I ran into a benchmark tool at http://github.com/koppi/alsa-midi-latency-test/
and ran it though my MidiSport 2x2 Anniversary Edition (no firmware upload
required :) ) and Edirol UA-25EX.
Attached are the results on an untuned Debian Testing machine (2.6.30-1-686)
started with 'chrt -f 50 ./src/alsa-midi-latency-test -s 40'
The Edirol sure outperformed the MidiSport - the difference didn't seem huge
though.
(at the time of writing you need to add some symlinks to
/usr/share/automake-1.10/... to make it build right, mailed the author about
that already).
Regards,
Arnout
On Thu, Sep 24, 2009 at 07:56:22AM -0400, Dave Phillips wrote:
> I've been experimenting with MIDI control from one machine to another. I
> checked the timing of a single note played simultanesouly by instances
> of QSynth on both machines and was surprised to hear a very noticeable
> flamming. I then replaced the MidiSport 2x2 with my Edirol UA25 and the
> flamming disappeared. Both are USB interfaces, btw. MIDI routing between
> the machines is handled by a Yamaha MJC8 and has never been problematic
> with that box.
>
> So, my question(s): Is the MidiSport just poorly designed and is there a
> further condition or module option that can correct the timing delay
> from that unit ?
>
> Best,
>
> dp
>
> _______________________________________________
> Linux-audio-dev mailing list
> Linux-audio-dev@lists.linuxaudio.org
> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
rnou...@bird:~/progs/alsa-midi-latency-test$ chrt -f 50
./src/alsa-midi-latency-test -s 40 --input 28:0 --output 28:0
> calibrating high precision timer loop.. done.
time diff = 0.00
loops/sec = 8661432571218325.00
> sampling 10000 midi latency values - please wait..
> press Ctrl+C to abort test.
> skipping first 40 latency samples.
sample; latency_ms; latency_ms_worst
41; 2.30; 2.30
42; 2.78; 2.78
43; 2.81; 2.81
165; 2.85; 2.85
166; 2.86; 2.86
167; 2.91; 2.91
567; 2.93; 2.93
666; 2.93; 2.93
667; 2.97; 2.97
1110; 3.17; 3.17
2581; 3.41; 3.41
2582; 3.59; 3.59
10000; 2.26; 3.59
> done.
> latency distribution:
...
1.1 - 1.2 ms: 7 #
...
1.5 - 1.6 ms: 2 #
1.6 - 1.7 ms: 8 #
1.7 - 1.8 ms: 37 #
1.8 - 1.9 ms: 12 #
1.9 - 2.0 ms: 6 #
2.0 - 2.1 ms: 11 #
2.1 - 2.2 ms: 10 #
2.2 - 2.3 ms: 7131 ###################################################
2.3 - 2.4 ms: 2114 ###############
2.4 - 2.5 ms: 74 #
2.5 - 2.6 ms: 345 ###
2.6 - 2.7 ms: 172 ##
2.7 - 2.8 ms: 26 #
2.8 - 2.9 ms: 16 #
2.9 - 3.0 ms: 21 #
...
3.1 - 3.2 ms: 1 #
3.2 - 3.3 ms: 2 #
...
3.4 - 3.5 ms: 2 #
3.5 - 3.6 ms: 1 #
arnou...@bird:~/progs/alsa-midi-latency-test$ chrt -f 50
./src/alsa-midi-latency-test -s 40 --input 24:0 --output 24:0
> calibrating high precision timer loop.. done.
time diff = 0.00
loops/sec = 8661432571218325.00
> sampling 10000 midi latency values - please wait..
> press Ctrl+C to abort test.
> skipping first 40 latency samples.
sample; latency_ms; latency_ms_worst
41; 2.82; 2.82
42; 3.37; 3.37
72; 3.51; 3.51
316; 3.63; 3.63
1520; 3.69; 3.69
3927; 3.72; 3.72
4133; 4.55; 4.55
10000; 2.93; 4.55
> done.
> latency distribution:
...
1.8 - 1.9 ms: 1 #
...
2.2 - 2.3 ms: 73 #
2.3 - 2.4 ms: 63 #
2.4 - 2.5 ms: 15 #
2.5 - 2.6 ms: 9 #
2.6 - 2.7 ms: 13 #
2.7 - 2.8 ms: 4 #
2.8 - 2.9 ms: 8496 ###################################################
2.9 - 3.0 ms: 687 #####
3.0 - 3.1 ms: 172 ##
3.1 - 3.2 ms: 262 ##
3.2 - 3.3 ms: 158 #
3.3 - 3.4 ms: 7 #
3.4 - 3.5 ms: 9 #
3.5 - 3.6 ms: 11 #
3.6 - 3.7 ms: 12 #
3.7 - 3.8 ms: 4 #
...
4.1 - 4.2 ms: 1 #
...
4.5 - 4.6 ms: 1 #
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