Hi to all, this is my first post in this forum.
I'm trying to use PD's patches inside my setup, and now I'm struggling with the MIDI latency that PD creates.

First of all, I'm a drummer and I use a drumpad(DrumKat) to trigger samples on my laptop, so for me the latency is a 1st class problem.
I have two setups: one with Ubuntu 10.04(Kernel 2.6.33-29-realtime) + jack, and the other with OSX leopard + jackosx. The first one is the more tested.

I want to know the latency that PD creates between notein-noteout process.
To do this, I simply connected my drumpad to PD's midiin, PD's midiout to PD's midiin, and opened my patch(attached to this post).

If the patch is right, there is a link between jack's latency and PD's MIDI latency.
If I set jack's framebuffer to 256, I have 11.6 msec of audio latency and 5.8 ms of PD's MIDI latency.
If I set jack's framebuffer to 128, I have 5.8 msec of audio latency and 2.9 ms of PD's MIDI latency.

Is this correct? Is there a way to reduce MIDI latency without changing the audio latency of jack?

Thank you and sorry for my english.

Nicola

http://www.pdpatchrepo.info/hurleur/pd-midi_latency_test.pd

MIDI out in Pd is synced with the audio output buffer. I'm not entirely sure why this is. I think it is meant to allow external synths to sync up correctly with Pd's audio, but I don't really think this would work unless it's an analog synth, and I don't think it's worth it. And it doesn't matter if you have DSP on or off.

But anyway, to reduce the latency you'll need to reduce Pd's latency in the audio settings dialog as low as you can get it. If you're just doing MIDI processing (i.e. [notein] -> process -> [noteout]), you can run that in it's own instance of Pd and reduce the audio buffer to a minimum. Then have the audio stuff in its own instance.

As far as I know, this is only an issue with MIDI output. I don't think it's an issue with input, so if you're just triggering audio in Pd with MIDI and aren't sending MIDI events out, it shouldn't be something to worry about.

Thanks! This is exactly what I needed to know. I tryed the two instances of PD and it worked great.

Hello, I'm having a similar problem but can't find latency anywhere in Pds audio settings.

I've got a MIDI keyboard triggering samples in buffers. So there's a [notein] taking MIDI notes which are assigned with a [sel 1 2 3 4 etc] object to buffers which have little samples for each key in.

There is a considerable delay between pressing the key and hearing the sound.

I've also got a [key] object for using the computer keyboard to select the different sounds that go in to the buffers and there's an even larger delay between pressing the key and the sound changing.

Help!

Oh I'm using windows xp I should probably say

Media -> Audio Settings -> delay (msec)

Perhaps you were hoping for latency compensation?

I find 20ms the threshold for suitable keyboard playing.

Yeah I changed that but it won't stay changed. I put in a new value and press apply and ok but then when I open it again it's gone back to the original value. Grr!

Help!

Look at the flossmanual and use startup flags (err -audiobuff 20 ?) to set your latency.

And get Jack, though I don't know much about PD on windows other than that some people have reported impressively low latencies. Search the forum.

oh wooow, thanks, I struggled for months with the default latency, and I blamed the wifi connection... (using pd with touchosc and an ipad). set it to 1ms with audio off, works perfectly.

Nope, setting delay to 20 does make the latency a bit better but destroys the quality of the audio, making it sound almost as if it's been shredded.

??

You'll have to use ASIO drivers if you're on windows. also make sure you hit "save all settings" before you hit apply and ok. If it still doesn't stick, then use the startup flags.

I have asio drivers installed but they can't be selected anywhere as audio outputs

found the answer here
http://booki.flossmanuals.net/pure-data/getting-started/configuring