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Neural networks emulate any guitar pedal for $120

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Re: Neural networks emulate any guitar pedal for $120

#61
post #42

Can any skeptics weigh in? To me, this kind of tech is centuries away from fooling tone hounds.

Not much need to (or benefit in doing so). If you're somebody like AnalogMan, building pedals with careful selection of NOS transistors wired point-to-point, this is so utterly not a threat to you.

I've seen entirely analog circuits designed and built with the PCB parts and techniques used in these devices, that are miles away from the quality of good pedals, without even being digital or modeling at all. I'm sure the problem circuits measure completely fine, and then you A/B them with a truly great pedal and it's chalk and cheese.

If you try to argue the point, people committed to the digital modeling model get quite fierce, so tone hounds learn to just roll their eyes and not engage. You can also think of it as learning to rely on secret weapons.

Re: Neural networks emulate any guitar pedal for $120

#62

…at MP3 quality. This is fine if you like that sort of thing. I would note that latency is very important here: it's not going to be nice to play through if it's incurring any significant latency.

Just switch the Pi for a FPGA and the problem should be fixed.

That's not necessary. And FPGA doesn't have lower latency (I mean on the ms scale) compared to a Pi because of hardware. It has lower latency because it doesn't run a non-realtime OS.

You can just use a Pi with bare metal code or a real time OS.

Re: Neural networks emulate any guitar pedal for $120

#63

…at MP3 quality. This is fine if you like that sort of thing. I would note that latency is very important here: it's not going to be nice to play through if it's incurring any significant latency.

Yes, latency is huge. Modern digital audio stacks in consumer OSes are still completely terrible at this. Not that it's an easy problem to solve. But it's pretty hard to beat elections flowing through an analog circuit, when in the digital side you have to: convert analog to digital, run through the kernel to get to user space, run the bits through the RNN, send back to kernel space, convert to analog and finally sen…

The time in the RNN might be the only thing that's hard. We can commonly do A/D, D/A pretty quick. I can make a db request over a network, have it parse the SQL, execute it reading a bunch of SSD pages and return the sorted results in about 1ms.

The answer would probably be to reduce the 'learned' output to be a convolution kernel that gets run rather than the RNN itself on the input. Then the kernel only has to change gradually to produce a different sound not continuous processing to produce a particular sound.

Re: Neural networks emulate any guitar pedal for $120

#65
It is my understanding that capture based emulation of a given sound seems like a better idea than it really is. Say you capture a given amp or pedal sound - even if you get the latency down to acceptable #s, what if you want/need to turn a knob? Tweaking knobs is an essential part of the process of dialing in a sound relative to your guitar and output environment.

Contrast with the Fractalaudio approach of modeling each component of a device. Fractal's AxeFx is the gold standard and any geek would gush over the HW and SW engineering. The best part is that the company owner keeps improving his algos and pushing out updates for free. This device costs the equivalent of a good amp head and is loaded with more amps and effects than any of the competition.

Sorry if this sounded like an ad, but I am always surprised how little airtime this amazing product gets in hacker circles.

Re: Neural networks emulate any guitar pedal for $120

#66

It is my understanding that capture based emulation of a given sound seems like a better idea than it really is. Say you capture a given amp or pedal sound - even if you get the latency down to acceptable #s, what if you want/need to turn a knob? Tweaking knobs is an essential part of the process of dialing in a sound relative to your guitar and output environment. Contrast with the Fractalaudio approach of modeling…

The knobs can be included in the emulation. So that is to say, you model the unit as something having an audio input, and several controllers, such as knobs or switches. You then capture the behavior for all combinations of controller values, as part of the model. ("All combinations", for a potentiometer, might mean stepping it from 0 to 11 in increments of 1.)

The emulation ased on the model runs on a piece of hardware which has some generic controllers on it: some rotary encoders, a couple of switches and whatnot. These get assigned to the parameters of the model.

You could have a MIDI input on it, and use MIDI controllers, which would be cool. There are MIDI foot controllers that you can tilt with your foot to vary a parameter.

The different models could be assigned to MIDI program numbers. You could change the patch number with the foot controller, and vary the parameters with it also.

The foot controller might have, say, only two pedals, so you have to assign which ones you want: if the patch has five parameters, you have to fix the values of three of them and map the two important ones to the foot pedals you have. For the others, you can bend down and tweak the knobs on the unit itself.

Re: Neural networks emulate any guitar pedal for $120

#67

The video won’t play for me, but does this allow tweaking of parameters? The problem with most projects like this one is that it replicates the sound of a certain pedal with certain settings. That’s a major problem for most guitarists as playing with the knobs live is a big part of the attraction to pedals.

I designed and built a eurorack module around a pi zero with a usb audio input/output, voltage divider, op amp, and some pots connected to adc. Using rtaudio the latency was pretty low and gave me control of the parameters I wanted.

Given that this was the only really active process on the pi, it ended up working really well. I simply converted modules I had written for vcv rack.

I also built one that enabled usb host mode and acted as an audio device that worked with any daw. Ended up being pretty cool for about $20 of parts.

While not as cool as an ml system, given that I was already writing dsp, it ended up being pretty neat.

Re: Neural networks emulate any guitar pedal for $120

#68

It is my understanding that capture based emulation of a given sound seems like a better idea than it really is. Say you capture a given amp or pedal sound - even if you get the latency down to acceptable #s, what if you want/need to turn a knob? Tweaking knobs is an essential part of the process of dialing in a sound relative to your guitar and output environment. Contrast with the Fractalaudio approach of modeling…

the problem with this approach is you need to have knowledge about the circuit to make it happen, not only that, but you also need people, who can reconstruct the circuit digitally

this approach is not scalable (that's why the high cost)

the ML approach doesn't require any knowledge about the system (black-box) to produce the result

Re: Neural networks emulate any guitar pedal for $120

#69
post #68

It is my understanding that capture based emulation of a given sound seems like a better idea than it really is. Say you capture a given amp or pedal sound - even if you get the latency down to acceptable #s, what if you want/need to turn a knob? Tweaking knobs is an essential part of the process of dialing in a sound relative to your guitar and output environment. Contrast with the Fractalaudio approach of modeling…

the problem with this approach is you need to have knowledge about the circuit to make it happen, not only that, but you also need people, who can reconstruct the circuit digitally this approach is not scalable (that's why the high cost) the ML approach doesn't require any knowledge about the system (black-box) to produce the result

> this approach is not scalable (that's why the high cost)

It may be opposite, most of the amps follow some classic schematic (e.g. jtm, plexi, princeton) with insignificant changes, so after building digital copies of some limited number of classical amps they can add new one rather fast.

As result, fractal has about 100 high quality models already (average guitarist probably uses 5?).

> the ML approach doesn't require any knowledge

ML approach requires you to capture training data: which is different sound samples with all possible knobs positions (8 knobs per amp in average) + different types of speakers and mics, which is very huge number of variations.

> that's why the high cost

cost is driven by market, ML profiling competitors (kemper, neuraldsp) charge about the same for their devices.

Re: Neural networks emulate any guitar pedal for $120

#70
post #51

Earlier quoted context omitted.

Yes, latency is huge. Modern digital audio stacks in consumer OSes are still completely terrible at this. Not that it's an easy problem to solve. But it's pretty hard to beat elections flowing through an analog circuit, when in the digital side you have to: convert analog to digital, run through the kernel to get to user space, run the bits through the RNN, send back to kernel space, convert to analog and finally sen…

Also we had electronic simulators for various instruments for ages now. Things like Clavinova keyboards Piano or Line 6 Pods simulating Guitar/Bass amps & effects have been out their for decades now. And while they have been quite popular due to the sheer number of sonorities and the convenience they bring (possibility to play with an headset, extremely useful to play at night or in apartments), traditional analog se…

I'd say lower guitar skill ranges (me) get an improved sound from modern digital effects and tools. As the skill gets higher, those effects, especially high compression, mask your style and desired end sound.
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