Sorry I did not mention my set up. I supposed this aspect of Ardour configuration was a generic question relevant to nearly all installations. I am using Ardour 6.2 on Fedora 31 with ALSA sequencer mode.
Yes, that’s right. I have a direct connection between my keyboard controller and my sound module synthesiser. This has approximately zero latency. I can make such a connection in several ways, such as using the qjackctrl patch bay or installing old 5-pin DIN midi cables and thru boxes. Also, if I had a standard MIDI keyboard synthesiser with internal connection between the keyboard and sound module parts, I’d surely be in the same situation? I wouldn’t want Ardour echoing everything I play after a few milliseconds or so.
I notice the thru behaviour stops when the channel is muted, so this is one work around: press mute before tracking some MIDI notes, and the unmute for playback. It’s a bit longwinded. Yes, it is armed as I recall. The MIDI connections are input from a USB Midi master keyboard and output to a another device: so both input and output are through ports listed in the ‘hardware’ division of Ardour’s MIDI patching window, rather than there being a softsynth instantiated within Ardour’s effects strip for the channel.
I do have a follow-up question as well, if you’d be so kind. I’ve been exploring the latency settings on the MIDI aspects of Ardour by performing various connections, such as recording the output of a 5-pin DIN connection on an audio input and recording (printing) the audio output of a Yamaha Motif controlled by USB midi. From this I’ve discovered that even with zero output advance on my MIDI output connection, the MIDI signal is 56 samples (1ms or so) too early. I attribute this to the default audio calibration, which by default, partitions the audio round trip precisely in two. So if I offset this partitioning, by moving 56 samples from one side to the other, I think it will be perfect. So that’s no problem. But on the MIDI input side, the amount of timing correction I need to apply seems to be a long way removed from what the ‘calibrate’ button on the MIDI Devices page suggests. Specifically I need to manually add on the “Buffer size” setting from the Audio/MIDI set up page. I presume this is a minor bug in this version of Ardour that simply fails to add this on. I am operating with Periods=2.
Many thanks - David Greaves