gigo@newsound:~$ lsusb
Bus 001 Device 001: ID 1d6b:0002
Bus 003 Device 001: ID 1d6b:0001
Bus 002 Device 001: ID 1d6b:0002
Bus 005 Device 001: ID 1d6b:0001
Bus 004 Device 004: ID 0763:1033 Midiman
Bus 004 Device 001: ID 1d6b:0001
I tried the archives of linux-audio-tuning, as recommended by the
author of alsa-midi-latency-test, but turned up nothing useful.
Just for jolly, I tested the HDSP MIDI interface, and got a max delay
of 1.12mS. Nice, but one MIDI cable isn't enough.
So, I'm looking for ideas for ideas to improve the USB interface
situation.
Also, any rumours of USB extenders with short (microsecond) delay
would be interesting. The cheap one I used seemed to produce jittery
delays up to 250mS sometimes, and appeared as a USB hub with an NEC
chipset on lsusb.
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12-30-2009, 08:35 PM
Ralf Mardorf
MIDI timing
Hi
your mail is the only mail I'm able to read today, resp. I even have no
time to read your mail, but I'm to curious to delay reading it .
I don't have latency issues, but jitter. 1/4 @ 120 BPM = 500 ms, 1000
ms, 1500 ms, 2000 ms etc. ... Cubase = Windows XP, the others are timers
used as sequencer timer source for Qtractor on 64 Studio 3.0-beta3:
I'm missing one information. Does your graphics use the main memory for
frame buffer or has the graphics it's own memory?
I'm using an on-board graphics, thus it needs to access the main memory,
because it doesn't have it's own memory.
Purely hypothetical: Using the same RAM for Linux and the graphics might
cause unwanted interrupts and timing issues. After a short search in the
www I guess you are using a graphics with it's own memory.
I reckon your BIOS is upgraded?!
The computer I'm using has got a CPU model "AMD Athlon(tm) X2 Dual Core
Processor BE-2350", socket AM2. The MIDI interface is an Swissonic USB,
a very cheap one.
Again, more information next year.
I'm not able to use my external MIDI equipment with the PC. Using the
Atari ST or Commodore 64 there were no problems.
Cheers,
Ralf
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12-30-2009, 08:52 PM
Ralf Mardorf
MIDI timing
geoff wrote:
> Just for jolly, I tested the HDSP MIDI interface, and got a max delay
> of 1.12mS. Nice, but one MIDI cable isn't enough.
It isn't enough if you like to send a lot of data real-time, e.g. SysEx
to control filters. It also isn't enough if some of your old synth only
receive in omni mode, but it's enough for many productions, if you'll
use a MIDI thru box, instead of connecting several receivers by a MIDI
thru chain. I Would be happy, if I would have one interface with such
low "latency" = ? jitter ?. Respectively, does this mean jitter +/- 1.12
= 2.24 ms?
Perhaps you'll be able to use some of your equipment, when connecting a
MIDI thru box.
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01-05-2010, 03:55 PM
geoff
MIDI timing
On Tue, 29 Dec 2009 18:49:16 +0000, geoff <ot0006@0x29a.org.uk> wrote:
>Hi there,
>
>I seem to have a jitter issue with external MIDI timing.
Still stuck at ~30mS jitter.
Booted with "hpet=force", and the kernel (and thus ALSA) found an
HPET, but the timing stayed the same.
At Ralf's suggestion, I ran up Win XP Home SP2, installed the latest
MidiSport drivers, installed MIDI-OX and ran a loopback test.
This relies on the accuracy of the MIDI-OX timestamping, but I seemed
to be getting a consistent 5mS round trip from the USB interface.
Which seems to indicate there's a software level incompatibility with
USB MIDI (or at least, MidiSport USB MIDI) and 3.0b3.
I'm looking for suggestions to ameliorate this situation.
I'd also like to know whether it's worth me putting this on the 3.0b3
bug list.
And can anyone describe their measured low-jitter external MIDI setup
with at least 4 ports, please? (where low is < 10mS)
Studio64 version:
Motherboard:
MIDI interface:
Number of ports:
Best,
Geoff
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01-06-2010, 03:27 AM
Gustin Johnson
MIDI timing
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
geoff wrote:
> On Tue, 29 Dec 2009 18:49:16 +0000, geoff <ot0006@0x29a.org.uk> wrote:
>
>> Hi there,
>>
>> I seem to have a jitter issue with external MIDI timing.
>
> Still stuck at ~30mS jitter.
>
> Booted with "hpet=force", and the kernel (and thus ALSA) found an
> HPET, but the timing stayed the same.
>
> At Ralf's suggestion, I ran up Win XP Home SP2, installed the latest
> MidiSport drivers, installed MIDI-OX and ran a loopback test.
>
> This relies on the accuracy of the MIDI-OX timestamping, but I seemed
> to be getting a consistent 5mS round trip from the USB interface.
>
> Which seems to indicate there's a software level incompatibility with
> USB MIDI (or at least, MidiSport USB MIDI) and 3.0b3.
>
> I'm looking for suggestions to ameliorate this situation.
>
something like
http://www.philrees.co.uk/products/thruunit.htm#v4
or
http://www.philrees.co.uk/products/thruunit.htm#v8
I have never needed or used these sorts of things, but it may be useful
for you.
> I'd also like to know whether it's worth me putting this on the 3.0b3
> bug list.
If you can fill out a useful bug report then go for it.
>
> And can anyone describe their measured low-jitter external MIDI setup
> with at least 4 ports, please? (where low is < 10mS)
>
I have a total of 3 midi devices (a keyboard, BCF2000, and a synth).
I use the 2 ports on my Hammerfall. I also have a midisport 2x2 that I
have not used for years. If I get some time over the next couple of
days I will run that midi test.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
On Tue, 05 Jan 2010 21:27:32 -0700, Gustin Johnson
<gustin@echostar.ca> wrote:
<snip>
>-----BEGIN PGP SIGNED MESSAGE-----
>Hash: SHA1
>
>geoff wrote:
>> On Tue, 29 Dec 2009 18:49:16 +0000, geoff <ot0006@0x29a.org.uk> wrote:
>>
>>> Hi there,
>>>
>>> I seem to have a jitter issue with external MIDI timing.
>>
>> Still stuck at ~30mS jitter.
>>
>> Booted with "hpet=force", and the kernel (and thus ALSA) found an
>> HPET, but the timing stayed the same.
>>
>> At Ralf's suggestion, I ran up Win XP Home SP2, installed the latest
>> MidiSport drivers, installed MIDI-OX and ran a loopback test.
>>
>> This relies on the accuracy of the MIDI-OX timestamping, but I seemed
>> to be getting a consistent 5mS round trip from the USB interface.
>>
>> Which seems to indicate there's a software level incompatibility with
>> USB MIDI (or at least, MidiSport USB MIDI) and 3.0b3.
>>
>> I'm looking for suggestions to ameliorate this situation.
>>
>something like
>http://www.philrees.co.uk/products/thruunit.htm#v4
>or
>http://www.philrees.co.uk/products/thruunit.htm#v8
>
>I have never needed or used these sorts of things, but it may be useful
>for you.
Thanks for the suggestion.
I had a configuration similar to that in the early 90s. To prevent the
"drummer" sounding increasingly drunk as more (high controller
density) parts were added to the piece, I replaced it with a Unitor 8,
an eight port MIDI interface of the period.
It doesn't take much stacking on a single MIDI cable to bring that
inebriation about, imho. Plus, you need a switch box for patch
editing, which is a pita.
<snip>
>>
>> And can anyone describe their measured low-jitter external MIDI setup
>> with at least 4 ports, please? (where low is < 10mS)
>>
>I have a total of 3 midi devices (a keyboard, BCF2000, and a synth).
>I use the 2 ports on my Hammerfall. I also have a midisport 2x2 that I
>have not used for years. If I get some time over the next couple of
>days I will run that midi test.
Thanks for considering this.
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01-10-2010, 02:02 PM
Ralf Mardorf
MIDI timing
geoff wrote:
> On Tue, 05 Jan 2010 21:27:32 -0700, Gustin Johnson
> <gustin@echostar.ca> wrote:
> <snip>
>
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA1
>>
>> geoff wrote:
>>
>>> On Tue, 29 Dec 2009 18:49:16 +0000, geoff <ot0006@0x29a.org.uk> wrote:
>>>
>>>
>>>> Hi there,
>>>>
>>>> I seem to have a jitter issue with external MIDI timing.
>>>>
>>> Still stuck at ~30mS jitter.
>>>
>>> Booted with "hpet=force", and the kernel (and thus ALSA) found an
>>> HPET, but the timing stayed the same.
>>>
>>> At Ralf's suggestion, I ran up Win XP Home SP2, installed the latest
>>> MidiSport drivers, installed MIDI-OX and ran a loopback test.
>>>
>>> This relies on the accuracy of the MIDI-OX timestamping, but I seemed
>>> to be getting a consistent 5mS round trip from the USB interface.
>>>
>>> Which seems to indicate there's a software level incompatibility with
>>> USB MIDI (or at least, MidiSport USB MIDI) and 3.0b3.
>>>
>>> I'm looking for suggestions to ameliorate this situation.
>>>
>>>
>> something like
>> http://www.philrees.co.uk/products/thruunit.htm#v4
>> or
>> http://www.philrees.co.uk/products/thruunit.htm#v8
>>
>> I have never needed or used these sorts of things, but it may be useful
>> for you.
>>
>
> Thanks for the suggestion.
>
> I had a configuration similar to that in the early 90s. To prevent the
> "drummer" sounding increasingly drunk as more (high controller
> density) parts were added to the piece, I replaced it with a Unitor 8,
> an eight port MIDI interface of the period.
>
> It doesn't take much stacking on a single MIDI cable to bring that
> inebriation about, imho. Plus, you need a switch box for patch
> editing, which is a pita.
>
> <snip>
>
Any way, if you should decide to buy such a MIDI thru box, keep in mind,
that it's easy to build one yourself, if you should be able to solder.
>>> And can anyone describe their measured low-jitter external MIDI setup
>>> with at least 4 ports, please? (where low is < 10mS)
>>>
>>>
>> I have a total of 3 midi devices (a keyboard, BCF2000, and a synth).
>> I use the 2 ports on my Hammerfall. I also have a midisport 2x2 that I
>> have not used for years. If I get some time over the next couple of
>> days I will run that midi test.
>>
>
> Thanks for considering this.
Cheers,
Ralf
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01-10-2010, 02:02 PM
Ralf Mardorf
MIDI timing
geoff wrote:
> On Tue, 05 Jan 2010 21:27:32 -0700, Gustin Johnson
> <gustin@echostar.ca> wrote:
> <snip>
>
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA1
>>
>> geoff wrote:
>>
>>> On Tue, 29 Dec 2009 18:49:16 +0000, geoff <ot0006@0x29a.org.uk> wrote:
>>>
>>>
>>>> Hi there,
>>>>
>>>> I seem to have a jitter issue with external MIDI timing.
>>>>
>>> Still stuck at ~30mS jitter.
>>>
>>> Booted with "hpet=force", and the kernel (and thus ALSA) found an
>>> HPET, but the timing stayed the same.
>>>
>>> At Ralf's suggestion, I ran up Win XP Home SP2, installed the latest
>>> MidiSport drivers, installed MIDI-OX and ran a loopback test.
>>>
>>> This relies on the accuracy of the MIDI-OX timestamping, but I seemed
>>> to be getting a consistent 5mS round trip from the USB interface.
>>>
>>> Which seems to indicate there's a software level incompatibility with
>>> USB MIDI (or at least, MidiSport USB MIDI) and 3.0b3.
>>>
>>> I'm looking for suggestions to ameliorate this situation.
>>>
>>>
>> something like
>> http://www.philrees.co.uk/products/thruunit.htm#v4
>> or
>> http://www.philrees.co.uk/products/thruunit.htm#v8
>>
>> I have never needed or used these sorts of things, but it may be useful
>> for you.
>>
>
> Thanks for the suggestion.
>
> I had a configuration similar to that in the early 90s. To prevent the
> "drummer" sounding increasingly drunk as more (high controller
> density) parts were added to the piece, I replaced it with a Unitor 8,
> an eight port MIDI interface of the period.
>
> It doesn't take much stacking on a single MIDI cable to bring that
> inebriation about, imho. Plus, you need a switch box for patch
> editing, which is a pita.
>
> <snip>
>
Any way, if you should decide to buy such a MIDI thru box, keep in mind,
that it's easy to build one yourself, if you should be able to solder.
>>> And can anyone describe their measured low-jitter external MIDI setup
>>> with at least 4 ports, please? (where low is < 10mS)
>>>
>>>
>> I have a total of 3 midi devices (a keyboard, BCF2000, and a synth).
>> I use the 2 ports on my Hammerfall. I also have a midisport 2x2 that I
>> have not used for years. If I get some time over the next couple of
>> days I will run that midi test.
>>
>
> Thanks for considering this.
Cheers,
Ralf
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MIDI timing
.
