozone, you will find the player just below our blogroll. The first selection is a song called "Mission" from the Album "Individuation" by Thomas Marriott. It's described as "straight ahead jazz music with a modern twist." Let us know what you think.

Friday, October 13, 2006

Google Adds UW-Madison and Wisconsin Historical Society Library collections to its Library Project.

I'm a graduate of the University of Wisconsin-Madison, so I was excited to hear Google has added the entire collection of public domain historical resources from the UW-Madison and the Wisconsin Historical Society Library to its Google Books Library Project. Maybe excited isn't exactly the right word, but I still think this is a pretty cool project and I'm proud of my alma mater for contributing.

BTW, the UW-Madison and Wisconsin Historical Society historical document and book collection, at 7.2 million holdings, is one of the largest collections in the United States, ranked 11th in North America. I doubt this is included in this project, but an interesting side note about UW-Madison/WHS, is they co-sponsor the Wisconsin Center for Film and Theater Research. The WCFTR is one of the largest archives of entertainment industry research material in the world.

The University of Wisconsin-Madison joins the impressive list of project partners that includes the University of California, University of Michigan, Harvard University, Stanford University, the New York Public Library, Oxford University and the Universidad Complutense de Madrid.

Thursday, October 12, 2006

Changing Blog Title and Colors

I finally figured out how to put an image in the title's background. The image is a photograph Warren took of a sunset over Lake Monona near his home on the near east side of Madison, Wisconsin.

After inserting the image, I wasn't very happy with the way it looked next to the rest of the blog's colors. So for the past few days I've experimented with different color options. I think I've finally made up my mind. Still not entirely happy, but we'll leave it like this for a while until we get bored with it or unless some people tell us these colors are making them ill.

AMD LIVE! Media Center PCs

In addition to Intel's Viiv PCs, AMD is also promoting HTPC solutions using AMD technology. An AMD LIVE! Media Center PC includes an AMD Athlon™ 64 X2 dual-core processor, Cool'n'Quiet™ technology, etc., with "small size and innovative designs to fit different lifestyles." eHomeUpgrade recently posted an article announcing new PCs from Dell and Alienware based on the AMD LIVE! platform.

Tuesday, October 10, 2006

Restaurant owner says songs may cost him his business

There's an article today in Techdirt about a restaurant that may close down because it can't afford to pay the fines after a local band played a few cover songs without the restaurant having paid the necessary license fees. I realize that the original artist and songwriter deserve to get paid for their work, but isn't this a little ridiculous? I wonder why they are suing the restaurant and not the band. And, why didn't the band pay the necessary fees so they can perform other artist's music?

Sunday, October 08, 2006

CD Costs

I found this pie chart in a David Byrne blog post showing how the costs are distributed for a CD sold at retail.
I've heard that the artist only makes about 10% of the CD sale price, but wasn't sure how the rest of it broke down. This also shows the distribution based on a $15.99 retail price. I wonder what it would look like for discounted CDs. I would assume the retailers take the hit there. It's also not clear to me how many companies, organizations or whatever are taking a piece of the pie. Do the labels get the label overhead, marketing/promotion, label profit, distribution and packaging/manufacturing? If so, they end up with 55%. The retailers are getting 31%. Granted, a much smaller percentage is actual profit. Anyhow, I could see how an artist might benefit from alternative promotion and distribution methods like doing it themselves or working with one of the new breed of record labels like Nettwerk Music Group, Nonesuch Records or Magnatunes. I also like the name for the organization that is the source for this pie chart - the Almighty Institute of Music Retail.

Friday, October 06, 2006

Damn Spammers

I think some spammer has hijacked our domain name this past week. I registered the domain name through Yahoo! Small Business. As you can probably tell from our website at www.amplioaudio.com, we decided on the low-budget deal. All I wanted was the domain name and a few email addresses with @amplioaudio.com. Actually, I wanted www.amplio.com, but that domain name was taken even though nobody seems to be using it. So the amplioaudio website is really just a placeholder until we get closer to selling our products.

During the last week or so, I've been getting lots of "undeliverable mail" messages, saying the message from 'someweirdname at amplioaudio dot com' could not be delivered, etc. Each message has some different email name like 'nzogo at amplioaudio dot com'. None of them are accounts I set up with Yahoo!'s mail service. A lot of the undeliverable messages show that the messages were trapped by some spam filter. Obviously, some spammer is sending out thousands of messages using the amplioaudio domain. Now lots of people will probably block amplioaudio and legit messages will all get dumped in their spam folders. This pisses me off!! Does anyone know if there is any way to stop this? I contacted Yahoo!'s tech support several times, but they haven't responded. Any ideas???

Sony seems to be fine with digital downloads

An article just posted in Arstechnica, reports that a Sony exec expects digital downloads to be the most common distribution method for games in about five years when Blu-ray will just be coming a house hold word. This is when he expects everyone to have a fast enough Internet connection. The exec is really just talking about how this will apply to the gaming industry, but obviously this will have an impact on movie and music downloads. Most of the major online services only offer compressed audio, but with fat pipes they will be able to sell uncompressed, higher res, multichannel music.

The article also mentions that in some areas the download speeds are already there. Like those lucky bastards who currently have Verizon's 30 Mbps Fios service or even 100 Mbps from a Swedish cable modem service. I wish we had something like that here in Madison. I think my AT&T 6 Mbps DSL service is the best we can do here.

Thursday, October 05, 2006

AES 121st Convention

I'm not at this years AES convention in San Francisco. Can't afford to go, but maybe next year. For those of you who may not be familiar with this convention, the AES (Audio Engineering Society) convention is usually a little more technical than something like the Consumer Electronics Show (CES) and is obviously focused on audio engineering and a lot of this is geared to pro-audio.

If anyone reading this blog is at the show or planning to attend in the next few days, feel free to contact us and share any interesting information. I'd really like to hear about these workshops:
SURROUND SOUND–NOW & IN FUTURE
HIGH RESOLUTION AUDIO — DISCS VS. DOWNLOADS
CONTENT PROTECTION AND AUDIO DISTRIBUTION: CAN THIS MARRIAGE BE SAVED?
WHY THE ROOM IMPULSE RESPONSE AFFECTS EVERYTHING WE HEAR: What Is It; Why Does It Matter, and How Do We Measure It?
HUMAN FACTORS IN THE DESIGN OF AUDIO PRODUCTS AND SYSTEMS
THE HOWS AND WHYS OF DELTA SIGMA PROCESSING

And, of course I would like to spend some time in the exhibit hall. If you are an exhibitor, please free to enter any comments below.

Since I can't attend this year's convention, I'll do the next best thing and try to read a bunch of blog entries covering the show. I've searched for 'AES blog' and only come up with these so far:

Professional A/V Industry Blog
Mix Online
Brian's Brain
Peter at WordPress
John Atwood (ClariSonus)
Anablog (note: I discovered this blog on 10/31/06)

If I come across any others I will add them to this list. 10/6/06 update - okay, Brian Dipert (click on Brian's Brain blog, which I just added to the list) is at the AES convention. Hopefully, he will post something about the convention in the next few days. Another update: just found a few more, I'll just add them to the list.

Wednesday, October 04, 2006

IDC Forecasts Growth for the Media Center PC Market, But Remains Cautious About Mainstream Adoption

IDC is one of those market research firms that startups like Amplio Audio should use to figure out the size of their market. I have no idea what it would cost to get one of these companies to do a detailed analysis, but one of their general reports (these are not necessary product specific) costs thousands of dollars. The price tag for the full report from which this article is based is $4,500. As much as we could use detailed market data and know how important it is for our biz plan, we've decided to invest in our technical development. Maybe I will talk more about our market analysis in a future post...

Anyhow, here's an IDC report that talks about the growing popularity of HTPCs or what they call Media Center PCs. Click on this link to read the full article.

Tuesday, September 26, 2006

Intel's "stylish and small" $1 million Challenge

Intel announced the Intel® Core™ Processor Challenge at their Fall Intel Developer Forum, as a PC system design challenge which they hope will speed up the availability of small, stylish PCs for consumers' homes.

Eligible entries will be judged based on attributes of style, acoustics, functionality and features. Taken straight from their press release linked above, "Intel will award the Grand prize winner with up to US $300,000 for hard tooling costs of their winning design and US $400,000 for co-marketing activities with Intel promoting the design. The first place winner will receive up to $300,000 for hard tooling of their winning design."

I wonder if PC Alchemy will enter the contest? This is their stylish and small PC called the MiniMCE. I also like the stylish design of Apple's Mac mini, but I don't think it's eligible because even though it uses the Intel Core Duo processor, it's not a Intel® Viiv™ technology-based PC.

Let me know if you come across other potential entries. It will be fun to see if some creative designs help to launch some truly new and innovative companies.

Update - 9/27/06, here's a pic of another small form factor HTPC, which I think is from a German company, found after performing a Google image search:

Saturday, September 23, 2006

FLACs from Philadelphia Orchestra

The Lossless Audio Blog reported today that the Philadelphia Orchestra launched a new online music store and will be selling recordings of their concerts. The cool thing about this is, in addition to offering downloads in the popular MP3 file format, they will also offer them in the lossless FLAC (free lossless audio codec) format. Great news for classical music fans! Check it out.

Friday, September 22, 2006

What's the USE?

As an engineer, I have always focused on the functionality of a product with little attention left for the appearance. This is the old 'function determines form' attitude in spades.

It is easy to take the human out of the function equation, to define function in terms of a set of specifications that can be reduced to numbers. If you hit the numbers, the function is there; if you don't, it's back to the drawing board (or the unemployment office).

But a good design isn't just a set of numbers; the thing being designed is something that people will use. The starting point for a good design is an understanding of use. 'Use' is a slippery word - we ‘use’ it to mean different things and, in design, it can often morph into function - a thing is 'used' through the manipulation of its functionality. This is where engineers and designers can get sidetracked - use is defined in terms of function, cutting out the primary reason for the design - What is someone going to USE it for?

I would suggest that Amplio is trying to create a product (or system or component or whatever it is called) that enables people to enjoy their audio collections to the greatest possible degree. The key word here is enjoy - to give people all the sound that is possible - nothing less, nothing more.

When I am listening to music I don't want to be aware of the process that is bringing it to me, either through artifacts in the sound or by being aware of the equipment that is making my listening possible and I would guess that most other listeners would have similar needs.

Stating this another way, a good system will give me perfect fidelity while being completely invisible.

I can’t have this – perfect and invisible are out of human reach – but how do we get close?

That’s the challenge – I hope to look back in a few years and say we are very, very close.


Thursday, September 21, 2006

So, When Will It Ship?

I've been asked several times about the ship date for our product. I don't have an answer for that, but I can tell you about the changes or improvements we need to make to the current prototype before we are ready to ship a commercial product. In this post, I'll give a general overview of improvements needed for each of these subsystems:
  1. the chassis
  2. power supplies
  3. amplifier modules
  4. soundcard section
    a. computer interface
    b. drivers/software
    c. digital/analog section - DACs, ADC, etc.
I will provide more detailed information about each of these sections in future posts.

As you can see from the prototype photos, the current chassis is not something many people would want in their living or family rooms, unless they're really into the industrial design style. They actually might look kind of cool in an a loft space or something, but that is sooo 90's :). So we need to come up with a more aesthetically pleasing design. We would also like to minimize the size and weight, and allow for optimal heat dissipation. Fortunately, the internal components are relatively small and don't generate too much heat so we should be able to create a chassis that isn't a monster. We'd also really like to design a chassis that would let do-it-yourself (DIY) people build or upgrade their own systems. Much like you can do with PC today. This means the inside of the chassis would include the framing to mount things like power supplies, the printed circuit boards and amp modules. Ideally, the amp modules would simply slide into slots in the back of the chassis.

The main changes we plan to make with the power supplies for our commercial product will be to replace the linear power supplies with switch mode power supplies (SMPS). The latest SMPS technology designed for audio applications is very promising. Compared to general purpose SMPS, the SMPS designed for audio applications usually have much larger capacitors to provide a larger energy reserve for the faster and deeper current demands. General purpose SMPSs are typically designed for fairly constant loads, so they don't usually have large enough capacitance at the outputs for audio applications and adding capacitance to a general purpose SMPS wouldn't work very well because the feedback circuit doesn't take into account this additional capacitance and the added phase shift and oscillation would make it unstable. The main benefit with using the SMPS instead of the linear supplies is since they operate at a much higher frequency, they can be much smaller and lighter than the equivalently powered linear supplies we were using. Since a SMPS recharges its capacitors about 1000 times faster than the rate of a linear power supply, which needs a fairly large transformer and big capacitors to keep up with the current demand, the SMPS can get by with smaller capacitors.

We are pretty pleased with the amplifier modules in the conceptual prototype. The amp modules we've tested are from Hypex Electronics, a Dutch amplifier manufacturer who has developed a very good reputation for high quality products. There are a few things that can be done to optimize these for our application, which will be done if we decide to use their UcD amps in our commercial products. Since we started this business, we have discovered a few other class-D amplifier modules from other manufacturers worth considering. And there is also the possibility of developing our own class-D amp, but unlikely considering the development costs and time. To accommodate our modular chassis design, we would really like to find an amp module that will fit into a small enclosure. This enclosure would be similar to the case of a hard disk drive. It would protect the circuit components, dissipate heat and would allow for an easy method to insert the amp into the back panel of the chassis. If the sizes were standardized, you could upgrade or replace amp modules when newer, better designs were available by simply unplugging the old amp and replacing with the new. We would also be happy to support more than one amplifier manufacturer. Some of the class-D amp modules have a reputation for being very accurate and transparent to the source. These amps sound great, but if the source material isn't very good, like a poor recording, the flaws are pretty noticeable. Other class-D amp modules might be a little more forgiving of these types of recordings. I guess it all depends on your listening preferences. I think it would be nice to have a choice. Now, if only we can find a few manufacturers to work with us on a design for these standard amp cartridges. Wouldn't it be great to have the options of different amp modules just like you currently have with hard drives or video graphics cards?

The soundcard section is where we have the most work ahead of us. The current unit in our conceptual prototype was designed primarily for pro-audio applications - recording and mixing. There are quite a few components that aren't needed in a music playback or home theater system. For example, we don't need 8 balanced inputs if the audio source is the PC. The analog outputs of the pro-audio soundcards are good and usually sound better than your average A/V receiver, but they may not sound quite as good as the high-end dedicated preamp/processors. Their outputs are designed to be good enough for an audio engineer to monitor a mix, but might not meet the needs of someone that is really into critical listening. Our goal is to design a soundcard that sounds as good as some of the high-end dedicated prepros, but at a much lower cost. We've also got a lot of work to do on the software - both the drivers and the control panel applets for controlling things like volume, channel mixing, etc.

Like I said, we'll cover each of these areas in a little more detail in future posts. Please let me know what topics you would like to learn about first.

Wednesday, September 06, 2006

Prototype Photos

Here are some photos of our conceptual prototype:

←This is the front view. It shows the aluminum chassis (0.125" thick) and the controls for the soundcard section. I know it's kind of ugly, but it serves its purpose. This soundcard includes 2 Neutrik combo connectors (for both 1/4" TSR and XLR microphone inputs), a 48V phantom power switch, level controls and LED meters. There's also a basic momentary pushbutton for the amplifier modules on the far right.



→With the cover off, you can see the internal components. The soundcard is near the front (bottom of the pic), the toroids and power supplies are in the middle, and the amp modules are mounted on the back. The amps for the 3 front channels are rated at 400W into 4Ω loads, while the 2 rear channels use amps rated at 180W into 4Ω loads. Since these amps have different operating voltages, we needed 2 toroids and power supplies.

←This picture shows a rear view of the prototype. The amp modules are attached to 1-1/2"x6"x1/4" bars of aluminum, which serve as additional heat sinks. We are using Cardas patented binding posts for the speaker connections. We've also used a quiet (and slow) 120mm fan to pull heat out of the interior space. After testing, we've discovered that the amps run pretty cool and some of our efforts to dissipate heat might be overkill. A little over-engineering can't hurt.

Click on the pictures to get a larger view.

Tuesday, September 05, 2006

I Want Higher Quality Audio from the Online Music Stores

There's been a lot of news about online music services and gadgets that will compete with Apple's iTunes and iPod. Of course everyone's heard about Microsoft's Zune and complimentary music store (for those people who are truly obsessed with everything Zune, take a look at the ZuneInfo.com website or Microsoft's little teaser site). Does anyone know what will happen to the Urge music service that was suppose to be the end result of a collaboration between Microsoft and MTV? I don't think that will be the service tied to Zune, but maybe I'm wrong. There's also the new player coming from Samsung which will be teaming up with the music service MusicNet. And, now MySpace plans to start selling music from unsigned artists. There's also going to be free downloads from SpiralFrog, an advertisement supported alternative to the pay-per-song iTunes model.

I'm not sure what the benefits of the new music services are... Is it an alternative to Apple's proprietary formats and DRM? I haven't read anything about higher fidelity or the addition of album liner notes and high quality album art.

Here's what I'd like: at least CD quality - or losslessly compressed CD quality, with high quality CD cover art (500x500 pixel jpegs or better) along with the information normally included with the album's insert at a reasonable price. I think $.99/track is too high for lossy compressed audio, like iTune's 128 Mbps AAC files. Especially when you compare it to the price of CDs purchased from brick & mortar stores. Besides, I still like to buy the whole album and don't understand why some people purchase only single tracks. If the artist can't put together a full CD worth of good tracks, then I don't buy the CD.

But, there is some good news, or reason to be optimistic about where digital music services are headed. There are a couple of music services listed over in our 'Links' section worth checking out. Both offer high bitrate audio tracks. The first one on the list, Magnatune, isn't really a "music service" like iTunes. They are a new type of record label that sells albums or tracks directly to consumers. You can download albums or tracks from Magnatunes in WAV or lossless FLAC formats. Unfortunately, you are limited to just Magnatune's artists - all of which are very good. So obviously you can't purchase music from popular artists that are already signed with the major labels. The other one, MusicGiants is a competing music service that offers lossless WMA files instead of highly compressed AACs or MP3s. MusicGiants also offers music from all the major record labels. I've also heard MusicGiants will offer high resolution multichannel surround recordings later this month. Since I can't play either SACDs or DVD-Audio with my system, maybe the multichannel surround tracks from MusicGiants will be a great alternative, especially if they are 24bit/96KHz or better. Hopefully they will also include album art and liner notes.

I'd like to hear what other people would like to see/hear from online music services. What formats and bitrates are you willing to accept? Do you want album art and liner notes? What price are you willing to pay? Or, are you satisified with purchasing and ripping CDs (which is what I do mostly)? Please let me know if you hear any news about high quality/higher bitrate audio from other services.

Monday, September 04, 2006

Another Class D product...? Maybe an Apple amplifier...? Oh No!!!

A thread over on diyAudio forums discusses another Class D chip manufactured by Freescale Semiconductor. The first posting includes this link to their white paper (I've also added it to our 'Articles' section).

One of the posters speculates that Freescale will be partnering with Apple to produce a multichannel preamp/amp combo. Seems unlikely to me, but... you never know. There are so many Apple rumours flying around that it has all become just a bit of noise.

Friday, September 01, 2006

Do we really need another disc format for HD?

HD-DVD and Blu-Ray have a new rival -- New Medium Enterprises's High Definition Versatile Multilayer Disc. HD VMD makes use of a red laser and multiple layers to maximize storage capacity.

Check out this article:
Third format to enter high-definition DVD war.

And, here's the website for New Medium Enterprises, the company who's developing VMD.

I think the current battle between HD-DVD and Blu-Ray has created enough of a mess. Do we really need another format to add to the confusion??

Tuesday, August 29, 2006

Connecting to the HTPC

Today most computers communicate with external soundcards using a USB or FireWire connection. Other technologies that might become popular in the future include Audio over Ethernet (AoE) and some new varieties of FireWire like VersaPHY, S800BaseT and POF with IEEE 1394. Our conceptual prototype uses a FireWire connection, which works very well. However, we are looking very closely at other technologies to make sure we provide the best solution for our users.

I also know that some pro-audio external soundcards like M-Audio's Delta 66 and Delta 1010 or Echo Audio's Layla and Gina use a proprietary connection to a dedicated PCI adapter card. Both of these manufacturers are now using either USB or FireWire on all of their newer external soundcard products. We will not be using a proprietary PCI adapter card solution.

USB is the most common method used to connect peripherals to a computer. USB 1.1 was originally meant as a replacement for legacy ports, and a user-friendly, low-cost way to connect peripherals such as keyboards, mice, and printers to a PC. USB was never designed to handle intense multimedia data loads. USB 1.1 is limited to a data rate of only 12Mbits/sec, which is enough bandwidth for CD audio (1.4Mbits/sec). However, it might be difficult for USB 1.1 with it's associated overhead to handle multiple streams of CD audio or DVD-Audio (with 6 channels of 24 bit audio at a sample rate of 96KHz) which requires up to 8.6Mbits/sec. USB 2.0, which is backwards compatible with USB 1.1, provides the fastest data rate currently available at 480Mbits/sec. However, USB uses a host/client (or master/slave) architecture. The PC takes on the role as the host, which requires some overhead to handle all of the arbitration functions and dictate commands to the clients, thus reducing the overall data rates. Data rates are reduced more if addition communication between other clients is required. The maximum length of a USB cable is 5 meters, greater lengths require USB hubs.

Many of the manufacturers of pro-audio soundcards offer an external solution using FireWire (IEEE 1394). FireWire is based on a peer-to-peer technology where each "intelligent" peripheral communicates with each other to provide sustained data rates. Unlike USB, no additional PC overhead (system memory or CPU) is needed to sustain the data rates. FireWire includes support for memory-mapped devices, which allows high-level protocols to run without forcing numerous interrupts and buffer copy operations on host CPUs. The most common FireWire in use today, IEEE-1394a, provides data rates up to 400Mbits/sec with cable lengths limited to 4.5 meters, but up to 16 cables can be daisy chained using an active repeater, external hub or internal hubs included in many FireWire devices. The maximum length possible with any configuration of IEEE-1394a is 72 meters. A newer FireWire standard, IEEE-1394b (sometimes called FireWire-800) provides a data rate of 800Mbits/sec (but promises to support speeds of 1600Mbits/sec. to 3200Mbits/sec. in the future) and cable lengths of 100 meters when using optical fiber or CAT5 cabling. However, if you read the fine print, these longer lengths only support data rates of 100Mbits/sec when using CAT5 cabling. A future version of FireWire, p1394c is suppose to provide data rates of 800Mbits/sec for cable lengths of 100 meters.

Theoretically USB 2.0 should be faster than FireWire IEEE 1394a. Each FireWire device has to negotiate for bus access and the FireWire bus must wait until a given signal has been sent to all devices on the bus. The more devices on the bus the lower the performance. While USB is only limited by the host-client branch, not the whole network. USB's host-client technology also allows the host to allocate more bandwidth to higher priority devices. Even though the USB 2.0 spec of 480Mbits/sec is higher than FireWire's (IEEE 1394a) 400Mbits/sec, the increased CPU and host overhead due to the host/client technology of USB 2.0 reduces its sustained throughput to rates lower than those of IEEE 1394a. USB comes standard on over 90% of computers shipped today (probably more than 90%, now). Unfortunately, FireWire does not come standard with most new PCs. However, I've noticed that it is included on many of the motherboards that are popular with people who build their own HTPCs. Anyhow, both FireWire and USB 2.0 can handle the audio throughput needs of an external soundcard.

Looking into the future, it appears that the performance of USB isn't really going to change much. The only references to a future version of USB talk about wireless USB (WUSB). Wireless USB sounds interesting. You'll get USB 2.0 performance within a range of 3 meters. Between 3 and 10 meters, WUSB can operate at 110Mbit/sec. The future versions of FireWire are even more interesting. I'm not sure exactly what the bandwidth requirements will be for future audio formats like HD-DVD and Blu-Ray (probably, not much more than DVD-Audio's 8.6Mbit/sec, but you never know). And who knows, maybe there will be something better after these two formats kill each other off. Anyhow, the speed improvements of future versions of FireWire might be very useful. What's even more exciting is the fact that the cable lengths will let us support features like whole-house multi-zone audio much easier. With S800BaseT maybe we will be able to have an HTPC in the family room with our soundcard/amp, and others in the kitchen or dining area and bedrooms. All of the PCs are connected via FireWire to either multichannel soundcard/amps or stereo soundcard/amps. They are also connected to each other over the S800BaseT network. Because of the network connection, any of the PCs will be able to recognise all of the other soundcard/amps on the network. That is, your PC will actually have every soundcard on the network in its list of audio devices. With the appropriate software, like J.Rivers Media Center, they'll be able to set up multiple zones. From any one of the PCs you'll be able to pipe music all over the house. For parties, the same tune can play in every zone. However, you will still be able to control each soundcard from the local PC. Hopefully the software will be able to manage when the soundcard is under local control or is available across the network. Anyhow, the possibilities are very exciting since you should be able to connect all FireWire devices up to distances of 100 meters and still maintain S800 (800Mbits/sec) speeds.

After reading several articles or papers describing Audio over Ethernet, I'm not sure if it will ever come into the mainstream. First, there are a lot of proprietary solutions and without a standard, it's unlikely to move beyond its niche. The technology is really geared to professional applications like auditoriums or large recording studios. Second, if S800BaseT takes off, it looks like there will be no need for audio over Ethernet. Anyhow, it is another technology that we will keep an eye on.

I'm sure some people reading this post are wondering why I haven't included HDMI in this discussion. It's because I don't think HDMI (High Definition Multimedia Interface) will ever replace USB or FireWire as a way to connect to external soundcards. Instead, it will probably replace S/PDIF because it is also basically just a one way connection. It is a much higher bandwidth digital connection. Instead of the S/PDIF limits of 2 channel PCM or multichannel Dolby Digital or DTS compressed audio, HDMI can handle 8 channels of uncompressed audio (in addition to all of the HD video). We are considering using an HDMI input instead of/or in addition to S/PDIF as our digital input option. We are already beginning to see HDMI connectors on graphics cards, high resolution displays and A/V receivers. In the next few months HDMI connectors will be included on new motherboards. Another big part of HDMI is content protection and HDCP, but I don't really want to cover that in this blog entry. Maybe some other time.

Tuesday, August 22, 2006

PSA: "Don't Download This Song"

Every so often I'm moved by something that I think would make a good public service announcement. Here's an important message (in the form of a song) warning of the dangers of illegally downloading music from filesharing sites.

Monday, August 21, 2006

Vista Audio - Digital Room Correction, Bass Management, etc.

In a recent AVSforum post titled, "Audio Processing in Vista Explained", Amir Majidimehr, Corporate Vice President of Microsoft’s Consumer Media Technology Group, writes about the new audio capabilities planned for Vista. New audio features included in Vista are digital room correction (DRC), bass management, loudness equalization, headphone virtualization, and channel control tools.

When asked, if after you plug your PC into an A/V receiver and perform the room correction calibration on the PC and then disconnect the receiver from the PC, 'will the receiver retain the calibration settings?', Amir replied, "Unfortunatly not. All the processing is done inside the PC and only works if you use the PC as the source, driving your receiver. Take away the PC and there is nothing there anymore. For your receiver to have similar capabilities, it would have to have a ton more hardware in it." Anil then favorably compared Vista's room correction capabilities to a high end TacT processor by saying, "The TacT processors do what you say but the one I have cost me a cool $10K and it does less in some respects than Vista!"

For a quick explanation of what DRC is and how it can benefit you and your system, check out this DRC guide.

The bass management feature is very flexible and doesn't have some of the limitations you find with the bass management on most A/V receivers. For example, with Vista's bass management, you can have any combination of large or small speakers, with or without a subwoofer. The crossover point can be set to whatever your loudspeakers need. When sending a full range signal to any of your small speakers, the portion of the signal below the crossover point will be routed to the subwoofer, or in the case of a system without a subwoofer, the lower frequencies can be routed to the large speakers.

Most A/V receivers won't let you send a full range signal to the front speakers if the subwoofer is engaged. They force you to filter out the low frequencies from the fronts and send everything below the fixed crossover point to the subwoofer. This works okay with a sub/sat system, but isn't very appealing for anyone who has large or full-range loudspeakers in the front. There are also some A/V receivers and processors that will not send a signal to the subwoofer when it is set to stereo mode. Also, with most of the A/V receivers and processors, the subwoofer output jack is low-pass filtered so any signal above the frequency setting (usually in the 100Hz-150Hz range) is blocked. Most powered subwoofers also have a built-in low pass filter, and when the two filters combine you are increasing the steepness of the filter. Too steep of a filter slope makes for worse sound. Anyhow, it sounds like Vista's bass management feature will let you avoid these types of limitations.

Vista now has a new audio mixer that according to Amir works much better than Windows XP's Kmixer. Kmixer resampled all audio to 48KHz, unless the sample rate was already 48KHz. Audio originally from a CD source, which uses a sample rate of 44.1KHz, was always resampled to 48KHz and the method used by Kmixer degraded the sound quality. With the new mixer, maybe the algorithms for resampling are much better so the sound quality remains high. The new mixer also has a user mode audio engine where a user can set the default sample rate and includes an exclusive mode which provides access directly to the soundcard. With the user mode, the mixer will not apply resampling at all. However, its not clear if the mixer will just leave the source material alone so that if you are playing ripped CDs it will use 44.1KHz and when playing from a DVD, it will automatically switch to the native 48KHz.

Be sure to read Amir's posts in the thread linked above to learn about all of the other great audio processing features. Also, take a look at this post in the Windows Vista Team Blog about the new audio features in more detail. And here's an interview with Microsoft PM Hakon Strande who also talks about high definition audio in Windows Vista.

These features will only work if you send either a 2-channel PCM stream over S/PDIF to your A/V receiver, or analog signals directly to your receiver/amps. So for anything more than 2-channel stereo, including 2.1 (stereo plus subwoofer), you will need to use analog outputs. This might be a problem because most people prefer using their A/V receiver's processor and DACs especially when they perform better than the DACs included with inexpensive soundcards or the built-in audio chips on the motherboard. They also feel anytime an audio signal is present inside a computer, the signal will pick up noise generated by other internal components like the computer's power supply or hard drives, thus decreasing the sound quality even further.

However, using one of our future products, you'll be able to take full advantage of Vista's advanced audio capabilities and enjoy excellent sound quality because we use the same components found in high end dedicated DACs and the best pro soundcards. Since these DACs are located in our box, you don't have to worry about any possible noise generated inside the computer. In addition, our amp modules are very efficient, have lots of power, generate less heat and sound better than most amps inside your typical A/V receiver.

Friday, August 18, 2006

Promoting this blog

I've been trying to read about all the things we can do to promote this blog. After all, if no one knows about this, they can't read about what we are doing. The more people who read this, the greater the chance we'll get some very useful feedback helping us to build great products.

So, I apologize for posting something that isn't directly related to our technology or development. I'll try to keep these posts to a minimum and will probably delete them if I think they no longer serve their purpose.

BTW, if anyone knows of other useful techniques to help generate more (some) traffic, please let us know. Hmmm... maybe we should change the name of the site to "AmplioPod" and see if we get a cease-and-desist letter from Apple. Maybe that will draw some attention. Probably not the kind we want.

One of the recommendations in Blogger's help tells us to sumbit (I think they really mean "submit", but sumbits might be cool) your address to blog search sites and directories. There are a few sites they recommend like Technorati (Technorati Profile), Daypop, Blogdex and Popdex. Eventually we'll try them all. For the submissions to work, I have to insert these links into my post. Done. Now we'll see if that works.