A Beginner's Guide to Computer Audio

[Lee]

Friends,

I recently gave a very basic (too much so for some of you I imagine) talk on computer audio to the AV Club of Atlanta. Here is a link to the slides:

http://www.mediafire.com/?3ecwdh8gaptjl1t

I hope this may be useful to some of you. For more advanced users the dCS Guide written by Chris Connaker is the best I have found so far.

Lee

P.S.

There is one change I need to make. You can do 24/192 over USB2.

[ted_b]

Lee, with proprietray USB drivers on USB2.0 you can do 32/384 (M2tech Young DAC inhouse) and up to 5.6Mhz (Playback Designs forthcoming MPS-3).

[Lee]

Lee, with proprietray USB drivers on USB2.0 you can do 32/384 (M2tech Young DAC inhouse) and up to 5.6Mhz (Playback Designs forthcoming MPS-3).

Thanks Ted. At that level you are at DSD quality in my opinion.

[ted_b]

Lee, well at least DXD (24/352). Some say DXD is equivalently as resolving as DSD128 (with 24/176 being equivalent to DSD64) but I'm not sure really. It sounds great, but the selections aren't exactly my cup oif tea all the time.

[Lee]

I have not had experience with DXD buit based on my recording I still think DSD is more natural than 24/176 although that is the rate I record at.

[Vincent Kars]

I do think dCs guide is not very clearly written concerning USB.

You can set USB to isochronous transfer.
This is a kind of 'soft' realtime mode used for AV streaming.
 Guaranteed access to USB bandwidth.
 Bounded latency.
 Stream Pipe - Unidirectional
 Error detection via CRC, but no retry or guarantee of delivery.
 Full & high speed modes only.
 No data toggling.
http://www.beyondlogic.org/usbnutshell/usb4.shtml

In this transfer mode you can have 3 types of endpoints
Synchronous
The clock is directly derived from the 1 kHz frame rate.
Adaptive
in this mode the clock comes from a separate clock generator (usually implemented as a PLL referenced by a crystal oscillator) that can have its frequency adjusted in small increments over a wide range. A control circuit (either hardware or firmware running on an embedded processor) measures the average rate of the DATA coming over the bus and adjusts the clock to match that. Since the clock is not directly derived from a bus signal it is far less sensitive to bus jitter than synchronous mode.
Asynchronous
In this mode an external clock is used to clock the data out of the buffer and a feedback stream is setup to tell the host how fast to send the data. A control circuit monitors the status of the buffer and tells the host to speed up if the buffer is getting too empty or slow down if its getting too full.
http://www.thewelltemperedcomputer.com/KB/USB.html

In your guide I should focus on adaptive and async only.
The guaranteed bandwidth is for the USB only. It is not guaranteed that the processor will feed the USB hub in time (drop outs)

Slide7: dbPoweramp for ripping? Faster and easier to configure then EAC
Slide 14: WASAPI? (automatic sample rate switching in Win)
Slide 17: You mean lossless Compression?
Slide 18: You say USB 2 & 3 but this are the general USB specs.
USB audio class 1= 24/96 (runs on USB1= 12 Mb/s)
USB audio class 2=24/192 (runs on USB2 in high-speed mode= 480 Mb/s)

Maybe a bit about Tagging?

Good guide.

[Lee]

Good points Vincent. I appreciate the feedback.

[Morbius]

For more advanced users the dCS Guide written by Chris Connaker is the best I have found so far.

Lee,

Thanks. The dCS Guide is very well written. I can see where people who are not familiar with
computer communication protocols might have a hard time with this guide. Therefore, the
admonishment, "for more advanced users" is appropriate.

Greg

[microstrip]

This is really a beginner question: how can I convert a track from a CD in a .wav file? I have the free version of MediaMonkey.

[amirm]

This is really a beginner question: how can I convert a track from a CD in a .wav file? I have the free version of MediaMonkey.

Use Windows Media Player. Go into Tools->Options->Rip Music and under Format, select "WAV(lossless)."