Nice project, but nonway on earth I am taking anything with a breadboard and jumperwires onto stage — except maybe if I plan to make it part of the performance
A low latency guitar effects processor suitable for running on a Raspberry Pi
71–80 of 147 posts
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#72From my understanding the Line 6 Helix uses two 450MHz SHARC processors, ADSP-21469. Other effect/amp modelers use more or newer of the same family[0]. Can anyone comment about the relative processing power of a RPi vs the market solutions? Is the RPi theoretically good enough that a pedalboard could be completely modelled? [0] Interestingly, it sounds like SHARC chips were designed to be low cost processors for sing…
Generally this type of work is done on DSPs and FPGAs, because they can generally get much lower latency than a CPU. While this can get latency low enough that nobody will notice, it is still there, and there isn't room for anything else in your signal chain to also have latency and still be unnoticed.
They will still have a CPU on devices like this, but all it does is run the UI, the sound processing is not done on a CPU.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#73I'm still patiently waiting for future digital mixing consoles to do all processing in software on inexpensive x86 or ARM processors. Currently due to latency and reliability requirements all DSP work is done on dedicated chips or FPGA which brings up the BOM and engineering cost. They often have a small ARM/Linux module which is used for the displays and network control. The CPU tech is here today, and modern genera…
Modern CPUs are surprisingly good at low-latency video as well. SIMD on something like a Zen4 core is a really big deal if used properly. I've got some prototypes in C# that can draw a 1080p bitmap and encode to JPEG in under 10ms. Using single threading, socket mux servers and aggressive multimedia timers means my network delay is usually right at 1ms. I feel like if you are just worried about audio, there is defini…
While video needs more CPU power, it can tolerate higher latency than sound.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#74I thought is hard to have low latency audio in Linux with stuff like PulseAudio.
Possible with jackd etc I switched to BSD and got much better latency on the same hardware But I think that was the alsa -> BSD oss driver swap, which is possible on linux too. I had just never tried it, since I assumed linux was best (I'm only sharing this cus i think its interesting, and may help you get good latency)
I've begun tinkering with GhostBSD lately just to learn more about BSD. Pleasantly surprised to find a lot of familiar linux audio tools were ported or can be easily made to work. Also happy that my ancient Presonus AudioboxUSB works fine in BSD. So much so that I get less random audio glitches than I do under windows 10.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#75While 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.
Norns is made and supported by Monome, and it is very much supposed to be a Product That You Can Buy... except unfortunately it's based on the Compute Module 3, which has been unavailable for a good while. They have been available in small batches occasionally over the last year, and hopefully will be more available soon.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#76While 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.
Surface mount soldering is not too hard. I can't view the BoM on mobile, but from the photos the soldering looks achievable for someone with experience soldering through hole. Take a look at the document here https://github.com/monome/norns-shield/tree/main/bom - if it's mostly 0805 sized components you should be fine. Even a few 0603 would be okay if you have good vision and a steady hand.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#77Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#78Earlier quoted context omitted.
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!!
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.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#79This is awesome. I'd be really interested to find out if a Raspberry Pi can run an open source amp modeler like NAM ( https://github.com/sdatkinson/neural-amp-modeler ).
I'm not sure if the GPU is powerful enough on the RPi, maybe something like a Jetson Nano could handle running ML models better.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#80> A Low Latency Guitar Effects Processor What's the latency? I can't find numbers anywhere.
IME, if you can't find an important quantity like that front¢er in an advertisement, then its value is going to be terrible.
Applies to many things related to an advertised product. Things like price, quantity, material, country of origin, standards met, certifications, scores, etc.