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.