Phase Distortion: The halfsaw waveform. Useless. ?

[Sendy]

Not a very important post, this, but I was thinking about traditional Phase Distortion synthesis, in partucular, the traditional PD waveforms programmed into the Casio classics and hence all recreations of those oscillators. They all have a uniquely useful tone, APART from the halfsaw waveform.

Sure, it does sound slightly different from the regular saw, the fundamental is weaker, but in any musical context, for example, playing a chord, the wave is in all stages of distortion, pretty much identical to the regular saw. Just try it

Varying the duty cycle of a saw wave, i.e., varying the idle time at the end of the slope of the waveform, typically has little audible effect until the slope of the saw starts to turn into a pulse-like affair with a spike and a long rest period. Given that the halfsaw is a sawtooth with a 50% idle time, it's nowhere near different enough to a regular saw to warrant inclusion, IMO.

So it makes me wonder, why was the halfsaw included in the CZ synths, when there are countless more interesting waveforms hidden in the phase distotion engine, which you can hack out using sysex and other tricks, which could have taken it's place?

Once again, not a very important point really, but it's ALWAYS bugged me, every time I play with "classic" PD oscillators.

[Ch00rD]

Just a guess, as I'm not familiar with the CZ... but perhaps an oscillator with this waveform can also be used as a modulation source? In that case, it may not be so much the sound of the 'raw' oscillator itself, as its properties as a modulation source.

[Sendy]

Good guess, but you can't modulate from an oscillator in Casio's PD synths. At least, not until you get to their IPD system (interactive phase distortion) which came later and was much more like classic FM and didn't have these unusual waveforms (afaik, it had sine waves and various bandlimited saw approximations)

(and by classic FM I don't mean that dumb radio station that plays modern film themes and calls them "classical music" because they're orchestral )

[Ch00rD]

Good guess, but you can't modulate from an oscillator in Casio's PD synths. At least, not until you get to their IPD system (interactive phase distortion) which came later and was much more like classic FM and didn't have these unusual waveforms (afaik, it had sine waves and various bandlimited saw approximations)

Ok, that indeed seems unlikely then.

Next guess: perhaps it was very cheap to add, and the marketing guys liked the idea of an additional 'feature'.

(and by classic FM I don't mean that dumb radio station that plays modern film themes and calls them "classical music" because they're orchestral )

Oh you mean that Hans Zimmer stuff where it's sometimes not even a real orchestra, but a soft synth faking one?

[trance_lucent]

So it makes me wonder, why was the halfsaw included in the CZ synths, when there are countless more interesting waveforms hidden in the phase distotion engine, which you can hack out using sysex and other tricks, which could have taken it's place?

I can't answer your question, sorry, but I am interested. As far as I know, PD in Casio synths works the next way: modulator's waveform is used as carrier's phase counter value. And I thought that carrier is always the sine. So you speak about modulator's waveforms?
If yes (half-saw is used as phase counter of sine), then the result must be "squeezed" one-cycle sines with horizontal lines inbetween. May be not the most pleasant sound.

Edit: And, if Casio uses cosines, then the result must be something like impulse train with bell-shaped impulses.

[Sendy]

To clarify, the names given to the waveforms in Casio PD are referring to the waveform at full distortion. At zero distortion, the waveform is always a sine (or possibly cosine, to prevent discontinuties). The distortions to the phase accumulator aren't referenced at all in this case, since the distortion "knees" are all handled under the hood in "black box" style.

Hence, the halfsaw, when sounded with full distortion, produces a waveform which is half a saw and half "silence", which to all but those with golden ears, sounds identical to a regular sawtooth (albeit with a slightly weaker fundamental).

Here's a simple way to see what I mean. Load up Bazille (and as you do so you should shout BAZILLE! like you're an announcer introducing a boxer into the ring), set the "waves" knob to full so you get the full distortion, then switch the waveform box between "saw" and "halfsaw", playing various notes and chords. There is a difference, but it's subtler than even the mildest EQ.

If you aren't bored by now, try switching between the two settings with different values for "waves" (i.e. different phase distortion amounts), they sound similar across the whole travel of the knob

edit: It looks like the "halfsaw" has a slightly stronger 2nd harmonic, this is the only real difference I can find between the two. What I said about the fundamental being weaker is possibly wrong.

[xh3rv]

Does asymmetry through saturation etc. figure into this at all? I think I've seen the half-saw become more audibly unique in a situation like, when layering it through the filters with some drive. But I dunno if that's even here or there for the CZ units

[spacecult]

One important thing to consider is that wave 5 on a cz is actually a ramp wave and not a regular saw. For whatever reason, Bazille's 'half-saw' is just a half saw, and that's kinda too bad. So, whatever phasing occurs between the first and second voices will be a little different on these two synths. I don't know if Mr. Heckmann did this on purpose for some reason or if it was just an oversight.

Also consider that on a cz oscillator when combining waveforms they are not 'stacked' but are played in sequence creating a sort of 2 cycle oscillator. These 2 cycles, if each half is different, creates another period in the waveform which is naturally twice that of the source waveforms. So, combining them (waves 1 and 5) produces a kind of octavized saw sound. 2 lines on a cazio cz can sound very much like 4 stacked oscillators. Well, sort of like, depending on how picky you wanna be about it.

[Sendy]

Yeah, the effect of chaining a regular saw with a halfsaw is very cool. Saurus has a layered/octaved saw waveform like that as well, which is pretty cool to have on a standard subtractive.

I'll have to check out the halfsaws on other synths. If it really is a ramp on the CZ I'm guessing you could get a PWM effect by layering it with a saw on the other 'line'.

I'm pretty sure I heard u-he say they're planning on implimenting all of the CZ "hackable" waveforms, since a while ago I posted a link to a site which lists all of the waveforms you can make via Sysex hacking, and there are some really interesting ones.

I also find it weird about the CZ synths that there's no PWM pulse wave, with the waveshaper altering the duty cycle - after all, PWM is just a form of phase distortion if you look at it that way.

[Sendy]

BTW, here's the page with that table of waves (NOT a wavetable ) on it. Note that all of these waveforms show the wave at full distortion, you can get even more variation as they all behave differently to changes in the wave distortion parameter thingamabob.

http://www.kasploosh.com/projects/CZ/11 ... nique.html

[nativeVS]

Maybe it is useful in Ring modulation which was already possible in the original CZ synths.

[Halma]

Hey,

I chime in and hopefully can add something useful because since I had my first contact with PD synthesis I am totally lost to it. Love it so much.

Anyways, regarding to the purpose of the wiered waveforms:

Here is what the Casio Sound Synthesis Handbook says:

1. Saw-tooth: A bright tone color particularly suited to strings and brass sounds.

2. Square: A simple tone color suitable for woodwinds such as clarinet and oboe.

3. Pulse: A sharp tonecolor for funky sounds.

4. Double sine: A shrill, bright tone color.

5. Saw pulse: A brassy, metallic sound.

Reso I, II, III ...

And here is what Andrew Schlesinger says in his book "An Insider's Guide To Casio CZ Synthesizers" (btw he gave some of them custom names on his own).

1. Sawtooth Wave: ...most common waveform...contains all harmonics which become weaker the farther away form fundamental...full sound

2. Square: ...2nd most common waveform...only odd harmonics...hollow sounding...

3. Tri-Pulse: ...unique to Casio CZ...appears to be a combination of a thin triangle waveform and the "low" portion of a pulse wave...larger concentration of higher harmonics and a fundamental whose amplitude is much lower in comparison to sawtooth waveforms...very thin, reedy type...

4. Tri-sine: unique to Casio CZ...appears as a aombination of thin triangle and sine wave...one characteristic: its fundamental freq is an octave higher than of the other waveforms...strong fundamental and accentuated high harmonic content...

5. Sine-pulse: ...unique blah blah ... resembles one quarter of a sine wave attached to half of a square wave...sounds mellower than saw...with strong fundamental and slightly high harmonic content...fairly rich, mellow sound and functions well as an all-pupose waveform...this waveform usually ends up being used in conjunction with other waveforms...

Resonant Waves I, II, III

I thought that could be interesting (because Schlesingers book is so damn cool).

Regards
Sebastian

[Halma]

Maybe it is useful in Ring modulation which was already possible in the original CZ synths.

How funny you mentioned it. Because in the book of A. Schlesinger there are 20 patch examples with more indepth techniques and he is using [1:0] in dco1 and [5:0] in dco2 in RM mode for an ethnic percussion sound.

Regards
Sebastian

[spacecult]

If it really is a ramp on the CZ I'm guessing you could get a PWM effect by layering it with a saw on the other 'line'.

Well, I didn't mean to made it sound like it was a regular ramp.

It's really a half-ramp and kinda has a filtered shape to it as well. So, it doesn't really add and subtract with the saw wave completely right. (I'm going by the depictions on the face of a cz, the reality is a little different, though.)

But, believe it or not it does kinda work. It's not gonna replace anybody's juno, though.

Probably best daily use for me was to add some oscillator phase effect which can help the CZ mimic analog a bit better.

[Sendy]

Maybe it is useful in Ring modulation which was already possible in the original CZ synths.

How funny you mentioned it. Because in the book of A. Schlesinger there are 20 patch examples with more indepth techniques and he is using [1:0] in dco1 and [5:0] in dco2 in RM mode for an ethnic percussion sound.

Regards
Sebastian

That's really interesting. I wonder how different these patches would sound if you replaced the halfsaw with the regular saw? I'm going to check out some more VST PD implimentations. I still have ReFX's PlastiCZ because I think it has a really unique "chompy" sound.