Thanks for all the info. I have not done very well at finding what I am
looking for so far. The only decent Fourier analysis program I have found
is too expensive to be of use for me. $1K. I would agree that one doesn't
need to many harmonics to do a decent job, the Fourier series generator
idea I am playing around with is probably going to have 16. I'm hoping to
make up for the lack of higher harmonics by using either a HP filtered
sawtooth or a noise source to add brightness.
I would also agree that physical modeling is a better means of simulating
traditional instruments if you can get the algorithms close enough.
I am thinking of writing my own FFT analysis program for analyzing wave
files. If I do I will post a link to the group. I intend to share it for
free.
BTW you are the master of synthesizing instruments. I wish I had your ear.
(I am not worthy!)
-----Original Message-----
From:
elhardt@... [SMTP:
elhardt@...]
Sent:Saturday, June 14, 2003 7:22 PM
To:
motm@yahoogroups.comSubject:[motm] file uploaded, Additive Synthesis, Strings, Fourier, etc
OK, so I'm a little backlogged at responding to some old messages. This in
in
regards to all the talk about additive synthesis and whatnot over a month
ago.
Since a lot of this stuff is right up my alley (and I just uploaded a
related
MP3), here it goes.
Paul Haneberg writes:
>>I am wondering if anyone has any suggestions for a piece of software
capable
of doing analysis of a single note played by a particular instrument, for
example a wav file of a sax. I am looking for something that can give me a
time varying spectra so that I can see the individual envelopes of each
harmonic as well as determine the individual harmonic amplitudes.<<
Some standard sound editting programs like Sound Forge and Wavelab can give
you
3D time varying spectra plots, although sloppy and hard to derive useful
info
from a lot of the time. Otherwise, follow Pauls advice and search the net.
CoolEdit Pro can give you a realtime animated harmonic plot of instruments
as
they play or you can manually slide the pointer along a waveform and see
the
changes in harmonic amplitudes. Their FFT filter is great for filtering out
individual harmonics and listenting to them by themselves (a technique I
use).
>>Also helpful would be if anyone knows of a source (book or website) for
this
sort of information in a quantitative form, not just some general looking
graphs.<<
I've found almost nothing myself. There is supposedly a well known set of
harmonic graphs for most instruments, but those are only averages, and you
need
a different one for every note, and all the links to them are dead. For
strings
I've been analysing samples. Of course you either need to store different
harmonics for every note to preserve the formants of the instrument, or
come up
with a multi-band formant filter. If you go the formant filter route you
start
to defeat the need for additive synthesis in the first place.
>>It would be equally interesting if an analysis tool could easily show you
the
frequency response of an instrument body, if it could be done without
sticking
transducers all over the place and then applying a variety of excitation
sources.<<
Unfortunately the acoustic world is far more complex than it should be.
Resonances and dips in the frequency spectrum can move or disappear
depending
on the note being played. It's a mess that only my future synth engine will
handle correctly. However you can pick a range of notes and try to nail
them
down and hope the rest still sound pretty good. Looking at the harmonics of
a
violin note sliding up a couple of octaves up a string can help you see
harmonics get sucked into dips and pop up at major resonances.
Roger Rossen writes:
>>Additive synthesis has existed for quite awhile now- especially in the
academic sector - 'modulars' or software based ones for that matter have
been
around for quite awhile.Its a LOT of wanking around with minimal effect -
my
general proof: no major synth manuf. are pursuing it anymore.<<
It's all about user interface. Fairlight had it right. Just draw the time
varying envelope of each harmonic with a lightpen. Simple and Fast! 20
years
ago a wrote a program on the Apple ][ that did it that way (trackball
instead
of lightpen). It worked great. On the K5000, dialing in one harmonic at a
time,
and doing that four times, then connecting those to different points on a
multi-
segment envelope to morph between them, all from a little LCD window is the
most miserable hell a person can go through, and not very flexible either.
Additive is coming back because of the computer. There are two knew
softsynths
that are coming out just for additive.
Paul Haneberg writes:
>To achieve that goal, it would be musically useful to be able to generate
a
Fourier Series with complete control over the amplitude of each harmonic
over
time, which you certainly cannot do at present with the MOTM.<<
If you have a K5000, why duplicate that effort. You can just use your K5000
as
an additive oscillator to feed into your MOTM.
Ken Tkacs writes:
>>For certain tasks, such as Additive Synthesis, digital is pretty
necessary.
To do anything interesting, you need something like 128 oscillators, 128
amplifiers, and 128 envelope generators... then you need a way to control
it
all, and about three weeks to turn knobs<<
128 oscillators? The K5000 can only do 64 at a time, and I think the
fairlight
was 32. My MP3 demo only uses 18 for test purposes, and it's only a little
bit
less bright than the real sound. Interesting thing is I can filter some
sound
files so that instruments are down to between 1 and 4 harmonics and you can
still tell what instrument it is. For non-natural harmonic stuff, like
kettle
drums for instance, you're better off forgetting additive altogether.
Tobias Enhus writes:
>>Additive synthesis is a very valid technique to investigate.<<
Exactly. It's the only way to mimic some acoustic instruments almost
exactly.
>>There's an additive technique in particular, that I've used a lot in both
Csound and Kyma (with great results) and hope to recreate with MOTM
modules,
additive harmonic filtering (Paul Lansky). You feed a sound to
a bank of filters with high resonance tuned and enveloped to your specs.
This
technique captures more noise and enharmonic material which is very
important
ingredients of a natural sound.<<
One of those new additive softsynths claims to have a 128 band noise
filterbank. Sounds similar. For most acoustic instruments, that's not
necessary. But I've found with the human voice, there is a lot of breath
noise
going on between the harmonics. I've pieced together a file without that
noise
and the voice sounds synthetic. With the noise, it comes to life.
The following file is uploaded into the motm yahoogroups file section:
StringSynthesisElhardt.mp3
Some of you have heard the violin tone before, but this MP3 gives you a
Wendy
Carlos - Secrets of Synthesis (voice and all) style explaination as to how
it
was done. Plus you get a corny advertisement (I was just amusing myself)
for my
synthesis technique showing the awful results of current technology for
doing
string sounds, and the latest Nord modular samples using multiple delay
lines
(comb filtering), phaser, parametric EQs, wavewrappers, etc, to get pretty
good
strings sounds now, since "Microdetailed" synthesis won't be available
until I
write a synth engine to handle all aspects of it. Thanks to the Boss VT-1
Voice Transformer for helping me out with the voice overs.
-Elhardt
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