A better alternative to the Raspberry Pi which is more suited for musical applications (and currently much cheaper) is the Daisy Seed by Electro-Smith[0]. You can program it in C++ / Pure Data / Arduino and Max/MSP Gen~. The community is very helpful and there are plenty of examples to start with. They also provide a few options to get started with some knobs/buttons. I'm not affiliated with them, just admire the whole ecosystem.
A low latency guitar effects processor suitable for running on a Raspberry Pi
121–130 of 147 posts
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#122Earlier quoted context omitted.
none, of course
Lol ok. Meanwhile the rest of the industry is moving on. I mean, how do you even do an wired connection to a drone? A lot of times guitarists will perform on a stage and the clients wants aerial views without the cost of a crane. Do you just tell them you can't do it and have them go with a different company?
I'm a little confused by this thread - it seems like you suggest that the drone should be controlled by the SBC in an effects pedal, that the guitarist is using to provide low-latency audio processing? As a techie and perpetual-intermediate musician, that seems a bit odd...
But, incidentally, at my day job I'm working on an embedded Linux system where audio latency matters, and which may well wind up with a WiFi radio (where latency probably doesn't matter so much). So, I'd like to understand issues in this space.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#123Earlier quoted context omitted.
The Mod Dwarf (and its predecessors) also allows web control and it supports standard LV2 plugins :) https://mod.audio/dwarf/ https://wiki.mod.audio/wiki/LV2
The first site is remarkably brief about its actual capabilities. Is there somewhere with more information about it?
Simplifying a bit: It's a pedalboard with a Linux SBC inside where you can load LV2 plugins and chain and route them as you wish. It has a sleek web interface for management and some short of "pedal store". Like an advanced multieffects pedalboard. Originally the MOD devices where crowdfounded.
There's a small introduction video: https://www.youtube.com/watch?v=5USQ7BsZ054
And Modep (as @tcrenshaw wrote in another comment) this is a MOD emulator for Raspberry pi, just in case you want to play with it: https://blokas.io/modep/
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#124While not a guitar effects box another project that does low latency audio things with an RPI at it’s core: https://monome.org/docs/norns/ Open source version: https://monome.org/docs/norns/shield/
This is a neat little box, but pre-soldered ones seem to be only available on the used market. There are bare PCBs out there, but I’m not very confident with SMD parts. This is the thing that bums me out with DIY audio: people come up with extraordinary designs, do a limited run and then never (or rarely) make any more.
> people come up with extraordinary designs, do a limited run and then never (or rarely) make any more
I never bought a milkymist. There are no more being produced. The design has never been updated for modern formats, such as hdmi. I have no clue how to design hardware.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#125Earlier quoted context omitted.
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.
Thanks! Musically that's really viable and fun setup
A really helpful data point :)
--
You're doing great! You don't need my help, but just share my own path, because it's fun :)
Yeah, play the bass, if i start talking about computing im not helping...
Err, why am i still here?
I switched to BSD or the OSS driver and went from massive effort ~5ms to zero effort ~2ms
Then I made a two button controller and pedal->usb, and started programming an arbitrary effects controller: a looper + buttons to switch the pedal to control any fx parameter
Fun, but it didn't help me make better music :)
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#126What is he using for actual audio interface? RPi has something awful onboard and none of the pictures show anything external. USB would add 0.25ms latency just for being USB, best case.
Round trip latency for Raspbery Pi 4 USB audio measured using a guitar gable from output to input: https://rerdavies.github.io/pipedal/AudioLatency.html
Stable audio at 3.9ms latency (measured using a loopback cable).
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#127Earlier quoted context omitted.
Don't go leaving it exposed if you connect it up to the venue's WiFi, if you're playing live. ;)
Don't run wifi and real-time software at the same time.
The Raspberry Pi 4 has separate USB hubs: one for WiFi and ethernet (an internal hub), and another for external USB ports. The USB port service loop will run with higher priority, so there doesn't seem to be any serious adverse affect.
The same isn't true for SD card access, which does cause dropouts. I've seen a video that suggests that disabling power management for the SD card hardware will correct the problem -- specifically that changing power state causes a 3ms delay. But I'm not quite sure how to go about disabling that on a Raspberry Pi OS.
. WiFi doesn't seem to affect audio latency. That's not true for Raspberry Pi 3, where WiFi and USB ports do run on the same USB hub.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#128While not a guitar effects box another project that does low latency audio things with an RPI at it’s core: https://monome.org/docs/norns/ Open source version: https://monome.org/docs/norns/shield/
This is a neat little box, but pre-soldered ones seem to be only available on the used market. There are bare PCBs out there, but I’m not very confident with SMD parts. This is the thing that bums me out with DIY audio: people come up with extraordinary designs, do a limited run and then never (or rarely) make any more.
A big part of the problem is FCC certification.
If you ship parts, you can avoid it. If you ship it assembled, you'll need to spend tens of thousands of dollars getting it FCC certified.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#129As others have mentioned, I think the interesting thing here would be understanding the latency for processing the signal. Anything in the single digit milliseconds would be fantastic! I know at one point I was looking into Raspberry Pi and ended up on Pedal Pi[0], though I couldn't get the parts I needed to make it work. I ended up using Teensy[1] and related audio shields[2] to get things working from a sound/accep…
Stable USB audio with 3.9ms latency is possible (measured using a loopback cable). Not sure if this product manages to achieve that or not.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#130A better alternative to the Raspberry Pi which is more suited for musical applications (and currently much cheaper) is the Daisy Seed by Electro-Smith[0]. You can program it in C++ / Pure Data / Arduino and Max/MSP Gen~. The community is very helpful and there are plenty of examples to start with. They also provide a few options to get started with some knobs/buttons. I'm not affiliated with them, just admire the who…
But Pi4 gives you about 400% better CPU performance. And you'll need it for a serious effect chain.