I am developing for the project Zynthian. Zynthian is a modular software synth based on Raspi and famous engines like ZynAddSubFX, setBfree, Fluidsynth and others.
Currently we are using Hifiberry soundcards but the pisound looks very promising for more functionality . Especially the line in would be a very nice feature - so we can use vocoders, effects for guitars and voice, …
I hope I cn get a pisound as fast as possible because we would like to use it for our showcase on the next Maker-Faire in Berlin.
last week I got my (beta) pisound: very nice! I asked a friend to print a 3D-case. For the beta I had to fix the MIDI holes and add a hole for the power plug (all done by hand and not inside the STL). Now my RPi3 with pisound fits into the case:
I created a SD card image based on our build scripts for Zynthian. This image fits onto a 4GB SD card.
This image is based on MOD-UI - a fantastic web based user-interface and LV2 host from [MOD devices]
(http://moddevices.com) and other fine open-source software. I and MOD are not responsible for any problems or
failures of the software! If you find bugs, you can try to contact me in this forum - but my main focus is creating
Zynthian and testing for MOD - so I cannot maintain this image. If you like MOD-UI and need support: think about
buying a MOD-Duo.
Wow, thanks for this nice surprise! We have also started playing around with mod-host/ui, it’s really an amazing piece of software. I will test your build in coming days! And sorry for not warning you about the case…
No problem! The case fits after some small additions
I have noticed a little “problem” - or let me say a difference between the normal Zynthian installation (RPi3 and Hifiberry DAC) and the MOD_pisound. My test pedalboard is the setbfreak-chain: setbfreak is a setbfree hammond organ setup but I made additional LV2 controllers for realtime controlling parameters via MIDI (and that’s why it is called setbfreak).
The setbfreak-chain is a pedalboard which consists of
The whirl uses much CPU time. On the Zynthian it works without dropout/digital distortion (even on a RPi2+Hifiberry-Zynthian). On the MOD_pisound I got very fast digital distortion. The base is the same Kernel and the same jack2 (with the same options) and I used the performance-schedular for the CPU on both machines.
Maybe a (optimization-)problem with the kernel-driver for the pisound? I wll try to check this the next days - perhaps I can make some demo sounds…
I am using the pisound MIDI ports. The distortion happens when pressing more keys. The setbfreak has to generate more tones and due to the high CPU level (whirl-speaker) it seems that the distortion occurs at hight load. Strange is, that der are no xruns reported from jack2…
That seems to be a difference between Zynthian/Hifiberry and pisound: For Zynthian we are using the serial device of the RPi and ttymidi as “user-space-driver”. It seems that pisound has its own MIDI device, or am I wrong?
BTW: Which GPIOs are used for pisound? For integration into Zynthian we need much GPIOs for TFTP and rotary encoders.
I’m not sure which setBfreak synth you have tested with, I have tried ‘setBfreak Tonewheel Organ’ but even before the sound reaches pisound, it usually has corruption at the hit and release of a MIDI note. The difference between HiFiBerry DACs could be different sampling rate (pisound runs on 48kHz instead of 44.1kHz), so the plugin may be behaving unexpectedly? The issue I observed though reproduced also when Jack was running using 44.1kHz sampling rate.
Anyway, I have captured the jack’s audio output using jack_capture, and found that having plugged in just the setBfreak Tonewheel Organ in MOD, it produces corrupted audio, before it reaches the sound card. In the Audacity’s screenshot below, I have marked the weird waveforms.
Ahh - ok. I will try to use 48kHz for jack. The plugins are independent of the sample rate (in fact they are getting the samplerate as a initialization parameter).
Ahhh! Yes - jack-capture or jack_rec should be my friends! Uuuhhh - the waveforms looks ugly
Yes - Dexed and others synths worked, so I thought that high CPU usage makes a problem. But I think you are right: There seems to be an “overload” of the plugin output!
What I am currently not really understand is why this happens. PiSound and Hifiberry may have a different chipsets or a different internal value(?) on which level the output amplifier is used? I thought this is normalized? That may cause this problem when using the same values on both plattforms.
On Zynthian/Hifiberry I have a problem with the mda-ePiano plugin (and this should also be a problem on PiSound - I will check this soon): Without gain-reduction-plugin on the output of the mda-ePiano you also get digital distortion. So the solution maybe to add a simple gain-reduction before connecting to the outputs.
I will do this the next days. And I will try the solution for fixing the distortion also… What I have learned: digital audio is not as easy as I thought
Hey, indeed the audio produced seems different. As jack_capture records the audio data before it is sent to the audio card, the issue is most likely in the software.
I’d suggest keep the test MIDI data simple, like a couple of single notes, so that the waveforms could be compared more easily between different cards / implementations.
Based on the single note patterns I produced in the screenshots in my previous post, I’d say the plugin may be miscalculating some buffer length with the configuration parameters present when pisound is the output device. Would it be possible to log the audio modes used and compare with the HiFiBerry DAC? I think some other parameter than the sampling rate (sample bits or format?) may be different too which doesn’t get accounted for appropriately, causing such audio issues to occur.
I created an update: mod-pisound-1.0.img.xz (downloadable until 31.5.2017). There is still the problem with setBfreak. I havn’t found why it works on Zynthian but not on my PiSound installation. I also added much more plugins and fixes.
Good day Holger,
I just received my pisound. Is there any way I could get a copy of the mod-pisound SD card image file posted back in May? I noticed its no longer hosted or available at the URL above. Although I’ve got a HiFiBerry, I’d like to play with this new hardware too.
I don’t know much about MODDEP… my test-image boots a MOD-UI and you can access it via “IP”:8888. I put lots of plugins onto this image.
PiSound works currently not with Zynthian because there are GPIO conflicts. With the new encoder board or my current implementation with controlling Zynthian via OSC the GPIOs will be free for using PiSound for Zynthian. So Zynthian may hopefully support (beside Hifiberry, AufioInjector, …) also PiSound as sound card.
Zynthian has different sound engines. One of the engines is MOD-UI (a “meta” engine). So Zynthian is not MODDEP or my MOD-GUI test image. It is a combination of hardware controlling, a screen and software behind - a full synth.