Live data from Hacker News

A low latency guitar effects processor suitable for running on a Raspberry Pi

github.com

111–120 of 147 posts

Re: A low latency guitar effects processor suitable for running on a Raspberry Pi

#111
post #21

Earlier quoted context omitted.

Nah, low latency audio is absolutely possible, but not necessarily using pulse audio. Using either Jack for the low latency stuff has been the advice for years, but with the advent of pipewire you can mix and match without too much difficulty. A quick skim didn't turn up what audio backend this project is using, but I'm using patchbox with modep on my Pi4 as a bass pedal board and it's pretty much flawless low latenc…

Sep 2 of the build instructions says it requires RtAudio.

what is the latency of a raspberry pi running this type of software? can't find figures anywhere

Re: A low latency guitar effects processor suitable for running on a Raspberry Pi

#112

As an amateur musician, three things stand out: 1. I'd have a hard time seeing that small screen onstage, and my big foot would likely mash the wrong effects button. Others might find it easier. 2. There are tons of good, cheap effects boxes out there, and easy to find used. I like Pi boxes, but this seems like a homebrew replication of what's on the market. 3. All good boxes are low-latency, in my experience. It's a…

What are they? Am I missing a joke here?

Regular guitar pedals are cheap and abundant.

Re: A low latency guitar effects processor suitable for running on a Raspberry Pi

#114

Earlier quoted context omitted.

Nah, low latency audio is absolutely possible, but not necessarily using pulse audio. Using either Jack for the low latency stuff has been the advice for years, but with the advent of pipewire you can mix and match without too much difficulty. A quick skim didn't turn up what audio backend this project is using, but I'm using patchbox with modep on my Pi4 as a bass pedal board and it's pretty much flawless low latenc…

Wow, what fx are you running -- and does that or could that include convoluted reverb? (Convoluted reverb is utterly awesome but more processor intensive than almost anything else) Edit: and sorry, to be helpful, by low latency, could you meantion how many ms that is -- because while I'm very happy for you, and really interested, 15ms is very different to say 5ms or lower

My normal chain is a noise gate, followed by a comp, a little emulated tube drive, an SVT amp model, an impulse response modeled cab simulator (of course running a 8x12 SVT cab), a plate reverb, and a limiter. I've got some crazier ones, but as a beginner bassist, that's all I really need. There are literally hundreds of effects to choose from though.

Convolution reverb is an option, but it ended up being a little more than the Pi4 could handle iirc. I didn't tinker with it much though.

Latency is under 10ms, I'd have to go back and check my settings to confirm exactly though.

Re: A low latency guitar effects processor suitable for running on a Raspberry Pi

#115

Earlier quoted context omitted.

Wow, what fx are you running -- and does that or could that include convoluted reverb? (Convoluted reverb is utterly awesome but more processor intensive than almost anything else) Edit: and sorry, to be helpful, by low latency, could you meantion how many ms that is -- because while I'm very happy for you, and really interested, 15ms is very different to say 5ms or lower

My normal chain is a noise gate, followed by a comp, a little emulated tube drive, an SVT amp model, an impulse response modeled cab simulator (of course running a 8x12 SVT cab), a plate reverb, and a limiter. I've got some crazier ones, but as a beginner bassist, that's all I really need. There are literally hundreds of effects to choose from though. Convolution reverb is an option, but it ended up being a little mo…

Just double checked my jack settings; I'm running my interface at 48000hz with a buffer size of 128 and 2 periods for a theoretical latency of 5.33ms. I'm sure USB adds a fraction of a millisecond as well.

Re: A low latency guitar effects processor suitable for running on a Raspberry Pi

#116
post #37

Earlier quoted context omitted.

I think the hip new guitar effects/sim is the Quad Cortex from Neural DSP. I've seen Kiko from Megadeth uses it for his live shows.

I think the AxeFx has more virtual knobs, but the QC is easier to use, and has Kemper-like sound capture tech.

The QC is my go to pedal these days. I have a Helix (rack) and a Kemper (rack). While there have been some hiccups on software it really is a solid little box.

Re: A low latency guitar effects processor suitable for running on a Raspberry Pi

#117
post #8

> Note that since the server program exposes an HTTP server you can actually navigate to the IP address of your PI from any device connected to the same wifi and control your pedal chain from there. That's a killer feature for me, hiding at the end of the README. I have a Fractal Audio FM3[0] at home, and the only way I edit my patches is using their editing software over a USB connection to the device. Adding the ab…

Always hear about the Fractal Axe FXIII--seems like the gold standard in guitar FX. Didn't realize they had smaller, non-rack-mount form factor devices. Very interested in trying out the FM3 now that you brought it to my attention. Thanks!!

AxeFX is absolutely insane in amount of control it gives you over your tone. I would say far too much control. Probably the best tool for a tone tinkerer.

Re: A low latency guitar effects processor suitable for running on a Raspberry Pi

#118

Sweet, was just looking for something like this the other day. My use-case is not for guitar, but just to offload some fx processing out of a DAW - a friend and I have gotten into jamming recently, and while you can do just about any musical production task these days with a budget laptop and enough patience, where you quickly run into limitations is running multiple realtime effects. I'm not yet serious enough about…

The 500% markup should also get you reliability and a decent chance that your tech is familiar with it were you ever to be on stage. Look around, everyone uses the same stuff, for the most part.

Re: A low latency guitar effects processor suitable for running on a Raspberry Pi

#119

As an amateur musician, three things stand out: 1. I'd have a hard time seeing that small screen onstage, and my big foot would likely mash the wrong effects button. Others might find it easier. 2. There are tons of good, cheap effects boxes out there, and easy to find used. I like Pi boxes, but this seems like a homebrew replication of what's on the market. 3. All good boxes are low-latency, in my experience. It's a…

> I'd have a hard time seeing that small screen onstage,

The project is using a 7" (17.7cm) LCD display. The Line6 HX Stomp is very popular and has a 2.4" (6cm) LCD display.

Re: A low latency guitar effects processor suitable for running on a Raspberry Pi

#120
post #7

Very cool, I've ordered a Raspberry Pi touchscreen this weekend and it should arrive today. I want to make a MIDI sequencer with it, or at least play with the idea. I hope my old Raspberry Pi can work with MIDI (over USB) without too much latency..

Depends on how you want to utilize it. If you want to connect it to a computer as a MIDI device, you'll have to use an Rpi4 or one of the Pi Zero's. The Pi's The RtMidi library is probably your best bet for getting started. I found the ALSA library to suit my workflow a bit better, but the setup is pretty obtuse. RtMidi is much more user friendly in that regard. Also, look into implementing the Ableton Link library.…

Ideally I'd sync it with Ableton's clock. I'm using Ableton only for tempo and multitrack recording. Maybe this is achievable without the RPi being a MIDI device? Sending messages over the network, like GuitarEffects which uses WebSockets. My RPi 2 doesn't support gadget mode (I should probably start looking for a RPi 4).

I'm currently using an Elektron Digitakt to sequence my analog gear - it's great - but unfortunately the DT is limited to 8 MIDI tracks with only 1 LFO per MIDI track to automate MIDI CC data. I'd love a Cirklon Sequentix but the waitlist is just too long (3 years atm, arghh).

I wonder if I can hook up something like a Midiface 16x16 (https://miditech.de/en/portfolio/midiface-16x16/) to the RPi. The Midiface is Class Compliant so maybe the RPi can use it natively..(?) I'm a bit worried about performance though.

Thanks for your suggestions, I'm going to look into them!

Post reply on HN