I got between 35 and 40 ish. Surely it's going to be >10, anyway, because of the delay.
----- Original Message ----- From: "jfm3" jfm3@ouroboros-complex.org To: pd-list@iem.kug.ac.at Sent: Thursday, March 06, 2003 12:17 AM Subject: [PD] midi latency test
If you have some time, please connect your MIDI in to your MIDI out and bang on the attached patch. Let me know what number you get. I would expect this number to be very low; around 1. On my systems it is very high, and I'm not sure why.
-- (jfm3 2838 BCBA 93BA 3058 ED95 A42C 37DB 66D1 B43C 9FD0)
Well, I was going to actually cable this up, and then I realized that it's not so easy with the standard soundblaster MIDI adapter I'm using, since it doesn't provide female sockets, but instead, male cable ends. So in my case, I can't just take a MIDI cable and connect the input to the output!
So jmf3 and PT147, are you really talking about hardware MIDI, and if so, I take it you both have a MIDI interface card other than the soundblaster adaptor? If not, the how did you do it? Yes you can pass it through the Input and Through ports on a synth, but I think that first you would want to make sure that the "thru" port is really a hardware circuit connection, and not implemented in software in the synth.
If you _are_ really talking about MIDI, and not software emulation of it within the PC, then even so, 35 to 40 ms seems a bit long (these are ms values, right?).
PT147, you say that it's going to be more than 10. If this is milliseconds, I'm not so sure why that would be normal, because a complete MIDI message should go through the interface in about 1 ms. So any delay much greater than this should be due to the operating system and it's drivers. Am I missing something? Unoftunately, neither PT147 nor jmf3 said what OS they are running on. I have the feeling that this is where the problem lies. jmf3, what do you mean by "very high"?
Regards
Larry Troxler
On Wednesday 05 March 2003 21:29, PT147@mdx.ac.uk wrote:
I got between 35 and 40 ish. Surely it's going to be >10, anyway, because of the delay.
----- Original Message ----- From: "jfm3" jfm3@ouroboros-complex.org To: pd-list@iem.kug.ac.at Sent: Thursday, March 06, 2003 12:17 AM Subject: [PD] midi latency test
If you have some time, please connect your MIDI in to your MIDI out and bang on the attached patch. Let me know what number you get. I would expect this number to be very low; around 1. On my systems it is very high, and I'm not sure why.
-- (jfm3 2838 BCBA 93BA 3058 ED95 A42C 37DB 66D1 B43C 9FD0)
PD-list mailing list PD-list@iem.kug.ac.at http://iem.kug.ac.at/cgi-bin/mailman/listinfo/pd-list
Do MIDI In jacks still use opto-isolator components? I think they did in the original spec... The rise- and fall-times could account for the added delay perhaps?
Larry Troxler wrote:
Well, I was going to actually cable this up, and then I realized that it's not so easy with the standard soundblaster MIDI adapter I'm using, since it doesn't provide female sockets, but instead, male cable ends. So in my case, I can't just take a MIDI cable and connect the input to the output!
So jmf3 and PT147, are you really talking about hardware MIDI, and if so, I take it you both have a MIDI interface card other than the soundblaster adaptor? If not, the how did you do it? Yes you can pass it through the Input and Through ports on a synth, but I think that first you would want to make sure that the "thru" port is really a hardware circuit connection, and not implemented in software in the synth.
If you _are_ really talking about MIDI, and not software emulation of it within the PC, then even so, 35 to 40 ms seems a bit long (these are ms values, right?).
PT147, you say that it's going to be more than 10. If this is milliseconds, I'm not so sure why that would be normal, because a complete MIDI message should go through the interface in about 1 ms. So any delay much greater than this should be due to the operating system and it's drivers. Am I missing something? Unoftunately, neither PT147 nor jmf3 said what OS they are running on. I have the feeling that this is where the problem lies. jmf3, what do you mean by "very high"?
Regards
Larry Troxler
On Wednesday 05 March 2003 21:29, PT147@mdx.ac.uk wrote:
I got between 35 and 40 ish. Surely it's going to be >10, anyway, because of the delay.
----- Original Message ----- From: "jfm3" jfm3@ouroboros-complex.org To: pd-list@iem.kug.ac.at Sent: Thursday, March 06, 2003 12:17 AM Subject: [PD] midi latency test
If you have some time, please connect your MIDI in to your MIDI out and bang on the attached patch. Let me know what number you get. I would expect this number to be very low; around 1. On my systems it is very high, and I'm not sure why.
-- (jfm3 2838 BCBA 93BA 3058 ED95 A42C 37DB 66D1 B43C 9FD0)
PD-list mailing list PD-list@iem.kug.ac.at http://iem.kug.ac.at/cgi-bin/mailman/listinfo/pd-list
PD-list mailing list PD-list@iem.kug.ac.at http://iem.kug.ac.at/cgi-bin/mailman/listinfo/pd-list
On Wed, 5 Mar 2003, Greg Rippin wrote:
Do MIDI In jacks still use opto-isolator components? I think they did in the original spec... The rise- and fall-times could account for the added delay perhaps?
Not possible. 1 bit at midi rate is 1/31250Hz = 32 microseconds The rise- and fall-time of this optocoupler should be a fraction of that.
I also heard the myth more than once that there is a substantial delay between midi-in and midi-thru ports. There is a delay from midi-in to midi-out or a 'soft' midi-thru, because the midi-commands are parsed before thay're retransmitted. A dedicated midi-thru is just a signal buffer.
j#|@
On Thu, 6 Mar 2003 16:45:20 +0100 (MET) Johannes Taelman Johannes.Taelman@rug.ac.be wrote:
On Wed, 5 Mar 2003, Greg Rippin wrote:
Do MIDI In jacks still use opto-isolator components? I think they did in the original spec... The rise- and fall-times could account for the added delay perhaps?
Not possible. 1 bit at midi rate is 1/31250Hz = 32 microseconds The rise- and fall-time of this optocoupler should be a fraction of that.
I also heard the myth more than once that there is a substantial delay between midi-in and midi-thru ports. There is a delay from midi-in to midi-out or a 'soft' midi-thru, because the midi-commands are parsed before thay're retransmitted. A dedicated midi-thru is just a signal buffer.
I've built a pc-joystick-port to midi box, and at least in my version the midi thru was directly wired to the midi in, giving almost exactly zero latency (factoring in the movement of electrons through copper wire media).
Chris. _________________________________ chris@mccormick.cx http://www.mccormick.cx http://www.sciencegirlrecords.com
On Fri, 7 Mar 2003 09:35:26 +0800 Chris McCormick chris@mccormick.cx wrote:
On Thu, 6 Mar 2003 16:45:20 +0100 (MET) Johannes Taelman Johannes.Taelman@rug.ac.be wrote:
On Wed, 5 Mar 2003, Greg Rippin wrote:
Do MIDI In jacks still use opto-isolator components? I think they did in the original spec... The rise- and fall-times could account for the added delay perhaps?
Not possible. 1 bit at midi rate is 1/31250Hz = 32 microseconds The rise- and fall-time of this optocoupler should be a fraction of that.
I also heard the myth more than once that there is a substantial delay between midi-in and midi-thru ports. There is a delay from midi-in to midi-out or a 'soft' midi-thru, because the midi-commands are parsed before thay're retransmitted. A dedicated midi-thru is just a signal buffer.
I've built a pc-joystick-port to midi box, and at least in my version the midi thru was directly wired to the midi in, giving almost exactly zero latency (factoring in the movement of electrons through copper wire media).
I just had a look at the circuit diagram and I should clarify that it's buffered by the opto device first.
Rgds,
Chris. _________________________________ chris@mccormick.cx http://www.mccormick.cx http://www.sciencegirlrecords.com
On Thursday 06 March 2003 10:45, Johannes Taelman wrote:
On Wed, 5 Mar 2003, Greg Rippin wrote:
Do MIDI In jacks still use opto-isolator components? I think they did in the original spec... The rise- and fall-times could account for the added delay perhaps?
Not possible. 1 bit at midi rate is 1/31250Hz = 32 microseconds The rise- and fall-time of this optocoupler should be a fraction of that.
Really. This is an interesting kind of MIDI "Urban Legend" (qouted because I'm obviously misusing the term, since this has nothing to do with whether we are urban per se).
It would be interesting to find a story about how this got started.
I also heard the myth more than once that there is a substantial delay between midi-in and midi-thru ports. There is a delay from midi-in to midi-out or a 'soft' midi-thru, because the midi-commands are parsed before thay're retransmitted. A dedicated midi-thru is just a signal buffer.
j#|@
Yep. Agreed. I just wonder if too save a few cents in hardware, if commercial synths still typically implement midi-thru as a direct hardware connection? I don't know, I should take a look at the manuals for my synths and see if they do. I suppose as I think about it, if a synth has a seperate thru and out port, then probably very little if anything in hardware costs would be saved by emulating the thru port in software.
Larry
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Chris McCormick -
Greg Rippin -
Johannes Taelman -
Larry Troxler -
PT147＠mdx.ac.uk