Difference between Hydrogen exports and Ardour's recording of Hydrogen tracks

I just noticed something odd and actually annoying :

when you export a drum pattern from Hydrogen into a wav file, you will get exactly what you hear when the pattern is played from Hydrogen.

When you directly record into ardour from the hydrogen track outputs, the result is definitely different : the sample tails are eaten!

To convince you, I did a very simple test using a ride sample. You can download the hydrogen direct export and ardour region export here :


Sorry for the waiting time (1mn) before the download becomes active, that’s the free option of rapidshare.com
If you know of a better web storage location, please tell me.

Anyway, this difference is not acceptable. Does anyone have an idea why ? Does it have something to do with jack transport ? I am using ardour 2.3 SVN, Hydrogen 0.9.4 SVN, jack SVN-v1133 (0.109.x), there is no FX on the tracks. The WAV files are at 96kHz, I hope it’s not an issue.

It certainly sounds like there is a reverb on the exported wav. Did you record directly from the track_out_#L and track_out#_R? Try recording from out_L and out_R, which are mixed within Hydrogen. That ought to be identical to what it puts in the wav. On the other hand, you’re using SVN. There might be a bug in Hydrogen that causes it to apply FX during export even when they’re turned down… or even “lie” about their presence. I can’t find a per-track FX control in there, it only seems to have 4 buses (= 4 plugins max) and a send knob on each track. I can’t be sure, as I only have Hydrogen 0.9.3. It was segfaulting, too… had to re-emerge while waiting on RapidShare to give me the second wav there :slight_smile:

Hey! thanks for the reply.

The hydrogen export has been done as follows :

  • create a simple pattern with ride samples
  • make a song with a few of this pattern
  • export the song to wav
    To my knowledge, there’s no effect whatsoever unless hidden, which I doubt.

The ardour export proceeded as follows :

  • create a stereo track and connect the hydrogen ride track outputs to it
  • record the hydrogen song in ardour
  • export the resulting region to wav
    No effect either.

I can try to redo it in a slightly different way, using the main hydrogen outputs instead.

OK, so instead of using the hydrogen track outputs directly to ardour, I used the main hydrogen outputs connected to ardour. The result is different, it sounds like the direct hydrogen export (the one that you identified as “reverbed”).

So somehow, hydrogen does some post-processing before the audio reaches its main output ports. This is definitely a “cheat” since there’s no effect plugged in anywhere from my part. This is therefore not ardour related so I won’t talk more about this here.

EDIT: just to let you know, I found the root cause in the hydrogen code. It applies a “low pass resonance filter” on the instrument data that goes to the main outputs but does not do that for the direct track outputs. I will modify the code to my taste and post a patch on the hydrogen forum if anyone is interested. I think that this “staccato” result sucks. In real life you have a minimum amount of resonance. I don’t want to overload ardour with that kind of crap for each hydrogen track, it shall come out right from hydrogen in the first place. It probably colors the direct track outputs but I don’t care.

Ahh, kudos for tracking that down (no pun intended). I was doing my own test by recording from the track and stereo mix simultaneously while tapping on the track’s play button, but I didn’t get to listen to the results more than twice-- I tried to set a loop range with the mouse and Ardour froze. :frowning: Before I went back to listen to the regions’ stored wavs, I got distracted by admin duties… I figured they were different, though, just from looking closely at the waveforms before then-- the one from the mixed output was just slightly louder. Good luck with your mod :slight_smile:

… I was too fast in my last update, does not look like it has anything to do with it after playing around with different code modifications … it’s getting late here, I will look at this at another time.

I’ve got a patch for Hydrogen that solves this track-outs problem. (See my post on the Hydrogen forum). If anyone is interested, post here or there and I’ll make it available.

The patch is here : http://homepage.ntlworld.com/fatgerman/Hydrogen/DrGPatch.html
It contains an option for having track outputs pre- or post-fader, and it has a fix for the sample cutt-off when using track outputs. The latter happened because the track outputs container (in the hydrogen code) were not global vars, they were reinitialized each time a new sample had to be played. Big thanks to DrG for having spent time in debugging and providing a patch this during his time-off! I tested the patch and so far, it behaves as expected.

Hello, I know this was posted a long time ago, but, can I get that patch from someone?

Do you really need it?
Since DrG apparently posted on the Hydrogen forum I’d imagine it was incorporated into the source. Have you tried the 0.9.4rc1?

Well…I have this problem with Hydrogen…when i output directly from each track (instead of Hydrogen out but rather Kick or Cymbal out) to Ardour the effects I am applying in Hydrogen do not get applied, but if i get the output from hydrogen mix out then the effects are applied.

Nothing against Hydrogen to say, maybe you wish like to try tapeutape, which can play any sample you have ? It’s not a drum machine, but everything is here, multisampling for level is working, MIDI complete using you can think about too… use it with Rosegarden, and it’s ok on MIDI#10. Sometimes crash, so store often and it will rock !!!


PS : no commercial here, I don’t know these guys, only for share !