Re: Audio interfaces survey

["Regis Rossi A. Faria" <regis@xxxxxxxxxx>]

Hi,

sound cards generally target PC/Mac buses, like PCI or USB or Firewire: 
this is an issue: connectivity! Firewire is apparently more stable than 
USB for audio applications specially regarding high bitrates transfer 
sustain, and PCI bus is the one which offers lower latencies. Terratec, 
Yamaha, Creative and many others target this market.

digital audio interfaces target not only computer buses, but also studio 
gear which connectivity to analog mixers and analog/digital/analog 
converters: RME, MOTU, Egosys, M-Audio, and many others target this 
market. Usually they offer lots os possible digital formats/protocols 
for I/O: ADAT, TDIF (both now decrasing popularity), Firewire and USB 
(increasing popularity), PCI, SPDIF, AES/EBU, very few would support 
MADI (AES10) and some are very focused in having multiple (usually 8) 
analog I/O.

D/A and A/D conversion are now stable in the range 96 kHz/20bit, most 
cards accept simultaneous I/O of multiple channels in this format,  and 
lots of cards/interfaces offer now 192 kHz/24bits, although not 
supporting many inputs or outputs operating at the same time in realtime.

You should pay attention to the pictures of the back and front panels, 
where you will really realize how many inputs and outputs the interface 
has, and then how many inputs and outputs you can connect phisically: 
many manufacturers count on maximum possible digital channels supported 
by the card, but these figures generally are not accessible in the real 
conectors, or require that you have several different gear at the same 
thime, for example an ADAT system, a SPDIF I/O, RCA line inputs and the 
TRS/XLR I/Os. That's tricky.

Other issues regards to OS compatibility and support, THD and SNR 
figures, dependency of a PC/Mac to operate or standalone, mobile or rack 
mount, and support to additional formats (ex: MIDI).

Hope this helps,
regards,

Regis Rossi Faria
LSI-University of Sao Paulo
regis@xxxxxxxxxx

Olivier Tache escreveu:

> Dear list,
>
> I'm currently working on a very general survey of digital audio 
> interfaces, but i'm unfortunately lacking practical experience on the 
> subject. It would be very kind if those who are willing to could 
> briefly tell me about the typical issues they encounter when dealing 
> with sound cards (latency, D/A and A/D conversion, etc.) or provide 
> pointers to ressources that could help me in my *quest* (apart from 
> those wich have already been given here a few months ago).
>
> Thanks a lot.
>
> Regards,
> Olivier