Emax & Emax II

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visitors since 09/05/1996

My hope is to have experienced user's add to the section by writing user guides to getting the most out of the Emax. If you would like to contribute please email me.


A Guide to Spectrum Interpolation and Transform Multiplication

by John Silveria

Let me say right up front that I do not understand SE and TM very well myself. This guide is made possible because of the e-mail I get from other users and my own scouring of the net trying to learn more. If you have any hints, tips, or suggestions please contact me.

First you should read the Emax SE Upgrade Manual to get an overview also read the Keyboard Magazine report on the original SE Upgrade for the Emax. I suggest reading up on additive synthesis as this is the core of SE. Knowing Additive Synthesis will give you a good idea about the harmonic content of sawtooth waves, triangle waves, and so on.

In additive synthesis pure tones are added together to create more complex composite timbres. In theory a complex timbre which has been analysed into its sinusoidal components by means of some kind of Fourier transform can then be reconstructed by means of additive synthesis. This form of synthesis allows control over the individual simple components by means of individual envelopes for amplitude and frequency. Additive synthesis has the advantage that the many micro-variations in the frequency and amplitude of individual partials which make natural sounds so rich and lively can be recreated. The disadvantage with this form of synthesis is its inefficiency in that a great deal of data must be specified to define a sound of any complexity of detail.

Although I do have the SE Developement Disk for the Emax SE HD I'm sad to say that it will not work in the Emax II and I no longer have an Emax SE HD. SO I am unable to try out the suggestions in the manual.

Spectrum Synthesis is what is used to create the building blocks. Begin by learning to create spectrums which approximate a sawtooth, triangle, pulse waves etc. Once you can do that insert the spectrum at timeslice one, copy the spectrum to timeslice 24, and use function 6 to interpolate from 1 to 24 , then you should have a rough approximation of a each waveform which you can loop and use. Save all the resulting spectra.

The real fun is the interpolative function which gets you into quasi-PPG land. Put your sawtooth spectrum at Time Slice 1 and your pulse spectrum at Time Slice 12, interpolate between 1 and 12. Now put your saw again at Time Slice 24, and interpolate between 12 and 24. Now synthesise. You should have a fairly loopable sweeping wavetable-type sound wave now. When you've got use to a fair bit of this you can get round to designing progressively more complex spectra, with harmonics and inharmonics popping up all over the place save these to disk. Interpolate to taste. Add dash of re-sampling, digital re-tuning, chorusing. Spice with excessive gain boost, resonant filtering.

I'm sorry that right now this guide is probably not very helpful, as I learn or recieve more information I'll append this. Hopefully, I can get the specifics for creating individual waveforms.