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2002-08-22 by sealed
Hello, I made up a page on CASIO HZ/HT with some sampled sounds from HT-3000. http://homepage.mac.com/synth_seal/html/ht3000.html Having investigated a bit more, I came to the conclusion that it might not be PD synth, but what I call additive square wave synth. But its sound still resembles CZ... If you are interested, please drop in and if you have something to tell about HZ/HT, please let me know. Best wishes, Sealed
2002-08-22 by Furman, Jon W.
Very cool page. Thanks sealed. Very very interesting stuff.
-----Original Message----- From: sealed [mailto:sealed@...] Sent: Thursday, August 22, 2002 10:21 AM To: CZsynth@yahoogroups.com Subject: [CZsynth] New HZ/HT page Hello, I made up a page on CASIO HZ/HT with some sampled sounds from HT-3000. http://homepage.mac.com/synth_seal/html/ht3000.html <http://homepage.mac.com/synth_seal/html/ht3000.html> Having investigated a bit more, I came to the conclusion that it might not be PD synth, but what I call additive square wave synth. But its sound still resembles CZ... If you are interested, please drop in and if you have something to tell about HZ/HT, please let me know. Best wishes, Sealed To unsubscribe from this group, send an email to: CZsynth-unsubscribe@yahoogroups.com Your use of Yahoo! Groups is subject to the Yahoo! <http://docs.yahoo.com/info/terms/> Terms of Service. [Non-text portions of this message have been removed]
2002-08-22 by Scott Nordlund
>Having investigated a bit more, I came to the conclusion that it might >not be PD synth, but what I call additive square wave synth. I wouldn't really think that it's an "additive square wave" synth. The Poly 800 was a bit of a special case. I'm pretty sure it used a sound chip intended for arcade games. I think the Siel DK 70 and DK 80 used the same chip. Anyway the trick with the 800 is that if you had the waveform on square, all the different wave footages that were turned on would have the same amplitude, and if the saw wave was selected, the different footages would have different amplitudes so it would approximate a saw wave, much like the sample you've got on the page. You probably knew that already. Anyway what I'm getting at is while that arrangement could make the saw wave, it couldn't make most other waves without being able to adjust the phase and pulsewidth of each square wave independently. Think about how you would go about making a triangle wave out of just squares- one square wave to get the basic shape of it, then add 2 different pulse waves, one 25% duty with a 90 degree phase shift, and one 75% duty with a 270 degree phase shift (I think..) then more to refine it further. I worked it out on paper but I'm not really sure if I got that right or not. At any rate what I'm getting at is that it would be very difficult to get most waves this way. Seeing as how it has 16 steps, the saw wave looks more like it comes out of a 4-bit DAC. To me this would seem pretty likely. It still doesn't explain how the waveforms are made, and particularly why they're affected by the amplitude envelope, but it makes some sense... I could look at the waves on my computer and try to get a better idea of what's going on... _________________________________________________________________ Join the world\ufffds largest e-mail service with MSN Hotmail. http://www.hotmail.com
2002-08-23 by sealed
> I wouldn't really think that it's an "additive square wave" synth. The Poly > 800 was a bit of a special case. I'm pretty sure it used a sound chip > intended for arcade games. I think the Siel DK 70 and DK 80 used the same > chip. For your interest, Poly-800 uses KORG MSM5232 for DCO, and KORG NJM2069 for VCF and VCA. (See: http://www.asahi-net.or.jp/~wz4k-tnk/semi/poly800.html It is a great site but written in Japanese.) I opened my HT-3000 to compare the chips, and found what I believe to be the main circuit board. Besides the CPU PD78C10 and a memory chip, there was mysterious chips called MSM6294-03 and MSM6294-04, manifactured by OKI semiconductors. The name MSM is used by OKI, so KORG's chips may also be made by OKI. But I found no information on the net about these chips. > Anyway what I'm getting at is while that arrangement could make the saw > wave, it couldn't make most other waves without being able to adjust the > phase and pulsewidth of each square wave independently. Think about how you > would go about making a triangle wave out of just squares- one square wave > to get the basic shape of it, then add 2 different pulse waves, one 25% duty > with a 90 degree phase shift, and one 75% duty with a 270 degree phase shift > (I think..) then more to refine it further. I worked it out on paper but > I'm not really sure if I got that right or not. At any rate what I'm > getting at is that it would be very difficult to get most waves this way. I haven't thought of the possibility of creating triangle wave out of square waves. I don't know much about phase issues. As mp3s on my site shows, HT's DCO can't generate such a soft-sounding wave like triangle. They produce so many variations of pulse and square waves. 'Additive square wave' synths may not be able to control phases and pulse width. I think the pulse widths are fixed to 50%. In fact, Poly-800 has no Pulse width parameters. Poly-800's DCO and Roland's sub-oscillators generate square waves by 'dividing' the master clock. So, the phases of each harmonics are always synced, I think. > Seeing as how it has 16 steps, the saw wave looks more like it comes out of > a 4-bit DAC. To me this would seem pretty likely. It still doesn't explain > how the waveforms are made, and particularly why they're affected by the > amplitude envelope, but it makes some sense... Yes, it may be. (Inspired by your comment, I thought that Poly-800 could be called a 4-bit synth.) When I first saw the waveform displayed, I thought my HT might be a 4- bit PD synth. But after a while, I came to think that PD needs at least 8-bit DAC or so. So I'm confused again as to its synthesis engine... I'm still rather for my 'additive square' hypothesis, but I'm not so certain about whether my HT has a ring modulator... > I could look at the waves on my computer and try to get a better idea of > what's going on... Further comments appreciated. Best, Sealed
2002-08-23 by sealed
Thank you very much for your response! This is my first web page, and I'm glad and appreciate your comments. I rewrote a bit some clumsy description about DCO, but it may not still be so clear as some aspects of SD synthesis remains mysterious... Best, Sealed > Very cool page. Thanks sealed. Very very interesting stuff. > > > > -----Original Message----- > From: sealed [mailto:sealed@...] > Sent: Thursday, August 22, 2002 10:21 AM > To: CZsynth@yahoogroups.com > Subject: [CZsynth] New HZ/HT page > > > > Hello, > > I made up a page on CASIO HZ/HT with some sampled sounds from HT-3000. > > http://homepage.mac.com/synth_seal/html/ht3000.html > <http://homepage.mac.com/synth_seal/html/ht3000.html> > > Having investigated a bit more, I came to the conclusion that it might > not be PD synth, but what I call additive square wave synth. > > But its sound still resembles CZ... > > If you are interested, please drop in and if you have something to tell > about HZ/HT, please let me know. > > Best wishes, > Sealed > > > To unsubscribe from this group, send an email to: > CZsynth-unsubscribe@yahoogroups.com > > > > Your use of Yahoo! Groups is subject to the Yahoo! > <http://docs.yahoo.com/info/terms/> Terms of Service. > > > > [Non-text portions of this message have been removed] > > > ------------------------ Yahoo! Groups Sponsor --------------------- ~--> > 4 DVDs Free +s&p Join Now > http://us.click.yahoo.com/pt6YBB/NXiEAA/mG3HAA/QnLolB/TM > --------------------------------------------------------------------- ~-> > > To unsubscribe from this group, send an email to: > CZsynth-unsubscribe@yahoogroups.com > > > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/ terms/ > >
2002-08-23 by Furman, Jon W.
I listened to your HT sound samples last night and just from the sound of them I'd have to say that they sounded a lot like the sound set on my old Casio MT-68, which must have been form the early or mid 80's. I think that that keyboard used some kind of hard wired analog algorithms to do it's thing and also had a line select feature. Come to think of it the MT-68 was an odd little beast also. Very nasty sounding but also kind of cool. Jon [Non-text portions of this message have been removed]
2002-08-23 by sealed
Before PCM ruled the world, many cheap keyboards were actually analog. I hear some CASIO MT series used SD synthesis like HZ/HT. Maybe, HZ/HT are versions of Casiotones with extended ability to edit its sound. I don't know what H means, but T of HT might represent casioTone. And you say MT-68 is editable, and I suppose it should be great. Yes, nasty and cool, and it may generate quite similar sounds as HZ/HT. 'Line select' attracts me much. What kind of function is it? Around that time, sound editing capability was much favored. CASIO and YAMAHA produced some editable pop keyboards (Notably, some YAMAHAs can be edited via MIDI). Good old days for synths... Sealed > I listened to your HT sound samples last night and just from the sound of > them I'd have to say that they sounded a lot like the sound set on my old > Casio MT-68, which must have been form the early or mid 80's. I think that > that keyboard used some kind of hard wired analog algorithms to do it's > thing and also had a line select feature. Come to think of it the MT- 68 was
> an odd little beast also. Very nasty sounding but also kind of cool. > > > > Jon
2002-08-23 by Furman, Jon W.
I'm 100% sure that the MT is not PCM, it just sounds too bad! The MT-68 is not really editable but each sound may be set at one of three different envelope settings. The first setting is just the preset setting which makes the tones sound like bad emulations of real instruments and the other two settings seem to introduce weird envelopes to the filter and amp circuits. Usually line select settings 2 and 3 are next to useless musically but are good for some weirdo type sounds. I always secretly liked the rhythm section though, I always thought that it would be cool to MIDI it up somehow......
-----Original Message----- From: sealed [mailto:sealed@...] Sent: Friday, August 23, 2002 2:34 PM To: CZsynth@yahoogroups.com Subject: RE: [CZsynth] New HZ/HT page Before PCM ruled the world, many cheap keyboards were actually analog. I hear some CASIO MT series used SD synthesis like HZ/HT. Maybe, HZ/HT are versions of Casiotones with extended ability to edit its sound. I don't know what H means, but T of HT might represent casioTone. And you say MT-68 is editable, and I suppose it should be great. Yes, nasty and cool, and it may generate quite similar sounds as HZ/HT. 'Line select' attracts me much. What kind of function is it? Around that time, sound editing capability was much favored. CASIO and YAMAHA produced some editable pop keyboards (Notably, some YAMAHAs can be edited via MIDI). Good old days for synths... Sealed > I listened to your HT sound samples last night and just from the sound of > them I'd have to say that they sounded a lot like the sound set on my old > Casio MT-68, which must have been form the early or mid 80's. I think that > that keyboard used some kind of hard wired analog algorithms to do it's > thing and also had a line select feature. Come to think of it the MT- 68 was > an odd little beast also. Very nasty sounding but also kind of cool. > > > > Jon Yahoo! Groups Sponsor ADVERTISEMENT <http://rd.yahoo.com/M=228862.2128520.3581629.2204139/D=egroupweb/S=17050321 44:HM/A=1182708/R=0/*http:/adfarm.mediaplex.com/ad/ck/990-1736-1039-333%0d%0 a> To unsubscribe from this group, send an email to: CZsynth-unsubscribe@yahoogroups.com Your use of Yahoo! Groups is subject to the Yahoo! <http://docs.yahoo.com/info/terms/> Terms of Service. [Non-text portions of this message have been removed]
2002-08-23 by Scott Nordlund
>And you say MT-68 is editable, and I suppose it should be great. Yes, >nasty and cool, and it may generate quite similar sounds as HZ/HT. >'Line select' attracts me much. What kind of function is it? I think the pre-PCM Casios used a sort of analog/digital approach. In my PT-80 I think the way it works is a few basic enveloped waves come off of the main chip (drum sounds included) and they are processed a bit on another board with simple fixed filters and things like that to get the different sounds. I don't know what the specific circuits do but I have the general idea. But the PT-80 was monophonic. As far as I know all of the PTs and VLs and low end things like that worked the same way. I don't know about the MTs but I would imagine they're similar. >Around that time, sound editing capability was much favored. CASIO and >YAMAHA produced some editable pop keyboards (Notably, some YAMAHAs can >be edited via MIDI). Good old days for synths... In addition to an HT-700 (and MT-68 as well!) I've been meaning to look for a Yamaha PSS-470 or something like that. Great OPL-style FM. the 680 is even better.... _________________________________________________________________ Send and receive Hotmail on your mobile device: http://mobile.msn.com
2002-08-23 by Scott Nordlund
>For your interest, Poly-800 uses KORG MSM5232 for DCO, and KORG NJM2069 for VCF and VCA. >(See: http://www.asahi-net.or.jp/~wz4k-tnk/semi/poly800.html >It is a great site but written in Japanese.) right. I think that page is where I initially got the info. A search for MSM5232 will give you a lot of arcade game pages... And not that it has anything to do with anything but the 2069 filter chip has a beautiful sound and was also used in the DW-8000 and DSS-1. >I opened my HT-3000 to compare the chips, and found what I believe to >be the main circuit board. Besides the CPU PD78C10 and a memory chip, >there was mysterious chips called MSM6294-03 and MSM6294-04, manifactured >by OKI semiconductors. The name MSM is used by OKI, so KORG's chips may >also be made by OKI. But I found no information on the net about these chips. Interesting that you mention the PD78C10, because my VZ-10M uses a PD78C14, both NEC processors in the same family...but I have no idea what the MSM chips would be... Let's see...to get really speculative, the custom chips in the VZ-10M were made by Hitachi, and I think I've noticed some other brands in other casios, but never a "casio" chip. This would indicate to me that Casio doesn't (or at least didn't at the time) manufacture their own chips...thus the OKI chips are likely custom creations, which unfortunately means that it's the end of the road as far as digging deep into the synthesis methods of the HTs goes (unless you want to try reverse-engineering the whole thing...and I'm sure you have something better to do there...) >I haven't thought of the possibility of creating triangle wave out of >square waves. I don't know much about phase issues. >As mp3s on my site shows, HT's DCO can't generate such a soft-sounding >wave like triangle. They produce so many variations of pulse and square >waves. Well..a 4-bit triangle wave would hardly sound soft. It would have the basic triangle tone but with a lot of high ringy harmonics. The Nintendo (I guess that would be a Famicom to you?) triangle wave was 4-bit and had a very interesting quality to it.. >'Additive square wave' synths may not be able to control phases and pulse >width. I think the pulse widths are fixed to 50%. In fact, Poly-800 has no Pulse width parameters. >Poly-800's DCO and Roland's sub-oscillators generate square waves by >'dividing' the master clock. So, the phases of each harmonics are always >synced, I think. That's what I was getting at. you can't get truly complex waves when they're all phase-synced and fixed pulsewidths. So if you were really determined, you could get a bunch of graph paper or something, look at a good variety of the waveforms and try to recreate them by using octaved, phase synchronized square waves of different amplitudes. This would is probably a lot more effort than it's worth. > Seeing as how it has 16 steps, the saw wave looks more like it comes out of > a 4-bit DAC. To me this would seem pretty likely. It still doesn't explain > how the waveforms are made, and particularly why they're affected by the > amplitude envelope, but it makes some sense... >When I first saw the waveform displayed, I thought my HT might be a 4- >bit PD synth. But after a while, I came to think that PD needs at least >8-bit DAC or so. So I'm confused again as to its synthesis engine... >I'm still rather for my 'additive square' hypothesis, but I'm not so >certain about whether my HT has a ring modulator... I don't know...In theory phase distortion could be 4-bit but it would have too much quantization noise to be useless to all except people like me :) I think one thing you need to do is see for sure what the waveform is doing when it decays...It could be getting distorted slightly by the filter at higher amplitudes but it doesn't look like it when I see the saw wave. Maybe you could cut a bunch of short samples from a long decay, normalize them all and see if they're any different. If it's actually undergoing any sort of meaningful change then it effectively rules out PCM samples (unless they used some sort of wavetable thing like a PPG, in which case it would be quite overcomplicated as well as very poorly implimented...) You might also want to check out the noise source too and try to figure out how that works. _________________________________________________________________ Send and receive Hotmail on your mobile device: http://mobile.msn.com
2002-08-24 by sealed
I looked at Synth Site and found a link to MT-68 demos. http://www.audiva-music.de/casio.shtml (Is he on this list?) I found the music very very amusing to me. Not only being an analog keyboard, its drums also analog! (Further, it may be filtered?) Sorry for being openly excited... (Jon, you liked it secretly...) Some presets may not be good, but the hardware itself seems to be very cool... Analog is what is admired today. CASIO made it very cool, cheap, compact, and especially, in a funny design... Best, Sealed HZ/HT page http://homepage.mac.com/synth_seal/html/ht3000.html > I'm 100% sure that the MT is not PCM, it just sounds too bad! The MT- 68 is > not really editable but each sound may be set at one of three different > envelope settings. The first setting is just the preset setting which makes > the tones sound like bad emulations of real instruments and the other two > settings seem to introduce weird envelopes to the filter and amp circuits. > Usually line select settings 2 and 3 are next to useless musically but are > good for some weirdo type sounds. > > > > I always secretly liked the rhythm section though, I always thought that it > would be cool to MIDI it up somehow...... > > > > -----Original Message----- > From: sealed [mailto:sealed@...] > Sent: Friday, August 23, 2002 2:34 PM > To: CZsynth@yahoogroups.com > Subject: RE: [CZsynth] New HZ/HT page > > > > Before PCM ruled the world, many cheap keyboards were actually analog. > I hear some CASIO MT series used SD synthesis like HZ/HT. Maybe, HZ/ HT > are versions of Casiotones with extended ability to edit its sound. I > don't know what H means, but T of HT might represent casioTone. > > And you say MT-68 is editable, and I suppose it should be great. Yes, > nasty and cool, and it may generate quite similar sounds as HZ/HT. > 'Line select' attracts me much. What kind of function is it? > > Around that time, sound editing capability was much favored. CASIO and > YAMAHA produced some editable pop keyboards (Notably, some YAMAHAs can > be edited via MIDI). Good old days for synths... > > > Sealed > > > > I listened to your HT sound samples last night and just from the sound > of > > them I'd have to say that they sounded a lot like the sound set on > my old > > Casio MT-68, which must have been form the early or mid 80's. I think > that > > that keyboard used some kind of hard wired analog algorithms to do > it's > > thing and also had a line select feature. Come to think of it the MT- > 68 was > > an odd little beast also. Very nasty sounding but also kind of cool. > > > > > > > > Jon > > > > > > > > Yahoo! Groups Sponsor > > > > ADVERTISEMENT > > <http://rd.yahoo.com/M=228862.2128520.3581629.2204139/D=egroupweb/S= 17050321 > 44:HM/A=1182708/R=0/*http:/adfarm.mediaplex.com/ad/ck/990-1736-1039- 333%0d%0 > a> > > > To unsubscribe from this group, send an email to: > CZsynth-unsubscribe@yahoogroups.com > > > > Your use of Yahoo! Groups is subject to the Yahoo! > <http://docs.yahoo.com/info/terms/> Terms of Service. > > > > [Non-text portions of this message have been removed] > > > ------------------------ Yahoo! Groups Sponsor --------------------- ~--> > 4 DVDs Free +s&p Join Now > http://us.click.yahoo.com/pt6YBB/NXiEAA/mG3HAA/QnLolB/TM > --------------------------------------------------------------------- ~-> > > To unsubscribe from this group, send an email to: > CZsynth-unsubscribe@yahoogroups.com > > > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/ terms/ > >
2002-08-24 by sealed
> I think the pre-PCM Casios used a sort of analog/digital approach. In my > PT-80 I think the way it works is a few basic enveloped waves come off of > the main chip (drum sounds included) and they are processed a bit on another > board with simple fixed filters and things like that to get the different > sounds. I don't know what the specific circuits do but I have the general > idea. But the PT-80 was monophonic. As far as I know all of the PTs and > VLs and low end things like that worked the same way. I don't know about > the MTs but I would imagine they're similar. Perhaps they all share similar synth engine. I don't know much about PT... VL is familiar to me through the records of Bill Nelson in the 80's... Earlier models of MT (and PT) seem to have analog drums with analog filter, which is an attractive feature to me. > >Around that time, sound editing capability was much favored. CASIO and > >YAMAHA produced some editable pop keyboards (Notably, some YAMAHAs can > >be edited via MIDI). Good old days for synths... > > In addition to an HT-700 (and MT-68 as well!) I've been meaning to look for > a Yamaha PSS-470 or something like that. Great OPL-style FM. the 680 is > even better.... I recently saw a PSS-470 in an auction in Japanese site. Many people wanted to buy 470 and at last it was sold at $80 or so. I too wanted to get it, but I managed to stop myself, as I've already got TG33, which shares 2 operator FM engine. But MIDIed mini-keys and 680's symphonic effect are also attractive... Best, Sealed HZ/HT page http://homepage.mac.com/synth_seal/html/ht3000.html
2002-08-24 by sealed
> >For your interest, Poly-800 uses KORG MSM5232 for DCO, and KORG NJM2069 > for VCF and VCA. > >(See: http://www.asahi-net.or.jp/~wz4k-tnk/semi/poly800.html > >It is a great site but written in Japanese.) > > right. I think that page is where I initially got the info. A search for > MSM5232 will give you a lot of arcade game pages... I'm surprised you already know the Japanese page! > And not that it has anything to do with anything but the 2069 filter chip > has a beautiful sound and was also used in the DW-8000 and DSS-1. Maybe they have 8 pieces of 2069... > thus the OKI chips are likely custom creations, which unfortunately > means that it's the end of the road as far as digging deep into the > synthesis methods of the HTs goes Yes, maybe. > Well..a 4-bit triangle wave would hardly sound soft. It would have the > basic triangle tone but with a lot of high ringy harmonics. The Nintendo (I > guess that would be a Famicom to you?) triangle wave was 4-bit and had a > very interesting quality to it.. I see! Yes, it is called Famicom. I haven't had it but I agree its sound was unique... not harsh square, nor soft triangle... > I don't know...In theory phase distortion could be 4-bit but it would have > too much quantization noise to be useless to all except people like me :) I > think one thing you need to do is see for sure what the waveform is doing > when it decays...It could be getting distorted slightly by the filter at > higher amplitudes but it doesn't look like it when I see the saw wave. > Maybe you could cut a bunch of short samples from a long decay, normalize > them all and see if they're any different. If it's actually undergoing any > sort of meaningful change then it effectively rules out PCM samples (unless > they used some sort of wavetable thing like a PPG, in which case it would be > quite overcomplicated as well as very poorly implimented...) > > You might also want to check out the noise source too and try to figure out > how that works. The idea of 4-bit PD is interesting. If it exists, it should have a real filter, not only our CZ's DCW. I haven't figured out what you are saying (because of my English...) But issue of decay sound led me to think that 4-bit DCO may not control volumes well. (Poly-800 can digitally control the DCO's volume in 32 steps. So extra 5 bits added - It may be called a 9-bit synth...) I will look into my HT's waveforms later. Best, Sealed HZ/HT page http://homepage.mac.com/synth_seal/html/ht3000.html
2002-08-24 by Scott Nordlund
>I haven't figured out what you are saying (because of my English...) >But issue of decay sound led me to think that 4-bit DCO may not control >volumes well. What I mean is that you should look at the waveform as it decays to see if it actually changes. I doubt the volume control part plays into the 4-bit waveforms, there would be a lot of quantization noise and there would be audible stepping in the volume envelope. I would imagine that the amplitude control comes after the waveform generation part. _________________________________________________________________ Join the world\ufffds largest e-mail service with MSN Hotmail. http://www.hotmail.com
2002-08-24 by Scott Nordlund
I just saw something of interest... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=897600132 first time I've ever seen an HT-6000 - if you want information you could email the seller and see if he would be kind enough to give you any wisdom. _________________________________________________________________ MSN Photos is the easiest way to share and print your photos: http://photos.msn.com/support/worldwide.aspx
2002-08-26 by Furman, Jon W.
Yeah I was inspired to plug up the old MT68 this weekend. It still works. It was like a time warp back to 1986. Lots of fun. I don't think that the drums can be filtered though, at least I don't recall that being a feature. Jon
-----Original Message----- From: sealed [mailto:sealed@...] Sent: Saturday, August 24, 2002 3:02 AM To: CZsynth@yahoogroups.com Subject: RE: [CZsynth] New HZ/HT page I looked at Synth Site and found a link to MT-68 demos. http://www.audiva-music.de/casio.shtml <http://www.audiva-music.de/casio.shtml> (Is he on this list?) I found the music very very amusing to me. Not only being an analog keyboard, its drums also analog! (Further, it may be filtered?) Sorry for being openly excited... (Jon, you liked it secretly...) Some presets may not be good, but the hardware itself seems to be very cool... Analog is what is admired today. CASIO made it very cool, cheap, compact, and especially, in a funny design... Best, Sealed HZ/HT page http://homepage.mac.com/synth_seal/html/ht3000.html <http://homepage.mac.com/synth_seal/html/ht3000.html> . [Non-text portions of this message have been removed]
2002-08-27 by sealed
As far as I can tell, HZ waveforms, if normalized, look the same when decayed. The volume control seems to be independent of the waveform generation part, as you suggested. > What I mean is that you should look at the waveform as it decays to see if > it actually changes. I doubt the volume control part plays into the 4-bit > waveforms, there would be a lot of quantization noise and there would be > audible stepping in the volume envelope. I would imagine that the amplitude > control comes after the waveform generation part.