Boss GP-10 guitar as MIDI controller

Using Zynthian
1

Hi guys

Sorry if I’m asking in the wrong place but, here goes.

I have a boss GP-10 and a gk pickup on my guitar.

I’m also a raspberry pi fan and wondered if anyone could help with this.

I would like to plug my GP-10 into a raspberry pi running zynthian and use my guitar as a midi controller for the zynthian synths?

Thanks

2

I’ve never tapped into it, but I think Zynthian includes an experimental audio-to-MIDI converter.

3

I don’t own a GP10, but the specs say it outputs midi over USB. The Zynthian supports USB midi using the RPI USB ports. I use an Arturia MINILAB keyboard with Zynthian. It only outputs midi over USB as it doesn’t have standard MIDI ports, but it seems to work okay for me. I suspect the GP10 would work okay as well. @Vincent has posted he uses a GP10 in his setup, so perhaps he will reply to let you know if he has used it to trigger his Zynthian.

4

Oh I didn’t know that. Definitely worth a try

Ta

5

Thanks for that. I will have to did a little deeper on this one. Could be really interesting.

Thanks

6

Sound On Sound review says, “…the GP–10 USB output is not MIDI class–compliant…” and others have said it doesn’t work on Linux so I suspect it won’t work but it is quite easy to test: plug it in and see if it works. Shame that it isn’t class compliant hence requires proprietary drivers.

7

Yet others have said it does!

1 Like
8

I can’t speak for GP-10 precisely, but there’s a lot of USB hardware that is technically class compliant but lies about it in their hardware descriptors, and appearing to require proprietary drivers because of this (yes, mind boggles). Linux supports a many such devices via a “quirks” mechanism where basically the broken vendor descriptors are overridden to appear as class-compliant and voila, it just works.

9

The GP-10 MIDI probably is class compliant (I don’t have mine to hand so I can’t check) but I suspect what isn’t class-compliant is the multitrack USB audio, so it does need drivers to be fully functional.

Most Roland hardware recently has some form of audio over USB - AIRA, TR8 and GP-10 are examples I’ve actually owned/used.

10

As far as I can tell the GP10 doesn’t allow Midi bridging directly out of the unit.
It is possible though to trigger external midi by using a USB MIDI host such as the MIDX10.

11

Hi thanks all

This has been really helpful and I have pushed Linux to get where I want to be.

But I have had to admit defeat and reluctantly defaulted back to windows as the host. I can trigger all my midi equipment through that and it works well with little latency, bar the limitations of physics :wink:

Thanks again all. I’m going to get back to playing Now

Ta

12

I also have a GP-10, and it has a recent improved kernel driver that splits out the six strings into six channels, with two more that I think is the processed output of the pedal. Needless to say, this has possibilities.

The zynth appears to be seeing the device, but this is interesting - it sees an 8-channel device in aplay -l, but it thinks it’s the headphones. Is this normal because of the kludge to use the pi audio at the same time?

root@zynthian://zynthian# lsusb
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 0582:0185 Roland Corp.
Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
root@zynthian://zynthian# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Headphones [bcm2835 Headphones], device 0: bcm2835 Headphones [bcm2835 Headphones]
Subdevices: 7/8
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
Subdevice #4: subdevice #4
Subdevice #5: subdevice #5
Subdevice #6: subdevice #6
Subdevice #7: subdevice #7
card 1: GP10 [GP-10], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 2: vc4hdmi0 [vc4-hdmi-0], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 3: vc4hdmi1 [vc4-hdmi-1], device 0: MAI PCM i2s-hifi-0 [MAI PCM i2s-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
root@zynthian://zynthian#

13

Update: based on examining qjackctl on my desktop, I made the following modification to the options for Generic USB Device (I’m pretty sure all I changed was the hw: entry but it was last night so not positive):

-P 70 -t 2000 -s -d alsa -d hw:GP10 -r 48000 -p 256 -n 2 -X raw

For any other curious GP-10 owners out there, whatever weird outputs the aplay might put out, it appears that I have eight channels of audio available in my zynthian - as I said, a good driver got added to the kernel not too far back. I have not yet verified that six of them correspond to the six strings, but I’m pretty sure that channel 1-2 were the processed output of the pedal, and when I turned those channels off the signal sounded more or less clean, I think.

Am definitely curious about that alsa output though.

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