Date: Tue, 26 Aug 1997 13:58:52 -0700 From: Amancio Hasty <hasty@rah.star-gate.com> To: Luigi Rizzo <luigi@labinfo.iet.unipi.it> Cc: tinguely@plains.NoDak.edu, freebsd-multimedia@FreeBSD.ORG, sales@omt.com Subject: Re: Regard to phone call about FreeBSD drivers Message-ID: <199708262058.NAA01230@rah.star-gate.com> In-Reply-To: Your message of "Tue, 26 Aug 1997 21:37:55 %2B0200." <199708261937.VAA00302@labinfo.iet.unipi.it>
next in thread | previous in thread | raw e-mail | index | archive | help
If the opti931 based soundcards derive their clock timing info then you have a bigger problem because typically the isa timing info is not very accurate. Don't worry about your english . My english is far worse than yours 8) I am Puerto Rican Cheers, Amancio >From The Desk Of Luigi Rizzo : > > >From The Desk Of Luigi Rizzo : > > > make it $20-$40 for a soundcard. The OPTI931 has a street price of $20 > > > here in italy, and CS4236 (assuming you can find them) are little more > > > expensive. For conferencing purposes they are both more than ok > > > (Crystal much better since it is better documented and less buggy...) > > > > Well, it depends the clock they use and the quality of the analog > > parts. Conferencing is one thing however I think that you may > > want to use the soundcard for other things like playing back > > audio mpeg files. By far most PC soundcards fall short on > > the clock part . Interestingly, the old sparcs used to have a > > a cs4231 and the accuracy of their dsp subsystem has always > > been better than your typical PC soundcard -- the primary difference > > from an accuracy stand point of view is just the clock part. > > the opti931 boards I have take the clock from the 14.3xxx clock on the > ISA bus, but the internal division do not yeield the exact frequencies > (44.1KHz, 8KHz, etc.) one would want, there is some 0.15% or so of > difference. I doubt one would notice this (well unless it uses several > machines with different clocks at the same time to simulate an > orchestra, each machine playing a different set of instruments...). > > Also, if there are no short term drifts I believe the > differences can be compensated (e.g. in software by adding/dropping > samples every now and then). > > Apart from clock stability, I suppose that dma overruns/underruns might > also make the clock appear to have a different frequency (sorry for the > convoluted sentence, I am italian...). > > Cheers > Luigi
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199708262058.NAA01230>