From alsa-devel-owner@alsa.jcu.cz  Sat Nov 28 11:37:49 1998
Received: from entry.jcu.cz (IDENT:perex@entry.jcu.cz [160.217.1.111])
	by marvin.jcu.cz (8.9.1a/8.9.1) with SMTP id LAA01549;
	Sat, 28 Nov 1998 11:36:02 +0100
Date: Sat, 28 Nov 1998 11:36:02 +0100 (CET)
From: Jaroslav Kysela <perex@jcu.cz>
To: Paul Barton-Davis <pbd@op.net>
cc: alsa-devel@jcu.cz
Subject: Re: Linux sound cards latency 
In-Reply-To: <199811280249.VAA13191@renoir.op.net>
Message-ID: <Pine.LNX.3.96.981128112823.960E-100000@entry.jcu.cz>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Reply-To: alsa-devel@alsa.jcu.cz
Sender: alsa-devel-owner@alsa.jcu.cz
Precedence: list

On Fri, 27 Nov 1998, Paul Barton-Davis wrote:

> I just want to note that MIDI folk complain about the 2ms latency
> typically introduced by software MIDI-thru connections, and claim that
> its very audible.

Does anyone measure exactly this latency? I mean on MIDI input and MIDI
output pins... This maybe also software and hardware dependent..

Here are some words from Frank's pages: Because midi runs at 31.250 kbps,
it will take 0.96 ms to receive a note on message (without running state).
Sending this event will also take 0.96 ms, so the event arrives 1.92 ms
later at the playback device, which is faster than the typical delay
within synthesizers before a sound is produced.

If 2ms latency is audiable, user should probably buy some hardware which
supports data processing via DSP for PCM data manipulation...

						Jaroslav		

-----
Jaroslav Kysela <perex@jcu.cz>
Academic Computer Centre, University of South Bohemia
Branisovska 31, C. Budejovice, CZ-370 05 Czech Republic


