[A6] What is fat anyway?

[Dr. Georg Müller]

"Michael E. Caloroso" schrieb:

> Everyone knows that tube amps are great for overdrive.  The trumpet is another
> good example of natural overdrive.  Its timbre is dynamic with air pressure - 
> soft timbre at low pressure, brighter with increasing pressure.  The alloys in 
> the tubes, the flare, and the valves all play their part in the timbre of the 
> trumpet.  The tubes are not entirely rigid and will resonate with varying 
> pressure, which alters the basic timbre by adding harmonics.  That is why it 
> gets brighter with increasing air pressure.

The mechanism in instruments like a trumpet involves a nonlinearity as part
of the dynamical system, whereas in a tube amp the signal is just passing a 
nonlinearity. I can recommend a good article on the topic.

McIntyre M.E., Schumacher R.T., Woodhouse J.: On the oscillations of 
musical instruments. J. Acoust. Soc. Am. 74(5), 1325-1345 (1983)

This is BTW the basic for most algorithms used in Physical Modeling.

> You cannot overdrive the circuits of a digital synth - it does not sound 
> at all pretty.  Signal generation in the digital domain introduces zero 
> overdrive, it is completely sterile.  Great for audiophile engineers but 
> not always appropriate for music.  If you want the overdrive and addition 
> of harmonics known to analog circuits, it has to be modeled in DSP code.  
> Which is not easy because the dynamic overdrive of analog circuits is not 
> easily reduced to a mathematical formula.

I have to object here, the mixer section of the MicroWave is creating a
very musical digital overdrive IMHO.

http://www.mysunrise.ch/users/georg.mueller/waldorf/SoftPowerHard.mp3

Georg.