Get the top HN stories in your inbox every day.
sklarsa
mr_sturd
Don't go leaving it exposed if you connect it up to the venue's WiFi, if you're playing live. ;)
giantg2
Audience participation show.
Our_Benefactors
I had sketched an idea for a web ui that would talk to a VCV instance, outputting signals to a real eurorack device with an expert sleepers module… need to keep hacking on that.
867-5309
DefCon Big Band
worik
Don't run wifi and real-time software at the same time.
mattkrause
Using wifi to trigger real-time software is often a bad idea, but using it to configure responses to future triggers isn’t necessarily so bad.
rerdavies
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.
mr_sturd
The only signals going over WiFi here would be controls for the virtual pedals.
zamnos
What wireless technology would you recommend instead then?
darkwraithcov
The core audio driver does a pretty good job with this.
undefined
nightowl_games
Somebody should make a device that plugs into a fractal axe FX and hijacks the USB connection and exposes a web interface. Now that'd be cool!
zamnos
There are a bunch of USB over IP boxes you can buy, so it depends on the m what you're looking for, port-wise. That plus a wifi router gets you what you're looking for.
Eg https://www.digi.com/products/networking/infrastructure-mana...
obituary_latte
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!!
tecleandor
The Mod Dwarf (and its predecessors) also allows web control and it supports standard LV2 plugins :)
Blackthorn
The first site is remarkably brief about its actual capabilities. Is there somewhere with more information about it?
vondur
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.
bjelkeman-again
I think the AxeFx has more virtual knobs, but the QC is easier to use, and has Kemper-like sound capture tech.
theflyinghorse
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.
metmac
While 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/
rotexo
Also Pisound (https://blokas.io/pisound/) which has the benefit of built-in din MIDI, but without the active community sharing software (you kind of have to build everything yourself with PD or SuperCollider). Some people have gotten Norns running on pisound, but I could never get it to work.
worik
I do not know about Noms, but I have a Pisound
It has audio in so needs no external usb sound hardware.
It also has a programmable button. A simple idea but very useful
jnovek
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.
rvense
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.
dhon_
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.
grepfru_it
> 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.
rerdavies
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.
ghostly_s
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 it to start spending $ on effects pedals (which typically cost hundred of $ each), or even to have a clear enough idea of what pedals I would want, but I know enough about electronics to realize most modern ones are just a glorified arduino with a a 500% markup, so a budget-friendly programmable swiss ay knife pedal would be a dream.
For my use-case the touchscreen is entirely unnecessary (programming it via a WebUI sounds more convenient anyway if you don't need to use it sans PC), which is inflating t he BOM by about 500%, and of course RPi4 is a uniquely poor choice of target platform at this particular moment in time, so seeing if it can run on a headless Pi Zero is definitely going on my endless to-do list. ;)
nick__m
I use an ESP32-A1S board for that. I use this project https://github.com/pschatzmann/arduino-audio-tools/ and the platformIO vscode plugins.
Have a look at this example to see how easy using that library is : https://github.com/pschatzmann/arduino-audio-tools/blob/main...
km3r
I was thinking about something similar but wondering if you could do it over Ethernet and the VST API with low enough latency to be useful for a DAW. Or if you can figure out a way to make latency less of an issue all together and enable remote VSTs.
regpertom
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.
jamesgill
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 fundamental thing I think most players need.
thealienthing
You’re definitely right. I think the draw of all of this is to make it yourself. The same could be said of people who make their own diy home weather stations or web servers. You could always outsource for the same thing that’s better, more frequently updated and probably cheaper when you factor in the time it takes to make. It’s just neat to make the tools that you ordinarily have to dish out catch to get. :)
tasty_freeze
> 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.
Min0taur
I agree with both of these observations.
AlecSchueler
What are they? Am I missing a joke here?
speed_spread
Regular guitar pedals are cheap and abundant.
AlecSchueler
Comment was edited after my comment to include the things that stand out, which were previously missing.
razerbeans
As 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/acceptable delay perspective. But being able to get things going on a Pi would probably make more of the advanced input controls much simpler to implement simply from a OS support perspective (like in this project with the WebUI). The UI I'm seeing in this project looks great and it would be cool to potentially see something like kits/preinstalled images roll out for this!
[0] - https://www.electrosmash.com/pedal-pi [1] - https://www.pjrc.com/teensy/ [2] - http://blackaddr.com/products/
rerdavies
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.
chestervonwinch
Also, the teensy audio library is great!
snarfy
> A Low Latency Guitar Effects Processor
What's the latency? I can't find numbers anywhere.
worik
Exactly
What is the expected latency of those cheap usb devices?
I had one that was unusable live. Noticeable latency. Have they gotten better?
djbusby
IME it MUST be under 10ms
LgWoodenBadger
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.
digitallyfree
I'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 general purpose processors do a good job of handling low-latency audio. Someone just needs to put all that together in a unified and stable package...
huehehue
Not exactly what you're describing, but I've been running my band directly into Logic Pro on an M1 (both for recording, and live shows). Dry signals go through amp sims and effects processors, and then route to both a FOH mix and an in-ear mix all on the laptop.
Wish I had seen the OP's project months ago, but one bonus of the setup I describe is the ability to swap effects after the fact (by virtue of having the dry signal) and the ability to automate effects (so I can engage distortion etc as soon as we hit measure XYZ instead of having to click a pedal)
digitallyfree
I've done live mixing with a laptop, DAW, and interface in the past and it does work but it's not something I would be comfortable with for an important show. Even with something like SAC (which is specifically designed for the task) the chance of hangs, crashes, etc. go up as at the end of the day it's just a program running on top of your OS. The setup and config also gets a bit hacky and you'll be the only one able to use it. As far as I know the only specialized system that does this is the Waves LV1 which has a dedicated OS running on top of x86 hardware for processing. While I haven't tried it apparently it works quite well.
However I was more thinking of mixers like the QSC Touchmix/X32/etc. where the DSP probably eats up quite a bit of the unit cost, and how the price could be significantly brought down if the innards merely contained analog I/O and converters all tying into a powerful SoC.
kimburgess
It's interesting you mentioned QSC. They're one of the few vendors in the installed audio space that have made the jump to COTS hardware: https://www.qsc.com/resource-files/productresources/dn/dsp_c....
bob1029
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.
bluGill
While video needs more CPU power, it can tolerate higher latency than sound.
kimburgess
Spot on. For context: 60fps gives you ~17ms of wiggle room before you start dropping/delaying frames. With 96kHz audio you have 0.01ms between samples. Drift above 0.05ms and you'll start introducing time domain issues in the human hearing range.
In other words, 'realtime' audio processing needs to happen 1700x faster that 'realtime' image work. Bandwidth isn't limiting factor, deterministic and uniform latency is that challenge for any signal as the sample rate goes up.
bob1029
Fair point. Audio also has a tendency to require more serialized throughput in complex signal chains. Video is more trivial to chunk out and process in parallel.
PaulDavisThe1st
> I'm still patiently waiting for future digital mixing consoles to do all processing in software on inexpensive x86 or ARM processors.
Harrison Consoles have done this for more than 10 years.
I cannot confirm this in the same way, but I think it also likely that both Lawo and Studer digital consoles do this, and also possibly Allen & Heath. All 4 companies run Linux internally on their consoles.
TylerE
Modern CPUs are great if your watt (and thus thermal) profile is unlimited.
Not so great when they aren't.
londons_explore
Most processing of audio isn't CPU performance limited... For most realtime audio mixing, it doesn't matter if you use 1 watt or 10 watts for your CPU - the big speakers will easily be drawing far more, and the performers time will be costing far more than the electric bill anyway.
PaulDavisThe1st
> Most processing of audio isn't CPU performance limited
Processing, mostly true (though there are still some reverbs that can chew an awful lot of cycles).
Synthesis, however, is a different story. That is definitely CPU performance limited once you get into substantial numbers of voices/tracks/synths.
TylerE
It's CPU limited in the sense that it's extraordinarily latency/jitter sensitive.
digitallyfree
Modern consoles are plugged into the wall and are large enough for active cooling. For a 1U rack unit they can be cooled with small server fans; noise is not an issue as the amp fans are just as loud and the music will drown them all out anyways.
strangetortoise
Does this form a problem for digital mixing consoles? As far as I know, these already have fairly beefy fans for heat exhaust, so I don't know if they couldn't just add more airflow?
TylerE
Not especially. I'm more thinking of things that have a potential of being near a live mic, where a cooling fan is a no go, at least without a defeat switch.
iamsaitam
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.
rerdavies
But Pi4 gives you about 400% better CPU performance. And you'll need it for a serious effect chain.
honkycat
I've had some amazing ( horrible ) adventures in low latency music stuff lately. It has made me think about going back to the hardware side of music production. Previously I was an ableton-only dude.
All of the vst plugins are CPU bound and even though i have a top of the line i7 and 32 gigs of ram, my computer slows to a crawl when editing even moderate sized songs.
Specifically, there is an nvidia bug that introduces latency to real time audio, making guitar and other live performance unplayable.
It really sucks! At least it has finally been ack'd (Increase in DPC latency observed in Latencymon [3952556]): https://us.download.nvidia.com/Windows/531.18/531.18-win11-w...
This has been a problem for YEARS. Hopefully they will finally fix it.
jzombie
I don't know how this compares to your i7, but I dabble around using Pro Tools w/ about 15 or 20 tracks at a time with several effects running in unison, on an M1 Pro processor w/ only 16 gigs RAM, and I typically stay under 20% usage according to Activity Monitor.
I mostly play guitar and don't notice the latency in most effect chains that I use.
honkycat
Yeah it should perform way better than it does currently. There is a driver bug for Nvidia cards that causes it to run slowly and poorly.
It is extremely frustrating.
kbr2000
Well done!
For those interested: a predecessor called the "Jesusonic" was once made by Justin Frankel (of Winamp and REAPER fame): https://www.cockos.com/jsfx/ https://wiki.cockos.com/wiki/index.php/Jesusonic_Documentati...
:)
woudsma
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..
H1Supreme
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 < 4 can't go into "gadget mode". I bought a new v4 for this exact reason.
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. It runs over your network, and is honestly astounding how well it sync's devices.
woudsma
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!
riceart
Can you readily get an rpi4 anywhere?
The Odroid C4 you can actually get is an alternative with 4 USB ports and an OTG that is gadget capable. Unlike older models, mainline Linux support is decent.
thealienthing
I’d say you can most definitely do that. You can get usb midi conversion cables for next to nothing and send an out signal to a midi hub or Daisy chain it. Midi is a seriously slow protocol so as long as the actual audio processing is happening on other devices and you’re just sending midi to them, you’re definitely good to go.
mr_sturd
I've seen it done with the Pico, where it acts as a midi device when plugged in to a host machine; not so sure about the main boards.
zamnos
The pi zero hardware supports gadget mode and from there it's a bit more work to get it to enumerate as a midi device. The pi 4 supports this via the usb-c port.
https://raspberrypi.stackexchange.com/questions/71613/how-to...
silveira
Any samples or videos of this working? I would like to have a feeling of the latency and how the effects sound.
tecleandor
There's a two years old small video on reddit...
https://www.reddit.com/r/raspberry_pi/comments/p0jkb3/guitar...
Get the top HN stories in your inbox every day.
> 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 ability to program (and even control) my patches live over any wifi-enabled device is even cooler!
[0] - https://www.fractalaudio.com/fm3/