Example: very grainy sound

jorge · 17 Oct 2004

Hi lalo,

After version d was released I also noticed the grainy nature in the lower notes although I didnt investigate yet what causes it. To be honest, the schematic examples we release are done very quickly as we're normally busy with coding. If you ever create a good Example schematic candidate that you'd let us include in a release it would be great. The current ( version 0.9.0d ) example schematic mutliplies two sawtooth waves which normally needs twice the existing bandwidth and consequently causes aliasing. That's the reason why I filtered both sawtooths first but I didnt use any scientific calculations. Maybe with the lower notes, the ADSR causes the cutoff of the sawtooths to move too high which due to the doubling of bandwidth is converted into aliasing.

lalo · 18 Oct 2004

i'll do a test with a plain osc-to filter(with adsr)-to amp (with adsr) so i hope we'll sort it out 😉 ...today i have to do lessons..so i'll do tests tomorrow thanx lalo

lalo · 20 Oct 2004

ok...did a test...to me it's like something strange is goin' on in the filter code.. when resonance is around 7 and more i have nasty distortion ...but my amp stage is at 0.05 so very low...but distortion is there... another issue is that the ADSR is not visually proportinal to time values...in a few pixel it goes to very short values to very long ones.. a grid could be useful thanx lalo

lalo · 21 Oct 2004

?? lalo 🙂 ..ps.. i miss the mirc times 🙂

jorge · 21 Oct 2004

hi lalo

I miss the mirc times too, if I knew when you're there, I'd go there too. Is there any other way we can be in touch? I use MSN messenger and also Skype.

The resonance of the filter causes the gain near cutoff to be much higher than 1 and that's what causes the distortion. Would you prefer to have the maximum response of the filter normalized to 1? I'm not sure if that's a good solution as all the rest of the response would be attenuated.

Having the ADSR response not proportional to time is on purpose as otherwise it is very hard to control short attacks/decay/releases. I like your idea of having a grid. The ADSR component will most probably evolve quite a lot, it will probably be made from low-level primitives allowing many parameters and functionality to be changed.

lalo · 21 Oct 2004

hi jorge! ...downloading skype...how can i contact you through that app?

the filter...

well all we need is to know how values are mapped in your code 😉 and to have a filter capable of selfoscillation without distorting...

the ADSR..

well ..time is linear so a direct visual proportion could be better..but is just my opinion...the adsr just need a Zoom...btw i think that the way that module is done is quite non-SM 😉.....i'd prefer to have the GUI not linked to the functionalities..i'd do my gui with primiyives...well cbit would do it 😉

thanx lalo

jorge · 21 Oct 2004

you can contact me on skype using my username [contact removed] that's "jorge" followed by two "_"