Hydrogen as JACK timebase slave - can't play drumkit freely

[ttshaw1]

I'm noticing some weirdness when I try to use Ardour as the JACK timebase master. When JACK is not connected, is the master, or is "out of sync", Hydrogen works independently. I can play a song or loop a pattern and use my MIDI synth to add drums on top of it, with or without recording them.

But when Hydrogen is slaved to Ardour and they're "in sync", Hydrogen's MIDI-In LED lights up when I press a synth key, but I don't get any audio out. It also sounds like the drum track is doubled. It's certainly much louder. Sample attached; in the first part, Hydrogen is in sync. In the second part, it's out of sync.

Take8_Drums-1.1.mp4

To clarify what I mean about in vs. out of sync, I can have Ardour playing and dictating the time with Hydrogen in song mode, but if I switch to Pattern mode, Play, then back to Song and Play, they're out of sync and hydrogen doesn't care what's going on in Ardour. There are other patterns of messing with Pattern/Song mode and Play/Stop that will desync them.

I don't want to file this as an Issue because I might be misunderstanding something, being new to this software. Is there a way to have Hydrogen be the slave in song mode and still be able to throw in additional drums on top of what's being played? Is the doubled drums normal? Would it be better to use Hydrogen as the master as suggested here? That feels unnatural to me because I see Ardour as the center of the setup - everything should eventually feed into Ardour.

[theGreatWhiteShark]

Is there a way to have Hydrogen be the slave in song mode and still be able to throw in additional drums on top of what's being played?

Ideally this should work out of the box. But JACK Timebase is, unfortunately, not a good standard. It has massive loop holes, like not being able to handle tempo changes properly (be aware of that) and due to a missing reference implementation or test suite there are various sorts of little bugs in a lot of client applications. Those in Hydrogen I tried to tackle for the upcoming release in #1977.

Could you check whether you have to same issues using this version? (It corresponds to the latest commit of branch releases/1.2 in case you prefer compiling it yourself)

Would it be better to use Hydrogen as the master as suggested here?

No. Both modes should work. If not its a bug and we will (try to) fix it. That said, Master mode tells Hydrogen not to listen to external time signals and to just send them. There is a lot less things that could go wrong in there. But again, non-Master should work too.

Un-check “Ardour is JACK Time Master”.

This is one of the little things that make JACK Timebase really hard to support. When checked (at least at the time I read their code for debugging) Ardour won't be Timebase Master at all times. This is not how this protocol works. It only makes Ardour discard external time signals (and maybe tells it to periodically attempt to register as master again).

That feels unnatural to me because I see Ardour as the center of the setup - everything should eventually feed into Ardour.

Yes. That's how I would use it too.

[theGreatWhiteShark]

The red outline around the CPU bar does go away after a second or two.

This indicates a so-called XRun event. Meaning the audio engine was not able to process its audio in time and JACK discards the content of Hydrogen's audio buffer for that processing cycle.

I've found Ardour to be pretty stable on my setup.

NIce. I by no means want to discourage its usage.

If you want to try to reproduce my setup, here's a list of the packages I've installed. Dependencies aren't shown but Arch's package manager is smart enough to grab them if you install the list.
packages.txt

Thank's a lot. I'll do in a couple of days.

Are you aiming to have the code for v1.2.4 frozen in the next few days?

No. I mean, the sooner the better. But we are in not in a hurry and quality and stability is a lot more important for us. In addition, I'm currently working on another issue for 1.2.4 as well.

I can put in a half hour here and there on weeknights, but I may not be able to really dig deep until the weekend.

Similar for me. But I have less time during weekends :D

[theGreatWhiteShark]

If you want to try to reproduce my setup, here's a list of the packages I've installed. Dependencies aren't shown but Arch's package manager is smart enough to grab them if you install the list.
packages.txt

Thank's a lot. I'll do in a couple of days.

What's up with Arch Linux? Haven't used it in a while. They do not feature a graphical installation anymore? One has to write a wpa_supplicant configuration by hand and start it as a background process when just having a single shell? Oh boy, even Void Linux has a better UX. 😆 But anyway. I can't get it to run on my second laptop as its WLAN is not properly working with their shipped kernel. I'll try with a different Linux audio distribution which comes with a preinstalled Ardour in a couple of days.

[ttshaw1]

I installed something like a couple years ago and it's definitely a slog to set up. I can't remember if there was a GUI at the time but I opted to stick close to the Arch Wiki install guide, which is all command line. From what I can remember, going through the critical steps here was enough to get the computer functional enough that when I installed KDE Plasma, everything else was easy to set in a GUI. But I think I was working from home at the time, so god knows how many hours it took to actually do that.

If you can get the info you need if I run an AppImage with logging please do send one over. I imagine the total man hours with that approach will be something like 10% of what it will take for you to get a working Arch install up.

[theGreatWhiteShark]

Don't worry. We just have to deal with JACK and an another JACK client in here. Other distributions should yield the same results. I just set up a new AV Linux machine with Ardour running.

First thing I noticed is that Ardour does neither send JACK positions nor does it start/stop JACK transport out of the box. In the upper left part there is a button reading Int.. Right clicking it allows you to select JACK as "Transport Master". Close the dialog and click the Int. button until it turns green and displays JACK. Now Hydrogen should pick up transport immediately.

[ttshaw1]

@theGreatWhiteShark sorry I didn't get back to you. I somehow had the misconception that there was something you were looking into and the ball was in your court, and I managed to neglect looking at this thread for ages. Turns out, you're completely correct, Ardour was set to use a MIDI Timebase. With Ardour set to JACK Transport Master and Hydrogen set as JACK Timebase Controller, things are working smoothly. Moving the playhead in either program moves it in the other, and play/pause in one program also plays/pauses in the other. Thank you so much for your help. I'm including screenshots in case anyone else runs into this in the future.