[HN Gopher] Neural networks emulate any guitar pedal for $120
       ___________________________________________________________________
        
       Neural networks emulate any guitar pedal for $120
        
       Author : ushakov
       Score  : 209 points
       Date   : 2021-05-31 10:30 UTC (12 hours ago)
        
 (HTM) web link (hackaday.com)
 (TXT) w3m dump (hackaday.com)
        
       | zabil wrote:
       | This is really cool. I wonder if this can be used to simulate
       | pianos, rhodes and wurlitzer sounds.
        
         | ushakov wrote:
         | i've managed to use the technology in reverse and somewhat
         | successfully undo a effect from audio
        
         | nonsapreiche wrote:
         | I wonder too, but I think the result will not be better than
         | the samples from which you train it.
        
           | ratww wrote:
           | Now that you mentioned samples: I wonder if neural networks
           | will be able to help with polyphonic note detection, so we
           | can trigger MIDI samples using an off-the-shelf guitar or
           | other instruments.
           | 
           | There have been a few recent advancements lately (Boss SY-1),
           | but even the supposedly "ideal" solutions, that require a new
           | polyphonic pickup, are not good at all. I have a Fishman
           | Triple Play and a plugin whose name I forgot, and tracking is
           | frankly terrible.
        
             | PaulDavisThe1st wrote:
             | polyphonic note detection is largely solved at this point.
             | 
             | But "solved" here means "when _not_ doing the analysis in
             | real time ". The realtime solutions are not as good. NN's
             | are not typically great at realtime either, so this may not
             | help very much with this particular goal.
        
               | ratww wrote:
               | The video in TFA is in real time, so I don't believe your
               | assumption is correct.
        
             | nwatson wrote:
             | In which Pat Metheny tries to replace his whole band with
             | guitar-triggered control of real, non-guitar instruments
             | (keyboards, drums, etc) ... "Orchestrion" ...
             | https://youtu.be/KsYEOUKS4Yk
        
               | ratww wrote:
               | Yeah, it's honestly not _that_ good. I think Metheny uses
               | an Axon. Even with those you need to be very careful with
               | your phrasing, you can 't be too fast, you lose a lot of
               | dynamic range and a lot of expressivity, sometimes notes
               | just die, the latency is high...
               | 
               | Here's what Metheny said himself: _" But the guitar-to-
               | MIDI part has always been a problem. It's a question of
               | physics. On input, I sort of have to rush. But I know how
               | to rush. I play ahead."_
               | 
               | It's fun for lots of things, and you can make lots of
               | cool music, but it's still very limited to certain
               | styles, dynamic ranges, phrasing, tempo, speeds...
        
       | IAmGraydon wrote:
       | 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.
        
         | FrankyFire wrote:
         | No, it doesn't. But to be honest, this would be next level.
         | When looking at this, I'm thinking of alternatives and I can
         | only name 2:
         | 
         | 1 - Kemper Profiler
         | 
         | 2 - NeuralDSP
         | 
         | Both of them are above 1000EUR/$. We are talking about 10x the
         | price of this thing. Add some Multi-FX Pedal (like Line6 HX-
         | Stomp) where you put this in the FX-Loop and you end up with
         | something equally good for still half the price.
         | 
         | And in general, its not about what is better, digital or
         | analog. It's about the use-case. In the studio or when noodling
         | around with the knobs when practicing: Real Amps and Pedals.
         | But on stage, you don't play with the settings of your pedals
         | or you want presets. This is where you go digital. No one will
         | notice the slightly different sound there anyway.
        
           | IAmGraydon wrote:
           | I played out live for a decade and absolutely used the knobs
           | on my pedals live. Most musicians I knew with a pedalboard
           | did the same.
           | 
           | That said, if you use a preset based effects setup like
           | rackmount gear, I could see how this would be cool.
        
         | jerrysievert wrote:
         | 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.
        
         | ushakov wrote:
         | not quite there yet, but on possibility is train multiple
         | models and switch between them on the fly
         | 
         | another is add more params to the models to take the knob
         | states into the account when doing predictions (which can
         | impact the performance)
        
       | marcodiego wrote:
       | Isn't any reasonably good DSP able to do same? Or is it learning
       | automatically to mimic the effect?
        
       | magicalhippo wrote:
       | I recently watched a video[1] by Rhett Shull where he compared
       | Neural Capture of a Quad Cortex[2] to real pedals.
       | 
       | I'm not a musician, but even I could easily tell the difference a
       | lot of the time. It didn't sound bad, but there were clearly
       | aspects the Neural Capture failed to, well, capture.
       | 
       | Still, early days.
       | 
       | [1]: https://www.youtube.com/watch?v=4SSOJxZHolc
       | 
       | [2]: https://neuraldsp.com/quad-cortex
        
         | ushakov wrote:
         | GuitarML have a similar video as well
         | 
         | https://www.youtube.com/watch?v=xEOFz3UcDyA
        
           | magicalhippo wrote:
           | Similar-ish but clearly very different. I noticed that in
           | that video he was using the WaveNet model, though apparently
           | the statefull LSTM model performs better[1]. Though even for
           | that you can hear[2] a fairly clear difference.
           | 
           | [1]: https://towardsdatascience.com/neural-networks-for-real-
           | time...
           | 
           | [2]: https://towardsdatascience.com/neural-networks-for-real-
           | time...
        
       | kazinator wrote:
       | Emulate 20 transistors using hundreds of millions of transistors!
        
         | jtriangle wrote:
         | 20 especially shitty transistors to be fair.
        
       | wintermutestwin wrote:
       | 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.
        
         | jtriangle wrote:
         | The AxeFX is old news when it comes to guitar modeling. The
         | newest Kemper firmwares do a much better job, and NeuralDSP's
         | Quad Cortex does an even better job still along with the
         | ability to capture distortion pedals.
         | 
         | Modeling real gear is all fine and dandy, but what really has
         | potential is being able to replicate circuits that aren't
         | viable in the real world, like a tube amplifier on the edge of
         | occilation or one run way over the rated TDP of it's tubes,
         | situations that might provide sonic possibilities that aren't
         | viable long term can now be stable and replicatable long term.
         | Additionally, being able to modify a tone stack in software to
         | provide extra flexibility is very handy.
         | 
         | The Quad Cortex is also slated to receive updates that will
         | allow it to capture modulation effects, and will undoubtedly
         | get better with time as the Kempers did.
        
           | wintermutestwin wrote:
           | >he newest Kemper firmwares do a much better job, and
           | NeuralDSP's Quad Cortex does an even better job still
           | 
           | Umm. You and I are just random people on the internet. I have
           | spent a lot of time trolling the places pro musicians talk
           | about the leading devices and I have found that Fractal is
           | very widely considered to be the best of the best as far as
           | sound quality goes. Kemper is known to be easier to use and
           | Neural is the new kid on the block that has bluetooth, touch
           | screen on device and footswitches that act as knobs. For the
           | limited # of tones you get, it is supposed to sound great.
           | None of those features are advantageous to me at all.
           | 
           | >being able to replicate circuits that aren't viable in the
           | real world
           | 
           | That is definitely something that Fractal does. Considering
           | the two devices you are talking up are based on capturing
           | actual tones from real world devices, I am unsure of your
           | point here.
           | 
           | >capture modulation effects
           | 
           | Modulation and time based effects have been modeled to
           | perfection in the digital realm for a long time now. See the
           | ubiquity of Strymon, etc. Fractal has equally good algorithms
           | and allows incredibly intricate and signal paths as it is an
           | all-in-one device. I have four expression pedals and 10
           | switches that can be programmed to control any parameter I
           | would desire with a couple clicks of a mouse. No other multi
           | effects device brings this degree of controllable complexity.
        
         | ushakov wrote:
         | 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
        
           | wintermutestwin wrote:
           | This is exactly what Fractal has achieved. They took actual
           | amps and modeled the actual circuits. Basically, this work
           | was done for a massive number of amps by one dude. And he
           | sells this device for $2k - which is ~ the cost of a single
           | good tube amp head.
        
           | riku_iki wrote:
           | > 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.
        
             | ushakov wrote:
             | sure, but can it model _my_ amp? i doubt they will ever add
             | it!
             | 
             | correct, ml requires data, but you don't need to capture
             | every possible position to do a good prediction
             | 
             | only a handful would suffice and let's be honest, how many
             | presets do you really need (average guitarist probably uses
             | 5?)
        
               | riku_iki wrote:
               | > sure, but can it model my amp? i doubt they will ever
               | add it!
               | 
               | This is very different and more narrow use-case.
               | 
               | Also they have tone match like forever, you build signal
               | chain close to your amp, then add tone match block, which
               | applies ML to voice your digital signal chain close to
               | recording.
               | 
               | Here is example:
               | https://www.youtube.com/watch?v=hZnZ1nJODLo
               | 
               | Also in this example he didn't profile actual amp, but
               | actual AC/DC recording, and result is very good I think.
               | 
               | > how many presets do you really need (average guitarist
               | probably uses 5?)
               | 
               | But how you find this preset for your signal chain
               | (guitar + speakers)? That's one of big points of
               | frustration with kemper: one needs to go through hundreds
               | profiles (not necessary good quality) to find one which
               | will sound good with his signal chain.
               | 
               | With fractal: you take some basic preset, and change
               | knobs to your tastes and goal as with real amp.
        
         | kazinator wrote:
         | 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.
        
       | hashkb wrote:
       | Can any skeptics weigh in? To me, this kind of tech is centuries
       | away from fooling tone hounds.
        
         | ushakov wrote:
         | See "4.4. Listening Tests" of the research the technology is
         | based on
         | 
         | https://acris.aalto.fi/ws/portalfiles/portal/41964332/Real_t...
         | 
         | those are MUSHRA tests, meaning only skilled listeners are
         | allowed to participate https://en.wikipedia.org/wiki/MUSHRA
        
         | jtriangle wrote:
         | Andersons has a few YouTube videos where the Kemper profiler
         | fools tone hounds enough that you can infer that it's already
         | good enough. The NeuralDSP hardware is of at least similar
         | quality, maybe better in some instances.
         | 
         | Sure if you run a null test these will fail, but in real life
         | it's really up to how honest the tone hound in question is, and
         | if you can trap them into being honest.
         | 
         | If you're talking product viability, something like the Pepsi
         | challenge, double blind testing, would probably be effective
         | marketing.
        
         | sosborn wrote:
         | Tone hounds do a good enough job of fooling themselves.
        
         | Applejinx wrote:
         | 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.
        
           | 52-6F-62 wrote:
           | > You can also think of it as learning to rely on secret
           | weapons
           | 
           | Case in point: the old Neve desks
        
         | PaulDavisThe1st wrote:
         | "tone hounds"? There are many hundreds to many thousands of
         | pedals. Everyone has their own favorites. There is no "right"
         | in this world. There's just as much chance that whatever
         | "error" a modelled pedal may embody is preferred by its users
         | as there is that it will be deemed worse.
        
       | duped wrote:
       | The cool bit about this to me is that $120 in hardware is a the
       | one-off prototyping cost. As a product it could be made much
       | cheaper.
       | 
       | Another benefit to a software defined pedal is that it can
       | express sounds that cannot be replicated in analog. Emulation is
       | boring. Train it to do stuff that I can't buy in a pedal!
        
         | ushakov wrote:
         | but the coolest thing is that you can share and download models
         | of one-of-a-kind amps or effect chains, which cannot be bought
        
           | TrackerFF wrote:
           | That's the business model of Kemper (https://www.kemper-
           | amps.com/)
        
             | ushakov wrote:
             | yes, except you don't need to purchase a $1000+ device
             | 
             | this thing runs on consumer-grade hardware
        
           | duped wrote:
           | Line6 was doing this 10-15 years ago and it wasn't that cool
           | then. Eventide has some tools for it today tool, there's also
           | the Owl, various teensy projects, and of course Kemper.
        
             | leviathant wrote:
             | I've had a Line 6 Guitar Port for about 20 years. It was
             | $99, and emulates amps, cabinets, pedals, console channels,
             | rack effects, etc., admittedly offloading the work into a
             | computer that (at the time) cost about a grand.
             | 
             | Are they perfect emulations? No. Did anyone notice that in
             | my music? No. Would I take that rig on stage? Also no.
             | 
             | It did help me find sounds I liked though, and over the
             | years I've bought hardware equivalents of some of my
             | favorite emulations, and I've bought hardware that goes
             | beyond anything Line 6 can do.
             | 
             | As to whether Line 6 is cool or not, NIN/Trent Reznor
             | toured with Line 6 rigs to sold out arenas 20 years ago,
             | and today the live rigs are managed by the FOH using
             | software emulations that can be automated or managed from
             | on-stage controllers. Maybe you don't think that's cool,
             | but the important takeaway is that you should use the tool
             | that's right for you.
             | 
             | I think it's good to see people tinkering with new ways to
             | reduce the cost around modulating audio signals in
             | interesting ways.
        
       | ushakov wrote:
       | For context, here is the discussion of a previous iteration of
       | the technology on HN
       | 
       | https://news.ycombinator.com/item?id=24740266
        
       | TrackerFF wrote:
       | Sure, but how good will it sound? High quality AD/DA converters
       | alone will cost.
        
       | EamonnMR wrote:
       | There's no link to the vst. It would be neat if it was something
       | you could just drop into your DAW and try to train it in wacky
       | effects chains. The artifacts in it's sound might be really neat.
        
         | ushakov wrote:
         | check out https://github.com/GuitarML
        
       | martinvol wrote:
       | Wow, fantastic. Amazing work!
        
       | andybak wrote:
       | _any_ pedal? That seems far-fetched - one trivial counter-example
       | would be a looper as that requires modal input and state. I also
       | wonder if it can handle complex multi-tap delays.
       | 
       | Can anyone give a rough idea of the actual limitations? I would
       | guess that there is a limit to how non-local the effects it can
       | manage are.
        
         | taneq wrote:
         | If you want to be pedantic it probably can't emulate a guitar
         | pedal that you can tap a representation of a Turing machine
         | into and it will only make a sound if the machine halts.
        
           | shmageggy wrote:
           | You can't create such a pedal in the first place, so...
        
             | marcodiego wrote:
             | You definitely can. You just cannot prove it will always
             | make a sound.
        
             | jdbernard wrote:
             | Yep. Disprove the sweeping generalization by
             | counterexample.
        
             | tiborsaas wrote:
             | The joke is that some pedals can be really complex with
             | menu systems and all kinds of tricky jazz.
        
             | jcelerier wrote:
             | why couldn't you ? the code would just be
             | extern char* turing_machine;         int main() {
             | process_turing_machine(turing_machine);           beep();
             | }
        
         | JD557 wrote:
         | They claim to be using a LSTM, and I believe that any RNN-like
         | architecture should (in theory) be able to learn a loop pedal.
         | 
         | If you aren't familiar with RNNs, think about it like a NN that
         | instead of learning a input -> output function, learns a
         | (input, state) -> (output, newState) function
        
           | lunixbochs wrote:
           | Only if the entire loop audio fits into the RNN's hidden
           | state? Or if you use some kind of external memory mechanism
           | that gives the network access to previous audio.
        
             | titzer wrote:
             | This is the kind of thing where augmenting the NN with an
             | actual raw audio buffer would allow it to mix in some of
             | the signal from the past quite easily.
        
             | jeeceebees wrote:
             | LSTM stands for Long Short Term Memory. It's a recurrent
             | network that learns what and how long things should be kept
             | in its internal state buffer. It doesn't have a fixed state
             | size because it's just learning a nonlinear function that
             | takes an input and a state to an output and a new state.
             | Obviously it can't model _all_ possible, infinite length
             | recurrences, but it can definitely do a pretty good job of
             | approximating long term recurrence relations in complex
             | signals.
        
               | lunixbochs wrote:
               | I don't think that assessment is quite right. The hidden
               | size is fixed - the second argument to Pytorch's nn.LSTM
               | constructor is "hidden_size - The number of features in
               | the hidden state h".
               | 
               | A call to `y, hidden = layer.forward(x)` (where x has a
               | batch size of 1, and an arbitrary length) produces two
               | hidden states of dimensions `(1, 1, hidden_size)`, where
               | hidden_size is the exact number you passed to the LSTM
               | constructor. Those two states represent the long term and
               | short term memory features.
               | 
               | You would need to have an LSTM with hidden_size large
               | enough to store the samples (or a compressed
               | representation) of your entire loop. Not to mention you'd
               | run into other issues with handling the logic around
               | variable length loops based on a pedal toggle.
        
         | keyth72 wrote:
         | ..any pedal
         | 
         | It can't do time based effects such as delay, reverb, flange,
         | chorus, etc. The LSTM can model distortion, overdrive,
         | compression to an extent, and amp circuits (including vacuum
         | tubes).
        
           | keyth72 wrote:
           | But I will say that there is a project out there for time
           | varying effects, but haven't dug into it yet. I believe it's
           | a different method than the LSTM
           | 
           | https://github.com/Alec-Wright/NeuralTimeVaryFX
        
         | ushakov wrote:
         | you could model amplifiers, distortion effects, phasers and
         | flangers, according to CoreAudioML project, which makes this
         | possible https://github.com/Alec-Wright/CoreAudioML
        
           | bottled_poe wrote:
           | You could.. but should you? I appreciate the ingenuity, but
           | tuning this tech is time consuming. I prefer to just carrying
           | on playing my guitar poorly.
        
             | ushakov wrote:
             | you can download models online, no need to train yourself,
             | which i agree is time consuming
        
               | ratww wrote:
               | There's even some potential for a small market of those.
               | Lots of guitar players I know but Kemper models, or
               | convolution impulses.
        
           | duped wrote:
           | You can model most useful nonlinear functions with neural
           | networks, this is unsurprising. You can also use Volterra
           | series. You can even estimate/measure the Volterra kernel
           | then train a NN to model it instead of dealing with the
           | computational complexity of generalized convolution for
           | nonlinear dynamic systems.
           | 
           | The hard part is that there are some fundamental limitations
           | to deal with. The biggest is aliasing - distortion effects in
           | particular deal with enormous amounts of distortion (> 100%
           | THD) which creates spectrums far outside the range of
           | hearing. Digital audio systems need to have high orders of
           | oversampling to prevent audible aliasing (8-16x is not
           | unheard of!).
           | 
           | After aliasing is memory. It's too early in the morning for
           | me to do math but I'm almost certain you can't model a looper
           | with a causal NN that has less internal state memory than the
           | length of your loop. Doing so is dumb anyway, since loopers
           | are pretty trivial and their biggest cost is memory. Same
           | goes for digital delay and modulation effects, the algorithms
           | are not expensive.
        
             | marcan_42 wrote:
             | Now I wonder if a NN would be able to learn a nonlinear
             | effect without aliasing, even if run at the original sample
             | rate. Oversampling and filtering are, after all, things
             | that could become part of the model too. Perhaps it can
             | learn to approximate them with less CPU cost than doing it
             | for real.
        
               | duped wrote:
               | Oversampling requires producing more output information
               | than input information. It would be incredible for a NN
               | to realize a system that could do this without requiring
               | more memory and CPU cycles than a good oversampling
               | algorithm, which can be derived analytically with various
               | definitions of "optimal."
               | 
               | A 3rd or 4th order polynomial interpolator is pretty darn
               | good and doesn't need a NN to find the coefficients.
        
       | fermigier wrote:
       | Uli Behringer in a box ;)
        
       | krueger71 wrote:
       | I'm guessing a Hi-Z input before this contraption could improve
       | the tone and do the pickups of the guitar or bass justice. A
       | dedicated buffer pedal or just a pedal with buffer bypass
       | perhaps?
        
         | DarrisMackelroy wrote:
         | Most definitely. A radial reamp DI would improve the tone on
         | this rig noticeably. Even if you didn't use reamp specific
         | hardware, using 2 direct boxes to match impedance on the input
         | and output of the Pi would help.
        
         | sirtaj wrote:
         | Yes I was surprised to see the guitar signal going in directly.
         | A simple DI box would improve the sound noticeably.
        
       | musicale wrote:
       | For analog pedals, I'd expect better results from circuit
       | modeling.
       | 
       | Given the wide (and very non-linear) range of settings of a
       | typical pedal, as well as interaction (impedance, etc.) with a
       | real guitar and amplifier, it seems like it would be a pain to
       | get all of the training data.
       | 
       | For a digital pedal, running the actual (e.g. Eventide) DSP code
       | is just going to be better than some ML approximation.
       | 
       | On the other hand, I've been a bit dissatisfied with amplifier
       | and cabinet models based on traditional DSP and physical modeling
       | approaches, so maybe neural networks could fill in some of the
       | gaps.
        
         | sillysaurusx wrote:
         | ML dilettante here!
         | 
         | I wouldn't discount ML. The nonlinearities are the bread and
         | butter of modern ML models. In fact, two linear layers without
         | a nonlinearity inbetween is equivalent to one big linear layer.
         | So nonlinearities are required.
         | 
         | To put it another way, I would gladly bet any reasonable sum of
         | money that in a double blind test, the listener wouldn't be
         | able to tell the difference from a genuine guitar pedal. (Not
         | necessarily _this_ pedal, but I suspect ML will model the
         | effects more than adequately for human hearing precision.)
         | 
         | FWIW, I say this as someone who used to argue that graphics
         | programmers were doing gamedev all wrong because they weren't
         | modeling light, they were approximating light. ML models were
         | the way out.
         | 
         | I also think much of the problem is that ML devs often don't
         | have traditional signal processing experience, so they haven't
         | been modeling signals in quite the right way. (I'm trying to
         | rectify that a bit with my FFT tutorials: https://twitter.com/t
         | heshawwn/status/1398796224921321472?s=2...) It remains to be
         | seen, but Fourier space has recently been making strides in ML,
         | and it's likely _much_ easier for a model to approximate a
         | nonlinear waveform in frequency space than as a raw waveform.
         | 
         | To put it another way, if human speech is getting to the point
         | where ML models can trick people, what are the chances that a
         | future model won't be able to do it for guitars?
        
           | ushakov wrote:
           | actually, the researchers of aalto university (now at neural
           | dsp), who pioneered the guitar ml technology, were working on
           | speech initially and did this one as a side project
           | 
           | source: https://m.youtube.com/watch?v=WLTzbEKTxhk
        
         | ushakov wrote:
         | in disbelief? See "4.4. Listening Tests" in the paper the
         | technology is based on
         | 
         | https://acris.aalto.fi/ws/portalfiles/portal/41964332/Real_t...
         | 
         | those are MUSHRA tests, meaning only skilled listeners are
         | allowed to participate https://en.wikipedia.org/wiki/MUSHRA
         | 
         | TLDR: the results of neural networks for given amplifier models
         | are rated as "excellent" by the listeners, some even
         | outperformed the reference!
        
       | ushakov wrote:
       | have i mentioned yet that training only takes ~30 minutes and you
       | only need ~3 minutes of data?
        
         | jtriangle wrote:
         | Could it work on a live amp like the Kemper or a quad cortex?
         | And can the models be exported and shared?
         | 
         | Because if those two things were squared away, I could see this
         | being an extremely viable project.
        
           | ushakov wrote:
           | yes! for training the model you'd need a separate
           | computer/server though
        
       | patfla wrote:
       | I stopped reading at the first sentence:
       | 
       | "It's a well-established fact that a guitarist's acumen can be
       | accurately gauged by the size of their pedal board- the more
       | stompboxes, the better the player."
       | 
       | As both a software engineer and a guitarist, I'd say the opposite
       | is true. Or at least truer. You can't do math-rock without a lot
       | of pedals but the hard part is to acquire the chops. A lot of
       | pedals, and production effects generally, quickly become cliches
       | and it's like dropping down a musical black hole. Someone like
       | Hendrix could take a new effect (superset of pedals) and make it
       | work musically brilliantly but most pedal users buy the pedal to
       | get someone else's sound.
        
         | ushakov wrote:
         | don't take it too literally, i'm pretty sure this was meant as
         | a sarcastic joke by the author :D
        
           | patfla wrote:
           | Maybe I should have read past the first sentence. The joke's
           | on me.
        
         | awsanswers wrote:
         | I believe that was sarcasm
        
       | archsurface wrote:
       | I bet not the miku.
        
       | notum wrote:
       | As much as I'm torn with my feelings about nVidia as a company,
       | especially recently with their attempts to artificially limit
       | hardware you own, I must admit Jetson family is incredibly
       | capable and very well executed.
       | 
       | I've been using Jetsons as RasPi replacements wherever I can,
       | they are not only more capable but also much more reliable than
       | RPI4s, in my not so limited experience.
        
         | Bancakes wrote:
         | Extremely expensive. Or overpriced?
        
           | notum wrote:
           | I wouldn't say that. 2GB dev kit is $50 depending on where
           | you buy them. That's much more bang for the buck, even if you
           | opt out using the tensor cores they were designed for.
        
             | 1996 wrote:
             | They sorely lack m2 for high throughput storage.
             | 
             | A board with a m2 port costs an extra $300 and only exists
             | since last year: https://antmicro.com/blog/2020/04/updated-
             | jetson-nano-xavier...
             | 
             | It should have been standard and by default from the
             | beginning.
        
               | notum wrote:
               | M2 port would have been awesome! I believe the comment
               | stating Jetsons were expensive was made in comparison
               | with the RPI4, which also lacks an m2 slot. I really do
               | find Jetons much more affordable when performance is
               | taken into account, again, Tensor aside.
               | 
               | They can also boot from USB3 as of recently, which boosts
               | storage access speed tremendously.
        
       | [deleted]
        
       | Applejinx wrote:
       | ...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.
        
         | keyth72 wrote:
         | ...At mp3 quality
         | 
         | As the creator of this project I can assure you that the audio
         | used here is at least CD quality (44.1kHz 16bit). With the
         | HiFiBerry hat the digital audio comes in at 24bit/192kHz. The
         | NeuralPi DSP processes the audio at 44.1kHz with 32 bit
         | floating point precision. No reason the sample rate can't be
         | higher though. Elk OS claims latency is less than 1ms, but I'd
         | like to test and see exactly what the latency is running the
         | plugin. As a guitarist, I can't tell the difference between
         | this and an analog effect.
         | 
         |  _runs and ducks for cover_
        
           | Applejinx wrote:
           | No worries, not worth throwing anything at you. Carry on <3
        
           | jcims wrote:
           | I wonder if it's possible to build a neural net that consists
           | of layers of simulated passives and simple ICs.
        
         | montroser wrote:
         | 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 send to an output.
         | 
         | In order to be competitive with a 1980s guitar pedal, you have
         | to do all of that in under ~10ms latency, and that's just
         | really hard still.
         | 
         | Even though we carry around these super computers in our
         | pockets these days, there are still some things left where
         | analog still beats the pants.
        
           | karmakaze wrote:
           | 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.
        
           | titzer wrote:
           | Yes, latency is really important, though it is important to
           | note that digital signal processing doesn't need that huge
           | stack. In fact, audio DSP chips have at least 25 years of
           | history and the result is that today you can get things like
           | the Vox AC30 which is a digital headphone amp--all digital--
           | that has no perceptible latency. That one in particular,
           | sounds pretty darn good, for just being a single battery-
           | powered chip!
           | 
           | > In order to be competitive with a 1980s guitar pedal, you
           | have to do all of that in under ~10ms latency, and that's
           | just really hard still.
           | 
           | Well, don't use a whole PC with software stack. A custom
           | embedded solution with DSP can easily manage.
           | 
           | > Even though we carry around these super computers in our
           | pockets these days, there are still some things left where
           | analog still beats the pants.
           | 
           | Again, it's not digital vs analog, it's massive software
           | stack versus embedded hardware/software solution.
        
           | smoldesu wrote:
           | > Modern digital audio stacks in consumer OSes are still
           | completely terrible at this. Not that it's an easy problem to
           | solve.
           | 
           | Honestly, the only OS that's truly bad at this is Windows.
           | DirectSound is laggy and highly limited in it's capabilities,
           | and even a nice ASIO won't fully alleviate your issues. Your
           | best bet is to get a DAC and hope for the best. Besides that,
           | I've found Linux and MacOS to be very similar in terms of
           | latency, out of the box. However, I've found that tuning
           | Linux with a custom low-latency kernel absolutely destroys
           | CoreAudio's latency. Given that it's something most people
           | won't be doing, I think it's fair to say that both OSes are
           | tied, but I still give the edge to Linux for having a more
           | modular and adaptable sound backend.
        
           | hashkb wrote:
           | Also, the competition is not against vintage analog gear.
           | Modern analog gear is having a true Renaissance, and this
           | community can afford to support the Wampler's of the world. I
           | don't understand the modelling camp at all, their stuff just
           | doesn't sound good, nor is there any joy in working with it.
        
             | Applejinx wrote:
             | I feel the same but it's hell convincing the reductionists
             | that they haven't got 'the thing, and the whole of the
             | thing' in their little emulation.
             | 
             | There's also another element: if you have, say, a vintage
             | Fender Champ and a Klon (or whatever) it's because you mean
             | to project different expressions through your string
             | handling and note-playing. At that level you've made a best
             | effort to produce the most emotionally transparent and
             | responsive signal chain, which you will then not think
             | about once you've got it turned on and tweaked: ALL the
             | settings are liable to sound 'good' and respond for you.
             | 
             | The modeling approach is so often "This is exactly that,
             | but better, because here are twelve other Fender Champs and
             | models of Klon to choose from!" and when the first claim
             | isn't as true as we would like, and the second is a
             | distraction and time-sink, that's not great.
             | 
             | I can tell when I've chosen wrongly in my music-making
             | tools, because I flat-out stop making music. Even in a
             | dilettantish way: it just stops being a thing. That's a
             | concern.
        
               | crmd wrote:
               | I have this problem just with the torpedo captor x
               | speaker simulator. At first I thought it was a game
               | changer for apartment guitar playing. However the
               | plethora of speaker, mic, and placement options makes me
               | spend way too much time browsing and fussing rather than
               | playing. I'd rather have one decent cab in a room where I
               | can turn up the volume rather than hundreds of simulation
               | options.
        
               | tigeba wrote:
               | FWIW, I have been using the Captor X as a quick tracking
               | and editing tool. I will record the DI + Captor track. It
               | can be a bit easier to comp the DI parts. Then later I go
               | back and re-amp them thru my amps and speakers. I do have
               | the benefit of a few nice amp and cabinet options and
               | decent soundproofing, but it helps keep the ear-bleeding
               | levels down to a minimum. That has kind of helped me
               | avoid fiddling with Captor settings endlessly.
        
           | bentpins wrote:
           | How huge is the latency? It's using Elk Audio OS, claiming
           | 1ms roundtrip. I doubt this usage gets that low but I
           | wouldn't be surprised if it was doing alright
        
           | slver wrote:
           | A smartphone doesn't have super-low latency audio only
           | because its makers have not set out to have it.
           | 
           | The only strength of analog processors is that they're
           | dedicated. That an iPhone SoC and run dedicated audio-only OS
           | on it, and there we go.
        
           | tigeba wrote:
           | I could see using something like this on a pedalboard in
           | pedal form if you had the latency around <5ms or so for sure.
           | I use a combination of analog and digital effects combined
           | with analog amplifiers. I still prefer the actual amps quite
           | a bit compared to simulations, but the simulations are a lot
           | less of a pain. Recently I have been using a combination load
           | box / cabinet simulator and I think those types of devices
           | can really deliver in terms of tone and convenience.
        
           | kakwa_ wrote:
           | 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 setups
           | remain strong.
           | 
           | Playing on an analog setup still is more pleasant and more
           | expressive IMHO, in particular "simulators" tend to mask the
           | attack when hitting a note, and hides a lot the
           | tension/crispation in the hands/fingers when playing, leading
           | to potential bad habits, specially for people learning to
           | play an instrument. Analog to digital and digital to analog
           | conversion definitely lead to loses in expressiveness.
        
             | ushakov wrote:
             | i totally agree
             | 
             | traditional methods were successful in emulating sounds,
             | but they fail short at replicating the feel and response of
             | the hardware they're trying to replicate
             | 
             | that's why you need neural networks!
        
             | hugey010 wrote:
             | 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.
        
           | jiofih wrote:
           | > Modern digital audio stacks in consumer OSes are still
           | completely terrible at this
           | 
           | This has been solved for over a decade. Linux is a bit tricky
           | but MacOS and Windows have native low latency drivers. There
           | are also a ton of digital effects units running at 0ms on the
           | market.
        
         | dkarras wrote:
         | >...at MP3 quality.
         | 
         | Not necessarily... why? We have been very successful with amp /
         | pedal modeling through regular DSP methods. You'd be very hard
         | pressed to find an album that doesn't use one nowadays. What
         | makes NN methods fundamentally different?
         | 
         | >it's not going to be nice to play through if it's incurring
         | any significant latency.
         | 
         | Yes but this is a non issue for many of the current systems,
         | actually since a couple decades ago. 1-2ms latency is pretty
         | achievable, especially with a RT kernel. That is the natural
         | latency of a sound source about 1 meter away from you.
        
         | smoldesu wrote:
         | In all fairness, it's running on a Raspberry Pi. There's plenty
         | of ways you could improve latency and audio quality just by
         | scaling the hardware to fit your needs. Plus, it's not like
         | someone's going to flip their shit when they realize that one
         | of the electric guitars was recorded at 44.1khz instead of
         | 48/96/192khz
        
           | PaulDavisThe1st wrote:
           | Improving CPU speed rarely has anything to do with audio
           | processing latency unless you're close to overloading the
           | CPU.
        
         | tpmx wrote:
         | MP3 @ 320 kbps is fine. Latency is a different thing. Also it
         | seems like you're dismissing this without knowing anything
         | about the actual latency (or sound quality).
        
         | ampdepolymerase wrote:
         | Just switch the Pi for a FPGA and the problem should be fixed.
        
           | IshKebab wrote:
           | 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.
        
             | jeffreygoesto wrote:
             | I would go even further and say that an FPGA does not RUN
             | something, it IS something.
        
         | URSpider94 wrote:
         | There is no reason why this would run at "MP3 quality", given
         | that it would be a really bad idea to compress the audio data
         | before running it through an algorithm. I would expect it's at
         | minimum CD quality, and perhaps better, depending on the
         | fidelity of the A/D and D/A stages and the bandwidth of the
         | algorithm.
        
       | duosonic wrote:
       | Honest question: if you're a musician, what is the appeal of
       | digital modeling? Is it purely affordability/accessibility, or
       | are you drawn to it because it would create different sonic
       | possibilities that you couldn't get from the original?
        
         | URSpider94 wrote:
         | You mean, besides the appeal, what is the appeal? As an artist
         | and a musician, you can have access to close approximations of
         | sounds that would require a warehouse full of amps and dozens
         | of pedals, costing tens of thousands of dollars - all in a Pi
         | project box. That's not just a little bit of affordability and
         | convenience.
        
           | duosonic wrote:
           | And I certainly don't mean to sound dismissive about the
           | possibilities that creates! It's a huge factor and I would
           | see it being akin to how the rise of "pro-sumer" home
           | recording equipment played a huge role in underground punk
           | music.
        
         | humbledrone wrote:
         | Speaking for myself, the accessibility and convenience is a
         | huge part. Instead of lugging around a 60 pound fragile
         | finnicky pedalboard, I just throw my Helix in a backpack and am
         | good to go. It has way more pedals in it than I could fit on a
         | real pedal board, and I can also switch presets with the tap of
         | my foot (including rewiring all the connections between pedals,
         | changing their order, swapping pedals, swapping amps, etc).
         | 
         | And yeah the sonic possibilities are endless. On a physical
         | pedalboard, it's pretty involved to rewire everything to change
         | the routing, or add/remove pedals, etc. With the digital
         | modeling ones, this all becomes trivial and you can try all
         | kinds of different setups much more quickly, save them and go
         | back later, share them with friends, etc.
         | 
         | All that said, it's kind of like asking an acoustic guitarist
         | in the 1950s why they would use an electric guitar. Electric
         | guitars obviously have lots of advantages, but it's not like
         | people stopped playing acoustic guitars. I still think real
         | analog pedals are cool, they're fun to collect, in some cases
         | they sound better, etc. And sometimes you don't need the mega-
         | flexibility -- if you have a 4-pedal setup that does "your
         | tone" maybe that's all you ever need.
        
           | duosonic wrote:
           | I think those are perfectly valid reasons for going with
           | emulation.
        
         | keyth72 wrote:
         | Flexibility and affordability. As a guitar player, if I walked
         | into a room and on one side there's a perfect digital emulation
         | of a Marshall stack, and on the other side there's and actual
         | Marshall stack, I'd go for the real thing every time. But the
         | reality for most musicians, myself included, is that I wouldn't
         | be able to or wouldn't be willing to pay that much for one. Now
         | if I had a whole library of digital amps/pedals to try, then I
         | could find something I like best and go get the real thing. I
         | don't see digital as replacing analog, only enhancing it. It's
         | also nice to be able to plug in headphones, and from a laptop
         | or pedal that takes up much less space.
         | 
         | But as an engineer I just nerd out over all of it. Analog.
         | Digital. If it makes good music it's all cool to me.
        
         | ushakov wrote:
         | portability is a big one
         | 
         | you can run the produced models in browsers, on mobile, on
         | embedded hardware such as in this case and even on calculators
         | (joking)
        
         | wintermutestwin wrote:
         | >are you drawn to it because it would create different sonic
         | possibilities that you couldn't get from the original
         | 
         | That's my primary motivation. On my AxeFx, I have signal chains
         | that are impossible with real gear. If I want to tweak that
         | chain, it is a couple clicks of a mouse. I have four expression
         | controllers and 10 foot switches that are tied to different
         | parameters. I can tweak this functionality on the fly. All in a
         | single $2k box.
         | 
         | Beyond all, tube amps are stupid for bedroom players as they
         | generally require gig level volume to get the killer tonez...
        
           | lasftew wrote:
           | I deliberately bought quite a limited but good sounding 4W
           | tube amp for bedroom practice (Vox AC4). Having only a
           | handful of easily understood knobs allow me to focus on my
           | playing.
           | 
           | I have had modeler amps in the past, but every so often I'd
           | just nerd away with the dozens of available amp models and
           | the myriads of settings, and come out with the dissatisfied
           | feeling of having just wasted a lot of time instead of
           | engaging with music.
           | 
           | I find modelers have their place when it comes to replacing a
           | set of analogue pedals, which is the reason I traded my three
           | Boss pedals (compression, reverb, delay) for a Boss
           | GT-1000Core. Overkill for my purpose, as I really never use
           | any amp sims, cab sims, of any of the advanced signal chain
           | stuff that the device is capable of. I just have one patch
           | with my three pedals for practice, going into the AC4,
           | occasionally turning the same knobs as on the analogue
           | versions, but enjoying that I now have built-in a tuner as
           | well :-)
        
       | carlob wrote:
       | I wonder how it deals with dynamic range. I've always been told
       | that one shouldn't run an electric guitar directly through a
       | stereo because the peaks might fry it. So I would expect that
       | whatever comes out of the RPi doesn't have much dynamic range
       | anyway so computer speakers would be ok, but sound would be kinda
       | meh.
       | 
       | Am I missing something?
        
       ___________________________________________________________________
       (page generated 2021-05-31 23:01 UTC)