I'm guessing the harder part would be actually finding a Pi for this?
A low latency guitar effects processor suitable for running on a Raspberry Pi
61–70 of 147 posts
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#62Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#63Earlier 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.
RtAudio is just an API wrapper which calls JACK, Alsa, etc behind the scenes and does not add latency, just the overhead of a couple c++ method calls
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#64There is also Pisound for low-latency guitar effect processor which is a hat for the Raspberry Pi. https://blokas.io/pisound/
The UI, MODEP, is based on the Mod Devices work on their open source pedal (Originally Mod Duo) > https://mod.audio/.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#65Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#66There is also Pisound for low-latency guitar effect processor which is a hat for the Raspberry Pi. https://blokas.io/pisound/ The UI, MODEP, is based on the Mod Devices work on their open source pedal (Originally Mod Duo) > https://mod.audio/ .
I bought a PiSound to tinker with the Midi interface a bit, had no idea it was this powerful.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#67From 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 single use applications in guided artillery shells.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#68Also see: https://rerdavies.github.io/pipedal/
which solves the problem with using a bar's Wi-Fi by using Wi-Fi Direct.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#69I'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 definitely enough bandwidth here to do what you need to per unit time.
Re: A low latency guitar effects processor suitable for running on a Raspberry Pi
#70From 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…
According to Analog's product page [1] for the ADSP-21469, it delivers 2.7 GFLOPS at 450 MHz.
And Wikipedia's page of all the RPi models says that the latest (4B) manages 8 GFLOPS at around 1.8 GHz.
If that means that the answer to your question is "yes" or "no" is unfortunately a lot harder to Google and/or figure out. I would assume that the SHARC-based devices run on the metal, whereas most applications for the Raspberry Pi run under Linux, for instance.
[1]: https://www.analog.com/en/products/adsp-21469.html#product-o...
[2]: https://en.wikipedia.org/wiki/Raspberry_Pi#Simplified_Model_...
Edit: grammarish.