MIDI timing in Reaper

OK and thank you. How about that tricky MIDI-interface which once came from Emagic? I am still using it. 8 ports, I guess its called ATM-8 (Advanced time management) or something. The trick of that device (as far as I remember): To keep latency low it will accept MIDI events before they should actually be fired. But it keeps the timestamp in mind. So it is (thereotically) able to fire on all ports (and channels) at the SAME time and overcoming latency of some kind (i.e. caused by the serial transportation protocol for the 16 channels per port or the windows jitter you mentioned). Will it's driver take care anyway? Will it be configurable to take full advantage of it?

Reaper always streams the MIDI events to the device at the start of the audio block during which they are meant to be played, in other words, there is a slight amount of send-ahead. In most cases that doesn't do much for latency though, if the device needs additional time to process the MIDI events, that's additional latency.

Will the very informative first post, (and similar posts) find a way in the Reaper manual, or some sort of accessible online help? It's a shame to see threads like these get lost over time.

thanks schwa, excellent summary on the topic! FWIW, from my experience reaper is in the same "jitter league" as samplitude and cubase when recording sequenced HW synths (but me ignoramus thought that this has to do with clock issues of the interface).

Many thanks for the good explanation Schwa.. the MIDI does appear to be tighter on my system.. IE Recording the audio of a midi click track sent from Reaper (reaper MIDI->Device->Audio->Reaper) is to within 3 MS. I think you guys may have cracked it...I hope it stays there like that. oh to have MIDI pass thru (0 Latency).. Excellent job.. I am enjoying reaper more and more.

Where do you set "low-latency mode"? Or is "low-latency mode" synonymous with a low buffer size on your audio device?

Let's heard the forum combat kids out in to their own play pen. Relax and stay on topic lads. On topic, I've sent every midi citizen I know to this thread for the information you folks provided. I also agree this information should be part of the manual. Most folks will assume that's where they'll find out about accurate Reaper and midi devices can be. This will help to reassure them, i.e. remove doubt and uncertainty(which I call fear and ignorance) about this subject.

Is there a way to find out if the driver is using QPC?

That's a saucy bit of program, isn't it. I believe the app is simply telling you to use QPC timestamps. Apparently in Cubase you can only use QPC timestamps with DM or emulated DM ports, but in Reaper you can use QPC with the normal Windows MIDI port.

Ok, thanks!