Archive of the former Yahoo!Groups mailing list: Yamaha CS80

Hi all
One of the things I always believed that showed the magic of CS synthesizers was the ringmodulator, the richest I ever heard . If anyone thought that this magic was in the ringmodulator itself , well , the multiplier circuit is nothing special really....what I discovered on the other hand is that the waveform used as the modulator is very special : the sine that was outputted by the iG00150 LFO was indeed a "wrong" sine : I mean it is not pure, and when I say this I mean it has some harmonics that contribute to enforce the fundamental and enrich the modulation therefore; thanks to a sample that Georges Poropat provided me with I made a FFT analysis of this wave and I found that there are 9 more significative harmonics that influence the waveform, each set to different amplitudes and mostly of the odd type; moreover there is a phase difference between each harmonic that provides a noisy high end and gives another particular flavour to the sound; the audio result is that , even with low frequencies the modulation sounds very rich, in fact the full speed without modulation doesn't go beyond 220Hz and the full modulation with the envelope goes no further than 2500Hz...what amazed me is that I was able to synthesize this wave by layering these 9 sines at their respective amplitudes not forgetting to to give a compensation in amplitudes related with the "expression circuit" lowpass filters' influence ( 6dB/Oct at 1KHz, but I'm speculating there ). The result of modulating waves with this special sine is 99% faithful to the original...if anyone would like to hear this experiments I can post them on the site.
Max

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