Hi the papers on http://www.klippel.de/pubs/papers.asp where quiet interesting. But the page went down. It looks like it went to: http://www.klippel.de/nc/know-how/literature/papers.html?sword_list[0]=paper&sword_list[1]=speaker
Greetings Am 16.10.2010 06:46, schrieb Martin Schied: > Hi! > > I'm no speaker modeling expert at all, but I can try to describe what > produces sounds in an overloaded speaker. There are various sources of > distortion, symmetrical (mechanic suspension) and asymmetrical > (magnetic field) and also time variant (temperature) and modulation > (doppler effect / amplitude modulation) effects. I don't know which > effects have a stronger or weaker influence, but I describe what I > imagine: > > > High peak amplitude, positive wave: > > speaker moves to the front, parts of the coil will not be in the > magnetic field anymore. The field isn't zero outside the magnet gap, > but I guess it decreases rapidly and is almost zero (so for example if > half the coil is inside the magnet, the parts outside will not produce > a force. So the force is only half as strong as it should. For > simplicity you could say the field outside the magnet's gap is zero, > so you have a linear function of excitation / current. Also If the > coil moves out of the field its impedance will decrease which has > influence on frequency response for higher frequencies a bit. > > Heat > > If the impedance is reduced as described above, a higher current will > flow and heat the coil more than usual. The resistance of the coil > will increase when it gets warmed and thus the efficiency of the > speaker decreases (up to -7 dB I read somewhere, but this wasn't meant > for almost dead speakers but heavy load). The heat needs some time to > dissipate, so some kind of slow pumping compression effect occurs. > > High amplitude, negative wave: > > The speaker's coil might crash into the magnet and create different > mechanical noises. Also the speakers diaphragm will be deformed by > this crash and create various kinds of noise. Additionally it carries > the noises the coil created - depending on the material and shape this > sound different (paper, Kevlar, aluminum, etc sound different). If > this crash doesn't occur (professional speakers don't have this issue > usually) the negative wave will not be distorted too much and maybe > distortion can be ignored. > > In both directions the spider (basically a spring) starts to become > nonlinear. Different manufacturers have different curves, but for > small amplitudes they all pretend to be linear - so some experiments > with sin~ or tanh~ might do it here. > > Then generally there are happening doppler-effects on all speakers > with big excursion. You could model them through a variable delay, > modulated by a differentiated, low pass filtered signal (don't bite if > I'm wrong, it's already very late... ). Amplitude modulation can be > applied the same way (lowpass and apply it to higher frequencies). > > so to sum it up: > > apply symmetric distortion for the spider, split the path into > positive and negative parts, for positive samples: tanh~, polynomials > or other wave shapers, for negative parts let the signal untouched or > add noises of a crashing coil (don't know how to achieve this), then > sum both signals up, apply doppler effect, amplitude modulation and > pumping compression. perhaps that sounds like your speakers then :) > > I'm not sure if this works at all, but it definitely will sound very > distorted in the end. > > did you already discover http://www.klippel.de/pubs/papers.asp ? > > > > cheers > Martin > > > On 15.10.2010 21:10, - wrote: >> Thank you for your answer, >> but as I wrote I don't want the sound of simple clipping like clip~, >> tanh~ or overdrive~. I want the sound of a speaker crying for mercy >> because you put just too much through it. >> >> But I don't know where to start. I know there are complex distortion >> effects, which are able to simulate different speaker cabinets after >> variable amps recorded by different microphones. But they all cost big >> money. Also I don't need the physical simulation. I just want the sound. >> If you want I can try to record the sound I'm talking about. >> >> I tried to search for information how to do this but couldn't find >> anything usable. Not even an analysis what happens inside the speaker >> when you torture it like this. >> >> I already know the forum but don't want to doublepost. I really liked >> the post about the oto biscuit. Neat distortion possibility's. >> >> >> Am 15.10.2010 17:12, schrieb George Ker: >> >>> Hello, >>> I can't really understand, so , you mean something different from >>> >> [clip~] ? >> >>> I' m sure you can find really good patches in the puredata.hurleur.com >>> >> forum searching about distortion , overdrive clip etc >> >>> ----- >>> >>> GeorgeKer~ >>> >>> http://tinyurl.com/georgeker >>> >>> ----- >>> >>> >>> >>> On 14 October 2010 23:19, - <[email protected]> >>> <mailto:[email protected]> wrote: >>> >>> Hi, >>> >>> does anyone know how to simulate the sound of an overdriven >>> >> speaker? You >> >>> know the crunchy sound when you torture it with a strong bass. It's >>> nowhere near the sound of an normal overdrive with some kind of >>> >> clipping. >> >>> Greetings >>> - >>> >>> _______________________________________________ >>> [email protected] <mailto:[email protected]> mailing list >>> UNSUBSCRIBE and account-management -> >>> >> http://lists.puredata.info/listinfo/pd-list >> >>> >> _______________________________________________ >> [email protected] <mailto:[email protected]> mailing list >> UNSUBSCRIBE and account-management -> >> http://lists.puredata.info/listinfo/pd-list >> >> >
_______________________________________________ [email protected] mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
