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This is a posting of Jim Coker <jcoker@interaccess.com> in '97. I just stumbeled over it and liked it and since we had talk about this going, I repost it. >> Jim answered me: >> >In reference to Matthias' questions, most parameters on sound >> >objects (such as delay times, frequency settings, filter bandwidth >> >and frequency) are controllable in real time, and without glitches. >> >Put an lfo on a short delay, and you get a flanger. (Delay lengths can >> >be specified in a number of ways, such as in seconds, or samples, >> >or relative to something else) Control signals can come from midi, >> >or all sorts of other things, frequency trackers, envelope followers, >> >other audio signals, or signals built by processing other signals. >> >When I was there, a Peavey PC1600 fader box (16 programmable >> >midi faders and assorted buttons) was set up to >> >control sound parameters. This is what I used during the looping >> >test (no foot controller available). >> >> I see... but this I can do on my PCM80, as long as its just controlling >> parameters of a delay. >> I was thinking about the loop specific functions like Tap, Multiply, >Undo, >> or rather sampler type functions like restarting the actual loop or >> changing to another loop and so on. Probably those functions will have >to >> be created and I wondered how difficult this might be. > >Well, there's no tap tempo control that comes with the unit (I asked), >but >I don't think it would be difficult to build one. As far as the >echoplex-type >functions go, it depends on your goal. If you want to duplicate the >interface >of an echoplex, you can probably do it, but I can't say how difficult it >would >be, and I don't think it would be the best way to approach loop >programming >with Kyma. Since you can have a large number of loops and samplers >running >at once, and there are numerous controls available on them, some of the >metaphors >that apply with the echoplex don't make much sense. For example, >multiply >on the echoplex affects the original loop, whereas on Kyma, I would be >more >likely to achive a similar result by adding a new, concurrent loop whose >time is a multiple of the first. This would leave the original loop >available >for individual processing. Of course, everyone has their own preference >about >how such features should be configured, but a big part of Kyma is that >the >user has many options on how to organize things. > >> >> >Another nice patch involved a "harmonic resonator", a special >> >kind of filter that resonates at a given pitch and all it's >> >harmonics. >> >> also available on PCM70/80 >> >> >Probably the most unique capabilities of the system revolve around >> >it's analysis and resynthesis capabilities. Their latest software >> >version comes w/ a configureable vocoder w/ up to 70 filter bands. >> >In addition to real time vocoding, you can analyize a sample >> >(drums, vocals and animal sounds work best, due to their widely >> >varying formants) to build a time-varying filter bank, and then use >> >this filter bank to process a live signal. >> ... >> >> >For really hard-core stuff, you can use an FFT analysis to convert >> >the signal from the time domain into the freqency domain, and do >> >processing there (such as stretching or scaling harmonics, pitch >> >and time shifting, etc), and then resynthesize the result using >> >an oscillator bank. This is the approach used by Digital Performer >> >1.7 and others to do pitch shifting w/o ugly artifacts. Kyma >> >can do this in real time, minus a 1/4sec delay due to FFT >> >windowing issues >> >> Interesting. This could certainly be used to colour and modulate loops. >And >> in this case, the 250ms delay (thats a lot!) could be hidden somehow. > >The delay is intrinsic to all FFT algorithms. The processing occurs by >taking short samples (called windows) of the input, and doing the FFT >on each window. Longer windows give more accurate frequency results, >shorter ones give a better indication of when events occur in the >signal. >The windowing is what causes the delay. I do think it is adjustable, so >shorter delays can be traded for some accuracy. >(caveat: That's a very short and imprecise description of a complex >signal processing task) > > >> >The only dissapointment I had was with the frequency tracker. >> >It works amazingly well w/ vocals, but didn't do so great on >> >a guitar. The response time was at least as good as a Roland >> >GI-10 midi converter and it did track vibrato and >> ... >> > One big change that would make >> >it better would be to use hexaphonic input a-la GK2, which would >> >restrict the pitch guessing range, and avoid multi-string noises. >> >> Did you play monophonic for this test, or is it even able to detect >chords >> of a monophonic guitar?!? > >The tracker can't handle chords, that is truly a difficult task. It is >discussed in the Curtis Roads book I mentioned earlier (as is the FFT >stuff). > >> >> >Currently Kyma only has 2 inputs and 2 outputs, but they are working >> >on increasing this. They get many requests to increase the >> >number of outputs, but Kurt said that this was the first time they >> >had a solid reason for having multiple inputs, ... >> >> Ahh... we will end up making our own VGx, more serious, with all in it! >> >> >Kyma can run simutaneously w/ a >> >sequencer or MAX on a modest MAC or PC. Symbolic Sound is also >> >working on a PC-card interface so you can use Kyma w/ a laptop. >> >> Does it also work without any computer, on stage? > >Nope, the computer is the controller, where all patches are stored and >other important things happen. It also, obviously, lowers the price of >the >Capybara, which has no front panel controls. There is a midi-map >function >so you can use program changes to load new sounds. > >The "stuck-to-a-computer" issue is one the Sym. Sound is aware of. They >had said that at AES some engineers from Eventide had asked if they'd >had people complain about requiring the computer. They are working on a >PC card for laptops, so that makes it a bit less of a problem. The way >I see it is that they leverage so many capabilities from the computer >that >the restriction is well-justified. > >> Did you check the reverb sounds? If the KYMA replaces two Plexes and my >two >> Lexicons, its not that expensive any more! > >I don't know of any serious reverb programs that come with the unit, but >it has Delays, Comb Filters and such that can be used to build reverbs. >There are some general reverb algorithms covered in signal processing >publications, but if you're looking to replace the reverb in a PCM80, >its not gonna happen easily. > >This brings up the issue of what Kyma is all about. The fx boxes from >Lexicon, >Eventide and others come with great programs that are ready-to-use >and are targeted for music production, but even though they have >relatively >flexible programming options, their limitations are rigid: They have a >fixed >processing & memory capacity (for both delays and programs), a limited >number of processing algorithms (i.e. chorus, flange, pitch shift, >reverb), and limited >number of ways to combine those algorithms. Kyma is an open-ended box, >it is >what the user makes of it. Symbolic Sound provides a number of useful >processing algorithms, software to combine them in new and interesting >ways, many intriguing >and instructive example programs, and ongoing software and hardware >updates that avoid obsolecence. > >It blurs the distinction between synthesizer, effects processor, hard >disk >recorder, sampler and sequencer. It is a little bit of all these >things, but >by combining them all it becomes something different entirely. The >first >demonstration Carla showed me was a piece that she had created for Kyma. >The complex >program turned the Capybara into an instrument, in that it created >synthesized >sounds, an effects processor, in that it processed her voice in real >time, a >sampler, as it played & modified sounds from disk, a sequencer, in that >sounds >were layered and ordered by program events, and a real-time studio or >composition tool, in that the operation of all these processes were >interrelated, >and she was able to control the whole process through vocal inflections >and >midi sliders. > >Kyma is a solution for those who have >become frustrated with the limitations of the equipment >they are working with, and want to create an instrument of their own. It >will not >likely replace a Lexicon reverb unit in anyone's rack, but reveberant >sounds >built using it can be new and unique. It may not harmonize as >effortlessly as >an Eventide, but it has numerous tools for modifying pitch. It is a >toolset >for creating music, and thus the user has both the exciting and >somewhat daunting task of making something out of it. > > > >jim * Lots of music (samples), inventions (drawings), philosophy: * ---> http://Matthias.Grob.org * Archive and mailinglist about looping: * ---> http://www.annihilist.com/loop/loop.html