Page 1 of 1

YM2612 digital sound

Posted: Mon Dec 17, 2007 11:17 pm
by Shiru
I wonder if anybody tried to use channels 1-5 or 6 in normal mode as DACs, by changing TL of slots (something like playing digital sound on PSG)? According to TmEE it's possible to output register data with fixed delay, and this delay seems smaller than needed to reach acceptable samplerate. If that possible, it can be useful for something like MOD-player with better qualtity than possible with channel 6 DAC.

And some OT. There is already many threads about YM2612 and sound, maybe it's time to make related subforum?

Re: YM2612 digital sound

Posted: Tue Dec 18, 2007 12:36 am
by Chilly Willy
Shiru wrote:I wonder if anybody tried to use channels 1-5 or 6 in normal mode as DACs, by changing TL of slots (something like playing digital sound on PSG)? According to TmEE it's possible to output register data with fixed delay, and this delay seems smaller than needed to reach acceptable samplerate. If that possible, it can be useful for something like MOD-player with better qualtity than possible with channel 6 DAC.

And some OT. There is already many threads about YM2612 and sound, maybe it's time to make related subforum?
Funny, I had the same thought some time ago. Put the channel into algo 7 and you have four DACs usable through changing the TL per channel. Just haven't had the chance to play around with that yet. The main limitation I can see is that TL is log, not linear. So you don't get the same resolution - it's log2(width of TL) instead of (width of TL). Still, it could be very useful.

Posted: Tue Dec 18, 2007 6:24 am
by TmEE co.(TM)
On another FM synth forum (http://www.soundshock.se), someone mentoined this way... I don't know the details how can you make sound like so (make operator output constant tone or something and adjust TL ?)...
Why did Yamaha go with logarithmic levels ? It gives me lots of headache in my sound system !!!

Posted: Tue Dec 18, 2007 1:25 pm
by Chilly Willy
TmEE co.(TM) wrote:On another FM synth forum (http://www.soundshock.se), someone mentoined this way... I don't know the details how can you make sound like so (make operator output constant tone or something and adjust TL ?)...
Why did Yamaha go with logarithmic levels ? It gives me lots of headache in my sound system !!!
If the sound was high enough frequency, it would be the same as low-passed filtered amplitude modulation. I don't know if you could set the frequency high enough for that, though. The other idea is to go with a super low frequency with the largest rate delay possible.

As to log levels, that's easy. Most physical processes are logarithmic in nature. Hearing, for example. Both tones and volume are logarithmic in response, so making the volume logarithmic makes the perception linear. With log volume, setting the volume to half full scale actually makes the volume sound half as loud. So log volume makes perfect sense. But it does make digital output via the volume a pain.

Posted: Tue Dec 18, 2007 5:18 pm
by TmEE co.(TM)
I hate logarithmic... especially on my amp where sound is quiet-quiet-quiet-quiet-loud-REALLY loud... and in my sound engine I get hard time too, since MIDI volume levels are linear (Tracker works on MIDI) and on MD things sound too different.