Thanks for the responses Ralf, they've pointed me in the right direction :)

What solved this for me was setting the queue timer resolution to "system timer (1000Hz)". When I switch to "HR timer (1000000000Hz)" , which I presume is the default, the system locks up after a short play time - even in the first bar! I'm not surprised this is what was causing issues - a billion Hz is gigantic! Surprised any computer can send MIDI signals that fast.

Would someone be kind enough to explain (or link to an explanation of) what exactly this setting affects, and what the other settings "PCM capture" etc do? I have a vague idea looking at the name, but I'd like to know for sure.

To test stability, I've just left the sync running for 2773 bars, at 120bpm! This included lots of pause/play spamming on both the synced device and inside qtractor, along with some recording. No hiccups :)

You may also be pleased to know that sync actually seems to be working marginally better than in Ardrour! For some reason in Ardour (might be a setting), the playback doesn't start with a play, but a pause THEN play. Qtractor works as you'd expect :)

I actually like the portability of storing patterns on hardware - until my RY10 decides to forget them all that is! Worse still, backup is to cassette tape only.....

I still adore the thing :P

---- On Thu, 07 Aug 2014 22:32:12 +0000 Ralf Mardorf <> wrote ----

On Thu, 2014-08-07 at 22:43 +0200, Ralf Mardorf wrote:
> The only issue seems to be, that the RX21 only follow song positions,
> when playing or manually moving the play head, but in loop play it's
> ignored.

I suspect that song position pointer only is send when the play head is
moved to a position and when starting, but during playing just MIDI
clock is sent. I didn't check this, but if so, for loop play it should
be send each time the loop is at the left locator position.

> Qtractor as sync master and a YAMAHA RX21 as sync slave (both tested,
> RX21 CLOCK: INTERNAL and CLOCK: MIDI) seems to work correctly.

With clock set to internal, song position pointer does work, for correct
sync there likely is the need to choose MIDI ;). JFTR syncing different
MIDI gear to each other is a PITA, for some devices combinations it does
work and for other devices combinations it doesn't work. It has nothing
to do with bad software and/or bad stand alone devices, it's related to
the MIDI specifications, we once talked about this at LAD or perhaps
LAU. If Qtractor does freeze a machine it's a bug, but as already
pointed out, I don't experience this bug on my machine.

IMO using a sequencer is more comfortable, than using menus of drum
machines, so using a drum machine as a MIDI drum sound player IMO is
better, than to sync the machines sequencer with the computer's

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