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Re: FM?

To expand on Olivier's response, the way the frequency modulation
was used was to make the modulator frequency similar to the
carrier, typically a small integer ratio.  Thus, you don't get a sweep
or warble like you might expect, but instead the waveform is
warped over the course of each cycle and returns to the same point.
Changing the ratio and amplitude gives a large variation in the
waveform (and spectrum) produced.  This allows a small number 
of parameters to have a large effect on the timbre, and FM was
especially easy to implement in hardware or software (compared to,
say, additive synthesis).  FM was particularly good for horn-like
sounds, which were hard to create with other methods of the day.

The problem was that there was no intuitive way to predict the
effect on the timbre from the parameters.  People just tried a lot
of settings until they found something they liked.  Or, more
commonly, they just used the canned presets that came with the
synth (designed via trial and error by experts) and never messed 
around with them...  pretty much like way modern synths are used.

With the advent of increasing computing power, FM was no longer
needed to keep computations down.  But on top of this, it seemed
to me that the public fascination with strange synthetic sounds
waned, and people wanted more realistic simulations that were
much easier to achieve via direct sampling methods.

Best regards,

Bob Masta

On 16 May 2006 at 15:26, superk wrote:  

> Hi, everyone,
> In Xavier Serra's paper, "Musical Sound Modeling with Sinusoids plus Noise",
> three types of parameter model of music are mentioned, that is, instrument
> model, spectrum model and abstract model. And, it said, "Abstract models,
> such as FM, attempt to provide musically useful parameters in an abstract
> formula." Here, "FM" refers to what? Does anyone know? 
> Thanks
> Superk (Kun She)
> intel_ghost@xxxxxxxx
> 2006-05-16