Subject: Re: [linux-audio-dev] [OT] Digital mixing console and soundcards
From: Remco Poelstra (rjpoelstra_AT_home.nl)
Date: Mon Mar 11 2002 - 23:05:38 EET
On 2002.03.10 00:09 David Olofson wrote:
<snap>
> I totally agree.
>
Ok, it's certainly true that it makes development very easy and in case I
can use normal ALSA drivers, I might as well use ecasound or ardour for
the mixing and than I only have to build the knobs. (and have hd recording
for free :) )
> If you have extreme latency requirements enough that Linux/lowlatency
> doesn't cut it (that is, you need < 3 ms input -> output digital
> latency), I have news for you;
>
Well, I need latency below 3ms,preferrably that's inclusive A/D D/A. (ok,
it might not be possible, but I try to get as close as possible to it)
<I don't like bad news, so I snap it away>
> Good news:
> Good news 2:
>
Ok, I'll use a multichannel card of course, might be more than one in the
future.
If I can afford 24 bit/96 kHz I'll buy it.
But how do I know what cards uses a single dma stream for all channels?
>
> As to latencies and not using an OS - indeed, there's no reason not
> to use an OS. Taking it to the extrem, RTLinux and RTAI commonly
> deliver worst case latencies below 10 µs on P-III and Celeron
> systems, and even better on PPC systems. (PPC has much better IRQ
> handling than x86 - mostly because it's not dragging around that
> badly designed legacy garbage that is the "PC chipset".)
>
> If you need to cut latency below that point, please tell me where you
> found your AD/DA chips! ;-)
>
If RTLinux is even faster than the converters, I'll stick to linux and use
ALSA. One problem what of the many LL patches should I use?
> So get a real OS, and hack away - no hairy cross-compiling setups
> need! :-)
Of course if I'm going to use linux, I'll start development with my
current PC and soundcard (SB Live). I suppose ecasound and ardour and such
already try to get latencies down to the limit, so at the time I'm going
to buy a multi channel card, I don't have to change the software to get
the most out of the card?
Thanks in advance,
Remco Poelstra
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