from Hacker News

I built a amp+cab+effects simulator for guitar on a Raspberry Pi 4B

by fivedogit on 4/19/20, 7:17 PM with 66 comments

  • by irscott on 4/20/20, 12:42 AM

    I want to say this looks like a great product. I was very surprised at how "complete" it seems. I manage one of the most iconic guitar stores in the world and have been selling gear and generally been a gear head for 15+ years. Needless to say I was extremely skeptical when I read the title of this article.

    If you can market this and produce it at scale I guarantee you'll sell millions of these things to the middle of the road guitar center learning to play guy. That demographic is fucking huge and probably represents 80% of the guitar based economy.

    I would market it that way. I would market this as an easy fuss free interface for conjuring classic tones to learn and play with your favorite artists. If possible a Rocksmith style learn along feature would be amazing.

    Really impressed with the simple interface, the apparent ease with which you dial up reasonably good jcm 800 and acoustic type sounds, and how the Alexa script seems to automatically dial in a tone to match the backing track.

    Really well done. If you get it to market hit me up I guarantee I can sell these things.

  • by zwp on 4/19/20, 8:36 PM

    Great article, I wish I'd seen the mid-project posting to HN. I was skeptical about the Alexa integration but that seems to work well.

    > ludicrously difficult to set up. Laptop + low-latency Linux + Ardour + QLC+...

    This resonates [sorry] with me. Linux sound today seems painfully reminiscent of Linux X-Windows 20 years ago. There's a lot of painful voodoo, competing control systems and legions of mostly out-dated forum threads of dead-ends, anecdotal advice, misinformation. I'm hoping that the next Ubuntu Studio will Just Work on the laptop that I have put aside for it and that I won't have to waste more time in the Pulse/Alsa/Jack soup.

    I was aware of Guitarix but have not yet played with it. My youngest is learning electric and we've got to the point where we can play together, with me pounding out the bass line on an old classical we had lying around(!). That is a blast but I wasn't really intending to become a bassist. If I were to pick up an electric guitar to fool around on, can Guitarix drop me down an octave and make me a pretend bass player? (I had a quick poke around the Guitarix wiki, couldn't see anything). There must be DAW processing plugins to do this, but I'd really like to be live. Are there other solutions? (apart from buying more instruments I mean...).

    Oh, and I love this:

    > So I bought a 3D printer and became a CAD guy, I guess

    "I had a hard problem to solve... so I... casually nuked it" :)

  • by utopcell on 4/20/20, 2:15 AM

    I have played with guitarix in the past, and having looked at some of its tube amp simulation code, I have great respect for the amount and quality of work that has gone into it. That said, in my opinion, its modeling capabilities are not on par with the main software sims out there.

    My portable solution is an Intel Compute Stick coupled with a Vox AmPlug I/O for 24-bit/48KHz input, powered by a 10Ah powerbank. I use Bias FX 2, but one could use Amplitube or Helix Native just as easily. I attach these to my strap and it is completely out of the way when I'm playing. The whole setup on the hardware side cost me <$130, and in return I get the best modeling software can provide. It is however a pain to control.

    Probably the "cleanest" portable solution would be the Boss Waza Air headphones. There are no wires at all!, and all modeling is done on the headphones themselves. At $400, they are on the expensive side though.

    If one wanted a small amp, it is probably hard to beat Positive Grid's Spark, which can now be had for ~$200 and is also voice-controlled (a gimmick if you ask me). An even cheaper solution would one of Laney's Mini or MiniStack amps, which hook up to an Android or an iPhone that runs ToneBridge. That's a lot of effects and modeling for ~$60.

  • by jkincaid on 4/19/20, 9:46 PM

    This is really interesting — thank you for building it. It seems some of the comments here are living up to HN's reputation. May that prove to be a good omen, as it has been in the past.

    The main thing I'm wondering is whether there's a way to record with this (so here's my wishlist). Often I'll be practicing along to another song, or just noodling around, and I'll really wish I had recorded what I just played. Would be amazing if I could say, "Alexa, record that", or "Alexa, record the last 90 seconds".

    Similarly: "Alexa, record this." (and then after X minutes if I forget to stop the recording / no input is detected Alexa asks if I still want to be recording).

    "Alexa play a metronome at 80 bpm and record this". "Alexa, play the last track and record a new track" (gotta make this very clear so as not to confuse overwriting the original vs recording additional layers). Sync the recording folder w/ Dropbox so it's ready for my DAW. Save two streams: one clean of the raw guitar (so I can tweak to my heart's delight later), one with the applied effects.

    I'm curious to dig into the tones more; a lot of apps are goodish but don't quite get it right. S-Gear is the best plugin I've found. Also, I'm a huge fan of the amPlug 2 line from Vox. $40 for really impressive tones via a battery powered gadget as big as a few matchboxes. Sounds great hooked up to speakers and good enough to use in recording. But they don't give you a lot of options in terms of effects.

    Great project! Hope the above is useful — I'll be following along!

  • by m0zg on 4/19/20, 9:02 PM

    For comparison, here's what the current very best in this field looks like: https://www.fractalaudio.com/iii/

    $2K (and an absolute steal at this price), high end DSPs, high end multichannel ADCs/DACs. Thankfully, lots of knobs and buttons, and no Alexa of any kind. Sounds amazing. I have one.

  • by kbr2000 on 4/20/20, 7:38 AM

    Cool project, well done!

    Reminded me also of the Jesusonic [0] FX processor, by Justin Frankel [1] of Winamp, SHOUTcast, REAPER, ...

    [0] https://www.cockos.com/jsfx/

    [1] https://1014.org/

  • by sbr464 on 4/19/20, 8:39 PM

    Check out Bela also for low latency audio.

    https://bela.io/

  • by zachrose on 4/19/20, 9:08 PM

    I wonder if it would be possible to build a six-item menu selector that worked by picking up when you tap a string. This would get in the way of alternating between selecting an amp and trying that amp, but maybe there's some way to detect when a string has been tapped from behind the bridge?

  • by Gravityloss on 4/20/20, 9:52 AM

    Guitarists like to control their things with their feet so their hands and mouth stay free. There is a wide array of midi controllers available in pedal form. Tap with your foot, double tap, hold, scroll with multiple taps etc. Many artists use them to do the control plane of their effects routing, so they are rugged and battle tested. Here are some: https://customboards.fi/collections/midi-switching

  • by weej on 4/19/20, 9:28 PM

    Thanks for sharing. This is great. I appreciate the additional insight in the comments on the software behind it for the guitar effects & tones. Kudos on the experimentation and iterations to meet your needs. Wish I would have seen this for a potential DIY project before I went in on purchasing the SPARK amp for at home practices and FXs.

  • by pm on 4/20/20, 2:41 AM

    I've seen the Spark ads popping up in social media for the last couple of weeks, and while it's not really my thing in terms of guitar playing (I prefer restricting my pedalboard), I can appreciate the effort going into a product like this, especially as a software engineer.

    How much work have you put into this so far?

  • by yummypaint on 4/19/20, 9:01 PM

    People interested in trying out this kind of thing should also check out vcvrack. Its a free fully featured modular synthesizer system, also very easy to set up. It should be possible to run it on a pi, though i havent tried that personally. It also has excelent midi integration, so one could try to reproduce some of the hands free control with a program that does voice recognition and supports a virtual midi interface.

  • by thdrdt on 4/20/20, 5:35 AM

    For those who like this: it also reminds me of a small company that makes Hooks amps.

    The Wizard also include those simulators but the nice thing is it uses analog knobs. But you can program presets and the knobs will move back to the preset settings.

    http://www.hookamps.com/phone/wizard.html

  • by ricardobeat on 4/19/20, 8:27 PM

    Awesome project! I was really hoping to read about the amp/cab simulator and effects running on the Rasperry Pi as the title mentions, but the software side is entirely missing from the story.

    Note that from a cursory look at the links, there hasn't been updates since 2018, and the KS project never launched.

  • by ChrisAntaki on 4/20/20, 6:27 AM

    Thanks for building this! Also, great performance of Still Remains. I'm looking forward to checking out the Kickstarter. Any chance you could add support for Google Assistant?

  • by StavrosK on 4/19/20, 8:14 PM

    This looks impressive, but I'm most curious about the Alexa integration. How do you do that without having to say "ask <app name> to <x>" every time?