Hello all,
With all the recent talk about additive oscs and Ken's post here, I just had
an idea... (and the crowd goes.. "oh-oh"!) ; )
I spent a few hours last night programming some new sounds on my Kawai
K5000s additive synth. One thing that amazes me is the ∗drastic∗ effect that
the formant filter has on the overall sound.
∗∗∗ K5000 synthesis hierarchy note∗∗∗ Individual additive osc freqs.
(harmonics) are set in their own menus, then you can emphasize, de-emphsize
various parts of the spectrum with the formant filter, this is in addition to
the normal LP/HP filter section. Each of the above synth sections
(harmonics, Formant Filt, standard filter also have their own independant EGs
(!).
Taking this perspective on things (here's where the idea comes in), instead
of trying to implement a multi-partial oscillator module with individual
harmonics' control, how about using steep-sloped filters to
accentuate/attenuate the various harmonics generated by a harmonically rich
signal source. This source could be an existing osc being FM'd with an audio
range signal or sync'd oscillators, or anything else that will produce lots
of harmonics.
What gave me this idea was the extreme amount of attenuation of the MOTM 410
tri res filter. If you input a signal who's fundamental freq is outside the
filter's notch freq, you will not hear the signal at all.
So...maybe a combination of multiple steep bandpass/notch filters can
generate some interesting and usable spectra. This sounds similiar to a
vocoder, but instead of applying in that sense it could be developed with
more of a synth-slant such as: v/octave of all filter freqs, envelope control
over all filters, or even a static setting, which would then be further
shaped by the 420, 440 etc... Come to think of it, this is starting to sound
like a 410 on steriods... hmm... : )
Andrew Sanchez
In a message dated 12/6/00 1:24:01 PM Central Standard Time,
ken.tkacs@... writes:
> The problem with a graphic oscillator is that the visual shape of a waveform
> doesn't have much real bearing on what the sound will be. And changes to
> that shape aren't the least bit intuitive, and are generally pretty
useless.
> The concept sounds great at first---like you will be able to draw any
> waveform imaginable and have it at your fingertips. But the reality is that
> most sounds you get from it will be terrible.
>
> When I was in college I had proposed a similar Idea and an engineer friend
> mocked something up for me as a demo. It sounded like a great idea---draw
> ANY waveform!! When we played around with the prototype, our reactions were
> like... "oh." That approach is great for producing sounds akin to distorted
> 60-cycle hum (and not even in a good way...I like noise, but these just
> sounded like electronic 'problems'). We dropped the whole thing.
>
> That's why I get wary whenever someone comes out with a Wavetable-based
> oscillator boasting "99 banks of new waveforms," and then you look at their
> manual, web page, whatever, and they show scope traces of the "new"
> waveforms. "Here's the one that looks like a row of houses, here's the one
> that looks like an upside-down row of houses" (as if that would sound
> different), here's the one where every other cycle is a square or
> sawtooth..." And you ∗know∗ that they designed these new waveforms by their
> look, not with any regard to the useful portions of the spectrum that they
> offer.
>
> If they had really come up with some neat complimentary waveforms, I would
> expect to see an FFT of them, not just a scope trace.
>
> Ensoniq attempted to create some interesting waveforms for their ESQ
> machines. On their own, they are of limited use, but they were digitally
> designed to compliment the basic waveforms. These were then saved into the
> wavetables. They didn't have names like "row of houses" because they didn't
> look like anything simple. (Simple waveforms, like tri, sine, square, etc.
> are 'easily' made with analog anyway). Instead they were just called
> something like "Digital #2 with emphasized 9th and 10th partials."
>
> I'm not trying to be a wet rag on the idea; I'm just saying that the idea
in
> practice isn't anywhere near as cool as it sounds. You think you will have
> the ultimate VCO but really it just grinds out nastiness. Additive is
> different---there, as you, let's say, move a slider up, you can hear that
> partial coming into play, and it sounds good and smooth and continuous as
> you move it, just like a lowpass filter sounds as it opens up (not "just"
> like---I'm trying to explain the 'continuity of it). Just changing a thin
> slice of a graphically-divided waveform wouldn't work anything like that.
>
> When you go out looking for new waveforms, you have to ask yourself why.
> Certainly you want something different that the Big 4 to compliment them.
> But simple bold waveforms are "bottom heavy" by nature, with very strong
> fundamentals. That's why their shapes are so defined, if you know what I
> mean (that and phase). With subtractive synthesis you end up "brightening"
a
> tone by either adding another oscillator an interval higher (which is cool,
> but it imposes a 'spaced-out,' newly fundamental-heavy series higher up,
and
> the ear can identify that), or else you highpass filter, which is still
> trying to pull-up the closely-packed, upper harmonics from a waveform that
> had very little energy up there in the first place.
>
> What would be cool would be to have waveforms ∗designed∗ to be up there,
> with harmonic series' to match where they land when being applied to the
> base waveform (I don't know how to describe this stuff without paper).
>