Ardour and AVL Drumkits LV2 notes cut off

I did post this at Linux Musicians but it probably would have made more sense to post here in the first place…


I have not done a lot of MIDI work for many years but things are heading that direction again… Ardour has made a lot of MIDI improvements but I’m into a bit of a stumper…

I’m using my own AVL Drumkits that have been derived from the same sample sets… If I program MIDI drums in Hydrogen with the h2drumkit version or in energyXT with the SFZ version the drums all play back and sound exactly as you would expect. If I import the MIDI file from either Hydrogen or energyXT into Ardour and then load up the AVL Drumkits LV2 Plugin that corresponds to the kit I used then the cymbals (both ride and crash) are played back truncated and the hihats and other percussion sound a bit truncated as well… The kick, snare and toms sound normal this happens whether I select percussive mode or sustained mode… What is going on?

In a dusty cupboard in the back of my brain I recollected something about MIDI ‘note-off’. So I tried the x42 MIDI Event filter and told it to block MIDI note off and voila the crash cymbal hits once again sounded normal but the ride tip hits and hihats still sound pulse-y and weird so the issue must not be 100% MIDI note off. Why should I have to do this in the first place though when these MIDI files all work perfectly as programmed in their original programs. Before I tried the MIDI Event Plugin I was needing to stretch out crash cymbals to 6 or more full beats to make them play completely in Ardour, in Hydrogen and energyXT it seems there is no direct relationship between the programmed note length and the sample playback, why would there be in Ardour…?

I’m no MIDI expert and it’s never been my forte but it seems to me that the file should be played as programmed in any DAW you put it in. The AVL drumkits samples are all one-shot samples, one difference is that the AVL Drumkits LV2’s use SF2 (soundfont2) files but all of the sample settings were inherited from the SFZ settings.

Any MIDI experts here that can shed some light, I’m kinda tearing my hair out here as I have a lot of completed drum tracks I was hoping to simply import, load up the LV2, fan out and be done with it. I did not foresee this as being an issue.

I will happily share the MIDI files if anyone wants to test or try them.

1 Like

I believe this is just a display/editing mode. I don’t think it makes any difference to the playback.



1 Like

I would suggest that it may be a consequence of the specific rendering engine that the samples are being played back in.

As I understand it, roughly speaking, MIDI instruments have something like an ADSR envelope which dictate what happens to the sound at the commencement of the note (note-on) and during the playback of the note, with respect to any subsequent note-off event.

Typically with a conventional non-percussive instrument, such as a keyboard synth, the attack starts at the note-on, followed by the decay and sustain which then continues until the note-off event, which then triggers the start of the release.

Percussion instruments will, typically, have a more rigid rendering definition than a synth, but will probably be based on the same principles as, fundamentally, they are no different from other instruments as far as MIDI is concerned.

One would expect, for instance, that many percussive instruments wouldn’t have much, if any, of a sustain, moving directly through attack, to decay, and release. Others, like ride cymbals, probably should have a sustain element.

The question seems to be: how is this implemented in each of the rendering engines?

If, for instance, the release part of the note isn’t properly implemented (maybe due to how the sample is mapped) then a note-off event may well choke the sound short.

The way to test this, of course, would be to connect a MIDI keyboard to AVL Drumkits and experiment with pressing the keys for different durations.

I have no idea what this could be.

Of course, I may be well off the mark here. I wouldn’t mind getting a copy of the MIDI file so I can have a look and a listen myself.



1 Like

I have edited the .sf2 for Black Pearl and Red Zeppelin and add exclusive groups for cymbals and hi-hat, and marked the samples as percussive, so note-off does not affect them.

I have not done that for the Blonde Bop kit, and took the .sf2 from you as-is.

1 Like

I didn’t know that was a thing. You learn something new every day. Is that within the soundfont definition?



PS. I cannot reproduce this.

I tested playing a very short Crash 1 (Note 49, C#) with the Blonde Bop Kit. MIDI Note On → Note Off is just 4 audio-samples and yet the Sound keeps ringing for about 6 seconds.

It also looks like the sf2 is set up correctly. Cymbal volume envelope is set to 100 sec (a bit overkill), and the Exclusive class is also set:

That explains why it works just fine here. Can you provide a session that causes the issue?

You can specify a AHDSR envelope for any given sample. So one would set hold to the length of the sample. Here it seems Glen just used a very long release time, which is also fine.

1 Like

Ahhh, well I did do the mute groups in the SFZ’s but other than making them ‘one-shot’ I did nothing else. I created the SFZ’s and converted directly from SFZ–>SF2 with Polyphone and sent them to you. I was not aware that there was another step to make them ‘percussive’ in the SF2 spec. :thinking:

I leave the cymbals very long otherwise they don’t sound natural especially in stops or song endings

1 Like

Apparently the sfz → sf2 conversion did that, by adding very long release times.


There should be another change now that it’s being discussed…

Ride Bell should be taken out of the Ride cymbal mute group (4)… Drummers use the bell on offbeats and the way it is now any tip samples are killed on even beats and it sounds bad…

It was a mute group decision I didn’t think through…

Off topic (sorry) but, @GMaq is there any specific reason these kits only have two toms? Most of the drum kits I encounter have 3 toms.



Essentially because that is what is at hand…lol

4 piece kits were kind of a thing that many drummers returned to in the 90’s and we both play 4 piece kits here and the influences are largely blues, roots, americana and indie which are usually 4pc kits…

Only our Black Pearl Kit even has a second rack tom…

1 Like

The better the drummer, the fewer toms they have in their kits. Usually zero these days.

@GMaq Could you upload a session that has this issue?


Here is the worst offender MIDI file exported from energyXT, it was programmed at 150BPM using the Blonde Bop HotRod SFZ

Here is one exported from Hydrogen… 98BPM using the Blonde Bop regular. The crashes work OK but the ride cymbals sounds weird even in places there is no ride bell…

OK that has concurrent pedal and closed HH events, which are currently exclusive.

It seems the ride-tip sample is re-triggered every time it is hit. If I stop playback in the middle, it keeps ringing.

I wonder if the issue at hand is voice stealing. Since the sf2 uses a 100sec decay, and avldrums.lv2 is configured to only have a polyphony set to the the number of kit-pieces (26).

But did you also notice the first ‘I Agree’ MIDI file has very truncated crashes/rides…?

No. They keep ringing here. Here’s a quick export with Crash2 hit.

I’ve spent decades thinking Terry Bozzio was a real good drummer.
Guess I was wrong then :grinning:


OK, after work I’ll do a screen cap of what I’m seeing here, gotta run for a bit…

Thanks very much for looking into this!

kids these days:

1 Like