ciao,
provo a risponderti io. Sono sì un hammondista ma non sono un tecnico, quindi devo riferire cose scritte da altri. Il keyclick è stato uno degli insuccessi di maggior successo... una caratteristica ineliminabile e non voluta dell'hammond, è diventato un must per chi produce cloni. Stano destino dei cloni. Hai la tecnologia per migliorare/eliminare i difetti dell'epoca, e invece ti devi scervellare per riprodurli, e anche bene, per giunta!
Alcuni cloni non ti fanno intervenire sul timbro del click, ma solo sul volume e sulla durata, oltre che alla risposta alla velocity. Ecco, io quando trovo questi parametri mi intimidisco, preferisco che non si possa modificare nulla o quasi, tanto difficilmente io riuscirei a fare di meglio...
Probabilmente, comunque, il keyclick non era un rumore costante, probabilmente variava a seconda dell'età dell'organo; quello che ti posso consigliare è avere sottomano un qualche altro clone (anche l'electro del 3d), mettere a manetta il click, tirare solo un drawbar, e cercare il suono di click che più si avvicina.
Per quanto riguarda cos'è il click, ti incollo questa interessante disamina:
[c]It's commonly assumed that the keyclick is caused by bouncing switch contacts and the fact that all nine switches under a key don't make contact simultaneously. Although some of the keyclick is undoubtedly caused by that, I've come to the conclusion that this is not the main source.
Instead, the click is caused by bad timing. Consider that the tonewheel generator is creating (near-)sine waves all the time. When you press a single key with a single drawbar pulled out, one sine wave will be sent to the amplifier. At the moment that you press the key, the sine wave coming out of the tone generator could be at any point in its cycle. If it happened to be at one of its zero-crossings, there would be no keyclick, since at that instance, the wave is at the same voltage as the busbar (zero).
However, if the wave is at a high or low point, or somewhere in between, then the busbar will jump suddenly (theoretically instantaneously) from 0mV to whatever the instantaneous voltage of the wave happens to be (e.g. 15mV). Effectively, the tone starts out as a square wave for the first part of the cycle, which is rich in odd harmonics. Press several keys at once with several drawbars pulled out, and you're going to get a lot of noise for that instant.
Hammond tried to reduce the keyclick by putting a first order (6dB/octave) low-pass filter in the preamp to attenuate the higher harmonics. Since this had to work even for low notes, where the 3rd, 5th, etc. harmonics are actually lower in frequency than the fundamental of many of the higher notes, the filter had to have a quite low cut-off frequency, which would dull the higher notes. Hammond got around this by increasing the output of the higher tone generators to compensate for the loss of high frequency response.
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