Re: DSP for audio work

Article View: sci.electronics.design

Article #2408

Back to sci.electronics.design Previous Next

#2408

From: Adam Seychell
Date: Thu, 28 Mar 2002 02:10

24 lines
2207 bytes

"James" <jamesf@xxxnec.com.au> wrote in message news:<1017176265.755781@busy.neca.nec.com.au>...
> Hi,
> 
> I have (attempted) implemented DSP filtering using a PC and two sound cards
> under DOS - no real operating system overheads. Big problem with using
> multiple sound cards is that they all have individual clocks, and may drift
> relative to one another. My sound cards, both sound blaster but about 4
> years between them, have a clock error of about 1%, quite significant if
> your output overtakes your input.
> 
> If you do proceed this way, creative had quite a bit of info on programming
> their sound cards.
> 
> James.
> 


Worse still is that some sound cards have different clocks for
recording and playback. If a signal generator is connected to one of
the sound card inputs and a program is running that reads the ADC to a
cycling buffer then plays it back, at  a fixed delay, then the phase
difference between the DAC output and the signal source wonders all
over the place. This is easily seen on a dual channel CRO. That really
throws a spanner in the works

Technical Details

Message-ID: <21a524b0.0203271810.551852f9@posting.google.com>

Path: arc1-ca.pugleaf.net!archiver1.google.com!postnews1.google.com!not-for-mail

References:

<3c9da171.2670537@news.optusnet.com.au> <2drr9ucraffrrnf2ad0bp48u4nmk6tdal3@4ax.com> <3c9f0323.29265355@news.optusnet.com.au> <21a524b0.0203252126.7e2b7297@posting.google.com> <1017176265.755781@busy.neca.nec.com.au>

Show Full Headers

Complete Article Headers

X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 112d1e,d43e8f202cc9402f
X-Google-Attributes: gid112d1e,public
X-Google-Thread: 103407,d43e8f202cc9402f
X-Google-Attributes: gid103407,public
X-Google-ArrivalTime: 2002-03-27 18:10:06 PST
Path: arc1-ca.pugleaf.net!archiver1.google.com!postnews1.google.com!not-for-mail
From: aseychell@vet.com.au (Adam Seychell)
Newsgroups: sci.electronics.design,aus.electronics
Subject: Re: DSP for audio work
Date: 27 Mar 2002 18:10:05 -0800
Organization: http://groups.google.com/
Lines: 24
Message-ID: <21a524b0.0203271810.551852f9@posting.google.com>
References: <3c9da171.2670537@news.optusnet.com.au> <2drr9ucraffrrnf2ad0bp48u4nmk6tdal3@4ax.com> <3c9f0323.29265355@news.optusnet.com.au> <21a524b0.0203252126.7e2b7297@posting.google.com> <1017176265.755781@busy.neca.nec.com.au>
NNTP-Posting-Host: 203.39.245.7
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
X-Trace: posting.google.com 1017281406 16292 127.0.0.1 (28 Mar 2002 02:10:06 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: 28 Mar 2002 02:10:06 GMT

Reply to Parent Message