Sampling CDs - New Orleans, the Delta Grooves, Technical Notes

Electro-Acoustic Modeling

All the loops that have the E.A.M. initials in the instrument description column are sythesized rhythms based on a new process developed by Ernest Cholakis called "Electro-Acoustic Modeling".

Used to create the solo kick, snare, hi hat and ride loops that are based on the "acoustic properties" of real world instruments but are actually generated using computer modeling. All the E.A.M. rhythms are derived from the rhythms that Dennis played. The number in the groove column lists the acoustic drum that the rhythm was extracted from.

Sample Electro-Acoustic Modeling (E.A.M.) Kick Drum Groove

Sample Electro-Acoustic Modeling (E.A.M.) Snare Drum Groove

Two key acoustic properties of drums have been emulated during this process. One is the change in timbre that occurs with dynamics in a real world performance and the second is that subtle but constant change in timbre that occurs because no two acoustic events ever contain the exact same timbre.

* One practical result of this process is that the actual sound quality of each of these loops is beyond the capabilities of any real world microphone in terms of signal to noise ratio and isolation or real world acoustic space. Each E.A.M. loop has absolutely no room ambience.

* All the E.A.M. Kick, Snare, Hi Hat and Ride rhythms are based on the the same group of drum samples, a couple of which are available in the upper register of the keyboard allowing them to be played simultaneously with the lower register of loops.This was done so that one can add ornamentation or creatively augment E.A.M. loops conveniently in real time.

Instead of mapping the samples in the conventional vertical manner with the a new sample every 4 midi velocity levels (1-4 Drum samples #1, 5-8 drum sample #2 ... 125-127 drum sample #32) all the samples in track 38-72 are mapped chromatically across the keyboard from F3 to C6. Track 37 has most of its drum samples mapped in a conventional 8 layer approach.

Sample 32 layer snare drum mapped out across the keyboard (F3-C6 ) 918k in GigaSampler Format

This nonstandard instrument mapping is used which extends timbral possibilities and gives a keyboard player a range of expression that approaches what a drummer can do. The sample at F3 contains the timbre of a drum sample played -70db and the sample at C6 is the loudest sample played at -0db level. Instead of having the F3 and all the other samples except C6 scaled to lower amplitude levels they are all at -0db containing a full 96db S/N ratio (16 bits resolution). If your were creating a snare performance with a traditional "dynamic" properties one has the option or adjusting the sequence so that a lower the pitch sample is always softer (lower midi velocity) than a higher pitch sample. Flams and buzz rolls sound more realistic with this type of patch than a conventional vertical approach (track 37). This was done to give the user more creative options.

* The signal to noise ratio of samples in tracks 38-72 are unachievable using any microphone. For example a mic with a 10db ENL (Equivalent noise level) noise floor and the sound is played at 60 db SPL the resulting recording has a maximum S/N ratio of 50db. With this new technology a real drum sample played at 40db SPL can be modeled to have a 96db S/N noise floor. This offers the contemporary composer and/or musician 32 levels of drum samples (snare/Kick/HiHat/TomTom) covering over 70db dynamic range all with a S/N ratio of 96 db !

Samples: Demo with several loops (736k), Bass and Drum Groove at 95Bpm, Bass Groove at 95 Bpm

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For further information contact Ernest Cholakis.