Members freakinawesome Posted June 19, 2011 Members Share Posted June 19, 2011 Like all amp modelling, GSP1101, AXEfx, PODS, Amplitube? I've often wondered this and while have no desire to attempt to write one myself, I'd love to know how it basically works. Anyone know a site where they talk about ths stuff?Thanks! Link to comment Share on other sites More sharing options...
Members Guitarmonkey55 Posted June 20, 2011 Members Share Posted June 20, 2011 I dont claim to be an expert but I do have a significant math, physics, and programming background and have worked with DSP in engineering applications before. The most common technique in DSP (Digital Signal Processing) is the application of the Fourier Transform, or in the case of discrete digital signals, the Fast Fourier Transform(FFT). This mathematical operation will take a signal and, in a sense, draw you a graph of how much of each particular overtone frequency exists in a signal. Looking at a graph of Amplitude vs. Frequency you see a clear picture of what the fundamental frequency is (what note is playing) and what overtones make up the particular timbre you are hearing (in the case of audio, that is). Using this FFT result you can devise a mathematical formula to add or subtract frequencies in a signal to try to approximate what you originally sampled. Run your clean guitar sound through this formula and you end up with the processed sound. So basically the workflow in a broad general manner of speaking is 1)sample a sound that you want to simulate 2)do an FFT on the sample 3)devise a formula to artificially create this same result 4)process your new signal with this formula Reading up on DSP in general will pretty much nail the process on the head, though probably with considerably more detail than you want. I should also add that this is more an explanation of how to simulate a tone, not necessarily effects. Effects like distortion, reverb, etc all result from creatively manipulating the effects at the sample level, and are a little different. Link to comment Share on other sites More sharing options...
Members freakinawesome Posted June 21, 2011 Author Members Share Posted June 21, 2011 That's great, thanks guitarmonkey! I'll look into it in more depth when I have a chance, at least I know where/what to for look for now. Thanks again for the info man Link to comment Share on other sites More sharing options...
Members The Extremist Posted July 3, 2011 Members Share Posted July 3, 2011 i was thinking about this same thing, wondering if amp modelers actually modeled the internal electronics of an amp and used amp schematics. like using formulas to simulate every resistor and capacitor etc... i have revalver, and it lets you change "internal" amp parameters, which is where i got these thoughts. not sure if they're modeling the overall sound, or actually trying to model the circuit. it would be interesting to model every internal component of an amp digitally, and give the user a sandbox mode where they can just build their own amp from scratch out of the raw materials. im sure we have a long way to go before we get there but its fun to think about. Link to comment Share on other sites More sharing options...
Members stratotak Posted July 9, 2011 Members Share Posted July 9, 2011 If it were purely sampling the actual amp then you would need the amp you want to model to make a amp sim.The guys who put out the free amp sims use schematics of the amp and their ears to model the pre-amp,tone stack..I asked basically same question on Guitar amp Modeling.Where the guy who do all the free stuff hangout at.. http://www.guitarampmodeling.com/viewtopic.php?f=51&t=7006 Link to comment Share on other sites More sharing options...
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