Skip to Content

Hydrogen on the Raspberry Pi

1 reply [Last post]
Raptor Ramjet
Offline
Joined: 06/03/2016

Hello,

I've just bought a Raspberry Pi 3 along with a 7" touchscreen and case.  One of the main reasons for doing so is that I think by installing Raspbian and Hydrogen this would make a superb little drum machine.

Unfortunately after trying this out it's been a bit of a failure as the audio output from Hydrogen is terrible.  Loading one of the demo patterns (even one of the simpler ones) produces output sound which can only be described as distorted, slow and stretched.  It sounds very much like a sample playback rate mismatch (i.e. as if you'd used an old 12 bit sampler to sample a sound then played it back a few keys down from the original pitch but with the additional problem of a slightly "crackly" output jack)

Having run xmms2, LXMusic and "aplay test.wav" on the pi these all produce excellent quality output so I think that the problem looks very likely to be that I just need to configure Hydrogen or the sound system in some way.

So I tried swapping the audio engine around (i.e. using "default", "alsa" or "jack") and have found that jack gives the best results but even if I switch sample rates between 48000, 44100 and 22050 I still get the distorted sound.

Running "hydrogen&" from a terminal also shows that whilst starting up the program suffers a large number of xruns and also large numbers of XML parsing errors when loading the kits.  If I also run qjackctl this shows a load of about 12% and doesn;t show any xruns whilst Hydrogen is playing.

So if anyone has any good tips as to what I might be able to do to fix this I'd be most grateful ?  I've also asked this question on the Raspberry Pi forums as I'm not sure if this is more likely to be a Pi or Hydrogen problem.

But an additional problem with this "HydroPi drum machine" idea is that the main screen of Hydrogen is too large for the 7" touchscreen.

Assuming that the audio problem can be fixed I would also therefore like to ask if it would be possible to introduce a "live playback control screen" especially for use on the Pi ?  e.g. a form which would take up the whole of the 7" touch screen and would allow you to load either songs or patterns that you'd previously prepared and then play, start, stop, forward or rewind them etc.  Being able to choose patterns/songs from a small list would also be excellent.

If this left room to have a small sequence row to allow some basic pattern entry (or live muting/unmuting of parts) that would be perfect !

Obviously you could then prepare your songs/patterns on eother another machine or by plugging the Pi into a larger monitor via it's HDMI output but for ive playback you'd be able to run the whole thing from the touchscreen.

All in all I think the Pi, a touch screen and Hydrogen would make an absolutely superb drum machine.  Given the Pi has a 1.2Ghz quad core processor and CPU it must be up to the task ?  I bet my old Kawai R50 drum machine has about a 16Mhz CPU and 1Mb of RAM and it still sounds great today (in a lo-fi way of course)  But a "HydroPi" machine would be even better than things such as the Korg Volca sample as you would actually have a decent amount of memory to store user patterns !!!

Just a thought.

olinuxx
Offline
Joined: 04/17/2010

Hi,

about the screen resolution issue, have you tried : menu -> tools -> preferences -> Appearance -> Default interface layout : select "tabbed" ?