The Eat at Joe's Kawai K5000 Message Board Digest
Additive Synthesis and Formant Filter Theory Overview
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Overview on K5000 systhesys
Monday, 05-Jan-98 14:03:12
Message:
143.182.246.27 writes:
Just picked up a K5000R. I was knocked over by the sounds it made it the store.
I became quickly depressed when I read the user Manual. The Manual
seems like a decent reference. What I am looking for is an overview on the
the beast works. This seems to be a very complex machine. I bought it for it's
sonic potential. It's been fun twiddling presets but I really would like to
understand how this works. By the level of some of the messages here it seems that
there are some very sharp K5000 users here. Please point me in the right
direction with respect to this mysterious machine. Thanks--- Ken
ken_j_cardita@ccm.intel.com
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Re: Overview on K5000 systhesys
Monday, 05-Jan-98 16:18:33
192.86.155.91 writes:
The architecture itself isn't all that complicated once you figure it all out in
the first place. The problem is that additive synthesis is so deeply rooted in
audio theory, that you really can't tell what the manual is even talking about if
you don't know some of the basics. I can't think of a good primer on sound theory,
but here's a brief overview of the K5000:
You have six sources (six "oscillators") per patch. Each of these can be either
additive synthesis or PCM sounds. PCM sounds are just looped (or unlooped) samples,
and much less powerful than the additive engine.
Now for additive...
Every sound you hear is comprised of several different frequencies. Most musical
sounds you hear are comprised of a fundamental (the note you hear), and overtones
(which are other, higher notes that are part of the sound). The reason why you
hear only one pitch instead of all of the different tones making up the sound is
that usually the fundamental tone is louder than the overtones, and also because
your brain is designed to automatically locate the fundamental (usually the lowest
tone in the series). Anyway, sounds are different from one another in large part
due to different overtones in a sound.
Sorry if you already know all of this, but this relates to the K5000 in that with
the K5000 you have independent control over each of the overtones in a note.
This makes the K5000 much more powerful than other synthesizers in some respects.
That's what all of that ADD stuff is. You can set values (and volume envelopes)
for each of the overtones. This represents a bottom up approach to sound
creation (adding componants) - as opposed to traditional synthesis, which starts
with all of the harmonics and then filters them out. Of course you can use the
traditional filter and resonance on the K5000 to do the topdown approach too,
so really you're squeezing something out in between when you make sounds
on the K5000. This different style of synthesis explains why the K5000 can make
sounds that you just don't hear on any other synth.
The formant filter acts as powerful kind of EQ filter. You can set EQ settings
for your sound, and then have those EQ settings evolve over time. It's kind of
like a graphic EQ, but it has 127 bands instead of the usual 6 or so, and you
can also create envelopes for each frequency.
If you just want to get started quickly, you can just copy additive (and formant
filter) settings from other patches. Some of them are saw waves (the standard
traditional wave form). They will include every overtone and gradually decrease
in volume toward the higher overtones.
You can also play with the knobs while you are editing the patch and then save
the patch. It will save changes you make with the patch (be
careful though if you aren't trying to do this).
In any case, this is a very mathematical instrument, which is why we wanted to
get mathematical specifics regarding the values of all the settings from Kawai.
Is that the info you wanted or is there something else?
Maybe someone else can give their overview as well, or fill in some of my blanks.
I see the message board digest turning into a FAQ in the near future....
Kenji
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Re: Overview on K5000 systhesys
Wednesday, 07-Jan-98 18:14:37
192.28.2.19 writes:
I haven't found any books yet that are directly on the subject of additive
synthesis. I've ordered some books on the basics of sound and music which may be
helpful; I'll post anything good.
There's some interesting stuff about the harmonic series in the encyclopedia,
under "tuning." People debated for centuries what the right way to tune a piano
would be. The problems arise from the fact that the harmonic series doesn't quite
fit into even divisions of notes and scales. Anyway, there is some useful
discussion of the harmonic series there.
Also look under "Fourier". Additive systhesis is sometimes called Fourier systhesis
because it is based in part on the mathematics he discovered. Also "Pythagoras",
who discovered the harmonic series in ~500 B.C.
Hmm, maybe I'll write a book . . .
leiter@skypoint.com
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Formant n' Macro Q
Tuesday, 17-Feb-98 06:03:02
147.151.166.74 writes:
Hello K5000 fanatics. I love the synth... manual is desperate though (sigz).
I have two questions which I hope someone won't mind answering. They might be in
the manual, but I certainly didn't get a clear answer from it.
i) how do you save the current macro settings to your patch? Very useful so that
you don't need to send all 16 knobs at the begining of every song via midi. I
read that someone knew how to do this. If I juSt choose "write" it never saves
the macro's.
ii) anyone care to explain what the formant filter REALLY does? It just isn't
ennough to twist the knob and get an interseting peep. Math won't scare me... the
more technical the better. Didn't find any explanation in the manual for this
one either...
8p
I'm very greateful for this site... it has been a few months that I've been
looking for a useful place for the K5000. My warmest greetings to you all.
Sebastian.
Plush Studios.
Amsterdam.
schedal@hotmail.com
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Re: Formant n' Macro Q
Tuesday, 17-Feb-98 16:58:59
192.86.155.91 writes:
<<FIRST PART CLIPPED AND MOVED TO "SAVING MACRO KNOB SETTINGS">>
2. You can look at the formant filter either as a customizable EQ that changes
over time, or as a shapeable VCF type filter, but in the end these both mean
pretty much the same thing. Subtractive synths (most synths that use the
VCO/VCF/VCA architecture are subtractive) typically have some or all of the
following filters: lowpass, highpass, bandpass, etc... Combined with resonance,
which creates a peak at the cutoff point, this process creates a shape for the
filter dependant on the settings. This, combined with the different waveforms
you can select (which are defined by the differences in their harmonic series' -
which means that once again the K5000 can achieve a much greater range by using
additive synthesis, which lets you custom shape all of the harmonics)
generates the timbre characteristic of a subtractive synthesis sound (not the
K5000). With formant filter you can create a much larger number of different
shapes to filter your tone by creating your own filter shape in the editor.
Furthermore, not only can you apply an envelope to the filter bias (the filter
frequency), as in subtractive synthesis, but you can also apply envelopes to all
of the different frequency bands. It's really pretty amazing - and that's why the
K5000 is so cool. With additive synthesis and the formant filter it should be
able to do everything subtractive does, plus a whole lot more!
For one given note, you could also create a patch that sounds like it's filtered
without using any filters at all - subtractive or formant. You would do this by
editing each of the harmonics so that they get louder and quieter at the right
times (I think Jens' emulation of pulse width modulation does just that - it's
really neato). This of course would be alot of work, which is why the envelopes
for individual harmonics aren't used as much as they could be.
What makes the formant filter process different from this harmonic shaping process
is the fact that it generates it's frequency shape from specific frequency
values (which are listed in a table in the manual - and can be modified and
modulated with the "bias" control) as opposed to the additive process, which
generates it's frequency shape from the harmonics of the note, which are relative
to the fundamental tone (which in an ideal - and typical - situation is the note
you press on the keyboard).
What all of this means is that on the K5000S you have three different ways to
create filtering effects (not including LFO's) - as opposed to the one envelope
you usually get with subtractive synthesis. You could generate some incredibly
complicated envelopes with this machine, because these can all be running
(adding and subtracting form each other) simultaneously for an overall effect.
I could be wrong, but it seems that there has yet to be written a patch that takes
full advantage of *everything* the K5000 can do - it would just be such a large
amount of work and also really hard to keep control of everything when it gets
so complicated.
Hope all of my little parenthesis and ramblings didn't confuse anyone, but I'm
easily sidetracked.
-Kenji
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Re: where can i hear a k5000, and a question about it's synthesis
Thursday, 29-Oct-98 02:03:23
209.160.126.143 writes:
I'm not really all that familiar with the SY-55, so I can't tell you what the
differences are between it and the K5000.
Additive synthesis is the process where sine waves are added together. Each sine
wave has it's own frequency, amplitude, and envelope. This is based on the idea
that any sound can be broken down into individual sine wave components. If you
want to know a little more, here is a place to go:
http://www.neuroinformatik.ruhr-uni-bochum.de/ini/PEOPLE/heja/sy-prog/node4.html#SECTION00031000000000000000
Leslie
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Formant Filter Overview
Sunday, 31-Jan-99 04:03:59
153.37.12.22 writes:
---ugo wrote:
>
> could you give me a general description of what the
> hell it really does? (and what each band really relates to?)
>
> thanks,
> ~*ChriS*~
>
Chris:
Thought this might be of interest to other people so while I take the
time to write it up I might as well send it on to the list
and post it on the message board as well.
The formant filter is a filter for which you can customize the levels at
each frequency. In traditional analog synthesis you can usually select
between a couple kinds of filters - low pass filter, high pass filter,
notch filter, and band pass filter being the most common. Furthermore,
you have resonance, or Q, which creates a peak in frequency at the cutoff
point.
The filter will remove frequencies from the sound. By default it will
remove fixed frequencies, regardless of the note being played (so when
using a low-pass filter low notes will be less filtered than high notes).
That's where KEYSCALE comes in. The KS to Cut parameter will make the
filter frequencies follow the frequencies of the note being played (the amount
to which it tracks the note is dependant on the amount of KS). Not sure
if already know all of this stuff or not. You can hear all of this just
fiddling with the DCF settings.
Now a Low pass filter will have a frequency response something like this:
_____
\
Low Frequencies \_ High Frequencies
The high frequencies are getting cut out. Now apply resonance and it is
shaped like this:
___/\
\
Low Frequencies \_ High Frequencies
Notice the peak right before the frequencies begin to be filtered. This
accounts for the nasal sound you hear when you turn up resonance (if you
turn the resonance up and sweep the frequency cutoff low enough you will
hear the peak accentuating the harmonics one by one - almost sounds like
an arpeggio). The amount of resonance will determine how tall the peak is.
High pass filter looks like this:
_____
/
Low Frequencies _/ High Frequencies
You are now cutting out the low frequencies and only letting the higher
frequency components of the sound through. Resonance creates the same
peak behavior:
/\___
/
Low Frequencies _/ High Frequencies
You can select between the lowpass and highpass filter under DCF->MODE.
The DCF on the K5K doesn't allow you to select notch or bandpass filters,
but this is no big deal since you have the formant filter.
With the formant filter you can create a filter that has any shape you
want. You can recreate a lowpass, highpass, notch, bandpass filter and you
can add a resonance peak if you want. Furthermore, the formant filter
editing screen displays all of the formants (frequency values for the
filter) graphically from left to right ranging from the lowest to highest
frequencies of the filter. This means visually you can recreate the shapes
that I have drawn above (If you make the formant filter follow one of the
shapes above you should get an effect similar to that kind of filter). What
you see in the formant filter editing window will basically translate directly
into how the sound is filtered.
Each of the values you can edit in the formant filter represents a half
note - one key on the keyboard. There is a table listing the frequency and
note values of each element of the formant filter in my K5000S book on page
45. Unfortunately this table contains the only real data IN THE ENTIRE
MANUAL that they have given us on how anything works inside the K5000.
There is still another element, however, that effects the frequency range
of the formant filter values. This is BIAS. BIAS is an offset applied to the
entire formant filter range. If you raise the BIAS setting, the entire filter
will move up in frequency.
If you lower the BIAS, the entire filter will move down in frequency.
BIAS is like the traditional Freq. Cutoff setting.
If you create an envelope or apply the LFO to your formant filter, you
are modulating the BIAS setting (i.e. move the filter higher up and lower
down the frequency spectrum).
Finally, you can use KEYSCALE again to track the formant filter BIAS to
follow the frequency of the note you are playing. This has the same effect
that applying KEYSCALE to cutoff value on an analog synth has.
Anyways, this is the power of the formant filter: You can create a
traditional style filter using it if you want, but you can also create any
other filter shape that you want to create! It's very very cool and it is
definitely worth spending some time getting to know it. Fiddle around with
it and listen to how the sound changes when you change the parameters.
-Kenji
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