Re: [music-dsp] Uses of Fourier Synthesis?
It's taken a lot of messages before I had the idea some people were able and willing to understand that sample reconstruction is an issue/potential problem. I still don't have the idea that many are willing to talk about the effects of pretty much *any* DSP operator in actual effect, instead of in a rather fantasy full theoretical realm where DSP operations are perfect and the results as much golden as many advertisement campaigns also make certain product appear golden. Recently I've been using some high quality Yamaha #analog# mixer, and using various very good convertors (which I also compared with each other) and very well (neutral) recorded digital works from HDTracks (the recent music they digitized IMO doesn't suffer anymore from Dolby and Noise Shaping issues, so a big thumbs up for that), playing music and messing with analog equalizers and compressors etc. is great fun, in no way directly comparable to any DSP I've heard here, so when I started my FFT based low-mid and mid-frequency averaging signal chains I've presented some of here, I was interested in if I could still find the matches present in the A-grade studio products, and no surprise: what signal came out of my main monitoring system was predictable, and free from things other than what I'd expect. In fact, I tried a bit of a new trick I'd planned, which is to take an FFT averaged signal, mid frequency range filtered and noise-gated (like I've presented here a while ago), used a separate 384kHz up-sampled DA convertor for that signal, and added an improvised *analog* noise gate, such that the sample reconstruction products that accompany most DA convertor output signal was reduced and changed in (analog) shape by the analog noise gate. That too had the effect I'd hoped for: in the sensitive mid range, the digitized music, which I strongly suspect has a prepared averaged signal component of more or less the nature I anticipate, the clarity and rest of the music sounding was quite improved. I'm aware that the chances of finding the proverbial fish with the golden ring while trawling these undeep DSP waters are slim, but I prefer that a wide range of people and interested parties have the ability to know a bit better which sciences these subject are based on. And that most persons will have some reasonable doubt when facing all too bold statements concerning subjects long existing in the (pro) recording world and digital effect makers of name and fame, in that the main design lines of chief architects of the designs involved were devoid of considerations for, and ignorant in the field of sampling/reconstruction errors, integral and averaging related harmonic and transient inter modulation distortion, and wouldn't have designed system after system already with attention for management of loud sound reinforcement, and recordings with elements dealing with the Equal Loudness Curves for satisfactory playing back at various volumes. So, for whom it might interest: FFT based filtering or synthesis is usually involving signal effects based on the length of the FFT, either in FIR or IIR apps. An FFT acting upon a range of samples followed by and IFFT, give or take some FFt architectural considerations and evidently bit-depth considerations, will give you back the original set of samples, exactly. Pretty much anything you do to the Amplitude+Phase data in between the FFt and the IFFT will have side effects you might not anticipate. FFTs are no miracle machinery which magically solves the infinite length sinc function integral properly for a signal you feed through it, so for instance signal integrals made with the use of the FFT can still be considerably off because you didn't properly sinc filter in between the samples. Just so you know. It might also be interesting to distinguish various frequency ranges when using some sort of FFT filter with audio signals: as many here will know, low frequencies will not be detected accurately, and transient will be taken for low frequency components all the time. Mid frequencies are a bit averaged mostly, and the number of waves fitting in the FFT length is such that on the one hand the frequency discernment is average, and on the other hand short wave element will get averaged. High frequencies will be discerned by the FFT operation up to the Nyquist rate, but there's no guarantee that the brick wall filtering you might expect from the FTT is actually there (it isn't that much, and there is no inherent oversampling in the FFT), and of course, as many will know, fast changes in the high frequency components will get quite a bit averaged. Theo V. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
What is the usual technique for simulating plucked strings? As already mentioned in the thread, additive synthesis can be used for this. Here is an example using only sinusoidal oscillators: http://www.freesound.org/people/jaiserpey/sounds/165444/ The key is the amplitude envelopes used for each oscillator. In the example above I used Cellular Automata to generate those amp. envelopes, using also a technique for sound design called Histogram Mapping Synthesis (HMS). A recent paper about the HMS technique has been published in the Computer Music Journal. In the link above there is a conference paper explaining the technique especifically for the design of plucked string-like sounds. Jaime Serquera De: Alan Wolfe alan.wo...@gmail.com Para: A discussion list for music-related DSP music-dsp@music.columbia.edu Enviado: Domingo 5 de abril de 2015 20:45 Asunto: Re: [music-dsp] Uses of Fourier Synthesis? Interesting, thanks for the info! What is the usual technique for simulating plucked strings? (: On Apr 5, 2015 10:36 AM, Peter S peter.schoffhau...@gmail.com wrote: On 05/04/2015, Alan Wolfe alan.wo...@gmail.com wrote: I was wondering, does anyone know of any practical or interesting uses cases of Fourier synthesis for audio? You can use it for additive synthesis and spectral oscillators. I can already make bandlimited square, saw and triangle waves but was hoping for something like guitar strings or voice, or something along those lines. You can create vocoder type sounds using Fourier synthesis (assuming that's what you meant by 'voice'). For guitar strings - I wouldn't use that approach (though you might come up with some convoluted time-varying formula that sounds simlar to some plucked string, but that's not typically how plucked sounds are created). Someone shared photosounder with me, which treats pictures as a spectrogram and lets you hear the images. https://www.youtube.com/watch?v=W8MCAXhEsy4 That's pretty interesting, but anyone else know of any other practical or interesting audio use cases? Spectral morphing? -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
On 4/5/15 5:21 PM, Theo Verelst wrote: In the context of synthesis, or intelligent multi sampling with complicated signal issues, you could try to make the FFT analysis and filtering a targeted part of the synthesis path, so that the playing back of samples contain variations and sample information that can be picked up and transformed by a FFT based signal path element. In some form (not exactly as I described in general terms) I believe this is the case with the Kurzweils. uhm, i worked for Kurz from 2006 to 2008, specifically on the synthesis component of the chip they used in the PC3. while in off-line note analysis, there might be all sorts of frequency-domain stuff going on, i can tell you for sure there is no FFT-based signal path element in the real-time synthesis process. (and saying so might have been saying too much so i won't be any more specific. but i'll say it might be simpler than a particular guess.) there are real limits to what can be done in real time, specifically if you want 128-voice polyphony. -- r b-j r...@audioimagination.com Imagination is more important than knowledge. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
On Sun, Apr 5, 2015 at 3:32 PM, robert bristow-johnson r...@audioimagination.com wrote: On 4/5/15 5:21 PM, Theo Verelst wrote: In the context of synthesis, or intelligent multi sampling with complicated signal issues, you could try to make the FFT analysis and filtering a targeted part of the synthesis path, so that the playing back of samples contain variations and sample information that can be picked up and transformed by a FFT based signal path element. In some form (not exactly as I described in general terms) I believe this is the case with the Kurzweils. uhm, i worked for Kurz from 2006 to 2008, specifically on the synthesis component of the chip they used in the PC3. while in off-line note analysis, there might be all sorts of frequency-domain stuff going on, i can tell you for sure there is no FFT-based signal path element in the real-time synthesis process. (and saying so might have been saying too much so i won't be any more specific. but i'll say it might be simpler than a particular guess.) there are real limits to what can be done in real time, specifically if you want 128-voice polyphony. Theo was probably referring to the K150 - the only FFT based product Kurzweil made. His statements approximate how it works. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
All harmonics (thus, not that many to compute, especially as most fade out to inaudibility pretty quickly), and not evolving (-just- like with karplus strong, which is pretty much a single-cycle self-filtering over time) It can sound exactly the same, with the added benefit that you have full control on the filtering. -Message d'origine- From: robert bristow-johnson Sent: Sunday, April 05, 2015 9:23 PM To: A discussion list for music-related DSP Subject: Re: [music-dsp] Uses of Fourier Synthesis? On 4/5/15 3:11 PM, Didier Dambrin wrote: I've created plucked strings using additive (not FFT), and it sounds the same as a Karplus Strong, but with more control. So it's definitely doable. The key is: all oscillators have to be phase-unrelated, or it won't sound metallic. are the oscillators harmonic? or not quite harmonic? if the former, do the relative phases change while the note evolves? -- r b-j r...@audioimagination.com Imagination is more important than knowledge. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp - Aucun virus trouve dans ce message. Analyse effectuee par AVG - www.avg.fr Version: 2015.0.5863 / Base de donnees virale: 4321/9462 - Date: 05/04/2015 -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
On 06/04/2015, robert bristow-johnson r...@audioimagination.com wrote: It can sound exactly the same, with the added benefit that you have full control on the filtering. lemme understand the claim: Karplus-Strong can be made to be perceptually identical to the straight sample playback of a particular plucked-string instrument? To me it sounded more like, creating plucked strings using additive synthesis may sound exactly the same as Karplus-Strong. Thus the envelopes of the individual partials give full control on the filtering, if I understand right. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
That's not at all what I was saying. I only wrote that additive synthesis could be used for an identical result to a KS, with better control on the filtering. -- It can sound exactly the same, with the added benefit that you have full control on the filtering. lemme understand the claim: Karplus-Strong can be made to be perceptually identical to the straight sample playback of a particular plucked-string instrument? i have to think about that one. it seems to me that every overtone decay would be strictly exponential, although different overtones can have different alphas and decay at different rates. but you would have to modify K-S a bit more, like have *two* precision delay lines in series and two feedback paths in order to have an envelope that would increase in time before it begins to decay exponentially. or maybe three precision delays with three feedback paths to have a natural tremelo on some harmonic as it decays. i dunno. r b-j -Message d'origine- From: robert bristow-johnson Sent: Sunday, April 05, 2015 9:23 PM To: A discussion list for music-related DSP Subject: Re: [music-dsp] Uses of Fourier Synthesis? On 4/5/15 3:11 PM, Didier Dambrin wrote: I've created plucked strings using additive (not FFT), and it sounds the same as a Karplus Strong, but with more control. So it's definitely doable. The key is: all oscillators have to be phase-unrelated, or it won't sound metallic. are the oscillators harmonic? or not quite harmonic? if the former, do the relative phases change while the note evolves? -- r b-j r...@audioimagination.com Imagination is more important than knowledge. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp - Aucun virus trouve dans ce message. Analyse effectuee par AVG - www.avg.fr Version: 2015.0.5863 / Base de donnees virale: 4321/9462 - Date: 05/04/2015 -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
On 4/5/15 10:15 PM, Didier Dambrin wrote: That's not at all what I was saying. I only wrote that additive synthesis could be used for an identical result to a KS, with better control on the filtering. please accept my apology. i did not correctly grok what you were saying Didier. of course additive synthesis can make an identical result to *any* other synthesis method as it can pretty much create an identical result to any sound, musical tone or otherwise. i'm sorry for misunderstanding and misinterpreting what you wrote. bestest, r b-j -- It can sound exactly the same, with the added benefit that you have full control on the filtering. lemme understand the claim: Karplus-Strong can be made to be perceptually identical to the straight sample playback of a particular plucked-string instrument? ... -- r b-j r...@audioimagination.com Imagination is more important than knowledge. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
Hi Specifically for the FFT: it would have to be a synthesis form tending to have changes in many harmonics over the time of a IFFT interval, where the harmonics are an integer of the base frequency. That's the most logical answer, even though it only talks about the IFFT. Like some here suggested you could do signal analysis with the forward FFT to create frequency samples, or real time effects, or parts thereof, but that wasn't the question. Probably it is also logical to look at applications of accelerated computing for (I)FFTs, as it were to make use of the fastest (I)FFTs around to make some form of synthesis with, which would make the(I)FFT preferable over other frequency analysis/synthesis tools, which is probably part of history. In the context of synthesis, or intelligent multi sampling with complicated signal issues, you could try to make the FFT analysis and filtering a targeted part of the synthesis path, so that the playing back of samples contain variations and sample information that can be picked up and transformed by a FFT based signal path element. In some form (not exactly as I described in general terms) I believe this is the case with the Kurzweils. Finally, you could build in pro-mixing telephone line sounds that a complex mix setup can detect and make Equal Loudness Curve corrections and even DAC (Signal Reconstruction) Transient Inter Modulation corrections with. Playing with the FFT in a sense common in sciences can be of use to all kinds of approximations and components of a digital signal path requiring fast frequency analysis, like speech coding in the 80s. I'm sure I could come up with some interesting uses for my own string simulator software, and a dozen other fun computations, with or without good success, but I think work is more interesting where the analysis of synthesis is done that prevents loudness wars and all kinds of ugly and distorted signals. But that's hard, I've not seen many people work on that. T.V. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
On 4/5/15 5:02 PM, Didier Dambrin wrote: All harmonics (thus, not that many to compute, especially as most fade out to inaudibility pretty quickly), and not evolving you mean the phase (let's say relative to the oscillator with the fundamental) is not changing while the note evolves? certainly the amplitudes of these oscillators are evolving according to some envelope. (-just- like with karplus strong, which is pretty much a single-cycle self-filtering over time) yup, BUT, with Karplus-Strong, there are two filters in the feedback loop (and they can be teamed-up and called a single filter, if you want). one filter is to get a fractional-sample precision delay and the other is a low-pass filter so that higher overtones die away faster than the lower. now we can do everything in a phase-linear way, so that the phase delay of either filter is independent of frequency (BTW, phase delay is what's salient in Karplus-Strong rather than group delay). to keep it phase linear, you would have to use some kinda polyphase FIR interpolation to get the fractional sample delay and another FIR implementation of the LPF. and Karplus and Strong depicted the latter in their original CMJ article. if it's all phase-linear, the overtones are harmonic. but, you *could* use an IIR LPF and an IIR APF for the fractional sample delay. then the loop delay will be slightly different for the different overtones and the frequency of those overtones will not be precisely harmonic. i would imagine for realistic strings, one would want the loop delay to be less for higher frequencies than for lower frequencies, thus tuning the higher overtones sharper than their precise harmonic value. BTW, i've always considered waveguide synthesis to **be** the method of physical modeling. maybe i'm missing something basic. It can sound exactly the same, with the added benefit that you have full control on the filtering. lemme understand the claim: Karplus-Strong can be made to be perceptually identical to the straight sample playback of a particular plucked-string instrument? i have to think about that one. it seems to me that every overtone decay would be strictly exponential, although different overtones can have different alphas and decay at different rates. but you would have to modify K-S a bit more, like have *two* precision delay lines in series and two feedback paths in order to have an envelope that would increase in time before it begins to decay exponentially. or maybe three precision delays with three feedback paths to have a natural tremelo on some harmonic as it decays. i dunno. r b-j -Message d'origine- From: robert bristow-johnson Sent: Sunday, April 05, 2015 9:23 PM To: A discussion list for music-related DSP Subject: Re: [music-dsp] Uses of Fourier Synthesis? On 4/5/15 3:11 PM, Didier Dambrin wrote: I've created plucked strings using additive (not FFT), and it sounds the same as a Karplus Strong, but with more control. So it's definitely doable. The key is: all oscillators have to be phase-unrelated, or it won't sound metallic. are the oscillators harmonic? or not quite harmonic? if the former, do the relative phases change while the note evolves? -- r b-j r...@audioimagination.com Imagination is more important than knowledge. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
On 4/5/15 2:45 PM, Alan Wolfe wrote: Interesting, thanks for the info! What is the usual technique for simulating plucked strings? (: i dunno what is the most common (probably sample playback), but lately Physical Modeling seems to be the craze. Karplus-Strong is another method that appears to me to be closely related. in my opinion, if the overtones are decently close to harmonic, you can use wavetable synthesis for any musical tone. the plucked attack can be a one-shot sample playback and an evolving wavetable synthesis for the entire note after the attack. for harmonic synthesis, wavetable is cheap (i mean efficient) and just as good as additive. there are even ways to slightly detune overtones from their harmonic frequencies and to morph from one tone to another. -- r b-j r...@audioimagination.com Imagination is more important than knowledge. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
On 4/5/15 2:51 PM, Zhiguang Zhang wrote: Plucked strings can be done using the Karplus Strong algorithm, which uses a noise excitation put through a comb filter, or something similar. it's the kind of comb filter with feedback. and you need fractional-sample precision delay before feedback. and the noise excitation is done by preloading the entire delay with random numbers. -- r b-j r...@audioimagination.com Imagination is more important than knowledge. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
I've created plucked strings using additive (not FFT), and it sounds the same as a Karplus Strong, but with more control. So it's definitely doable. The key is: all oscillators have to be phase-unrelated, or it won't sound metallic. -Message d'origine- From: Zhiguang Zhang Sent: Sunday, April 05, 2015 8:51 PM To: A discussion list for music-related DSP Subject: Re: [music-dsp] Uses of Fourier Synthesis? Plucked strings can be done using the Karplus Strong algorithm, which uses a noise excitation put through a comb filter, or something similar. On Sun, Apr 5, 2015 at 2:46 PM, Alan Wolfe alan.wo...@gmail.com wrote: Interesting, thanks for the info! What is the usual technique for simulating plucked strings? (: On Apr 5, 2015 10:36 AM, Peter S peter.schoffhau...@gmail.com wrote: On 05/04/2015, Alan Wolfe alan.wo...@gmail.com wrote: I was wondering, does anyone know of any practical or interesting uses cases of Fourier synthesis for audio? You can use it for additive synthesis and spectral oscillators. I can already make bandlimited square, saw and triangle waves but was hoping for something like guitar strings or voice, or something along those lines. You can create vocoder type sounds using Fourier synthesis (assuming that's what you meant by 'voice'). For guitar strings - I wouldn't use that approach (though you might come up with some convoluted time-varying formula that sounds simlar to some plucked string, but that's not typically how plucked sounds are created). Someone shared photosounder with me, which treats pictures as a spectrogram and lets you hear the images. https://www.youtube.com/watch?v=W8MCAXhEsy4 That's pretty interesting, but anyone else know of any other practical or interesting audio use cases? Spectral morphing? -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp - Aucun virus trouve dans ce message. Analyse effectuee par AVG - www.avg.fr Version: 2015.0.5863 / Base de donnees virale: 4321/9462 - Date: 05/04/2015 -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
On 05/04/2015, robert bristow-johnson r...@audioimagination.com wrote: What is the usual technique for simulating plucked strings? (: i dunno what is the most common (probably sample playback), but lately Physical Modeling seems to be the craze. Karplus-Strong is another method that appears to me to be closely related. Digital waveguide models are also related: https://ccrma.stanford.edu/~jos/pasp/Digital_Waveguide_Models.html -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
On 05/04/2015 17:53, Alan Wolfe wrote: Hey Guys, I was wondering, does anyone know of any practical or interesting uses cases of Fourier synthesis for audio? I can already make bandlimited square, saw and triangle waves but was hoping for something like guitar strings or voice, or something along those lines. In a way, virtually all synthesis is Fourier Synthesis; the problem with literal additive synthesis is that it is (in most cases) extremely computationally expensive, with all of N hundred partials having in principle individual time-value envelopes. All other techniques are efficient but in some way compromised substitutes. In theory, even noise can be rendered additively, but in theory you need an infinite number of oscillators to achieve it. The issue as ever is ease of technical and musical control. Nobody really wants to compute time/value envelopes for 500 oscillators by hand. The more variables there are, the more difficult the control. The great virtue of (analogue) subtractive synthesis is that it is (relatively) easy to implement in electronics, and (relatively) easy to control - choose the waveform and the filter, edit a couple of simple ADSR envelopes, and you are done; then bung the whole lot through a chorus and reverb! The difficulty of creating inharmonic timbres was the great compromise there. Hence tricks such as oscillator sync, ring modulation, n'stuff. One can present a similar story for FM. Nevertheless, check out for example IRCAM's papers on FFT-1, where they use the inverse FFT to synthesise arbitrary partials, each represented by something like 9 FFT bins. When I was working on the sliding phase vocoder using the sliding DFT (frame updated every sample), targetting massively parallel computing hardware (Clearspeed cards, GPUs), all the resynthesis was by oscillator bank; so all partials could be freely modulated in frequency and amplitude. This is available in Csound as a special adaptation of the usual hopping streaming phase vocoder. The same issues of data management and control arise, of course! Richard Dobson -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
Re: [music-dsp] Uses of Fourier Synthesis?
On 4/5/15 3:11 PM, Didier Dambrin wrote: I've created plucked strings using additive (not FFT), and it sounds the same as a Karplus Strong, but with more control. So it's definitely doable. The key is: all oscillators have to be phase-unrelated, or it won't sound metallic. are the oscillators harmonic? or not quite harmonic? if the former, do the relative phases change while the note evolves? -- r b-j r...@audioimagination.com Imagination is more important than knowledge. -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
