What is ESD ?

Spectral Domain Framework for Synth Edit by Elena Design ("ESD") is an advanced library of modules opening to Synth Edit users the doors to realtime spectral processing, a technique also known as S.T.F.T (short-time Fourier transform).





From spectral filtering to pitch-shifting, from envelope extraction and pitch detection to voice processing, from sound synthesis to spectral analysis, there is no limit to the possibilities offered by ESD.
ESD allows you to design even complex spectral processing circuits within the consolidated visual real-time environment of Synth Edit, making of it an even more valuable platform, and a valid if not even better alternative to concurrent solutions, like Pure Data, Max/MSP, Python or MATLAB.





Exactly as a video is composed of frames, ESD processing is based on spectral frames. A regular audio signal is converted to a stream of spectral frames, whose size and overlapping factor can be freely set. Frames are transmitted thru standard Synth Edit BLOB lines and processed on a frame-by-frame basis, on a strict and sample-accurate time-grid, and ultimately stacked back and converted to a regular audio signal.



More than 180 modules are currently provided, covering all both basic and advanced spectral operations. Every module is written in highly optimized and clean C++ code and based on the internal ESD core library ("kernel"), which contains high technology and original algorithms especially developed by Elena Design basing on no previously published work.




The internal FFT / IFFT engine is an extremely efficient and optimized one, capable of transforming blocks of Real samples to Real ("half-complex") spectra and vice-versa, directly and with no intermediate steps, ensuring that only the amount of operations and memory accesses strictly required is performed.
However, Complex Fourier transforms are supported aswell, for research, experimental or special Complex Analysis purposes.





ESD includes a modern and advanced spectrum analyzer, which is fully configurable and can provide detailed information on every attribute of a spectral frame, including phase and peak estimates. Also, the internal scale conversion functions used allow mapping of magnitude levels all the ways down to silence (-oo dB), unlike most frequency analyzers where level display is clipped below some very low threshold, which is a very detrimental limitation for accurate analysis.






ESD is both suitable for real-time audio processing, R&D, experimental or didactical purposes and ultimately development of finished audio plugins - always with a moderate to reasonable CPU load. However, the advanced and motivated user who has also the proper DSP and coding skills, can condense whole spectral circuits into individal custom spectral modules, thanks to the optional SDK (Software Development Kit), for a real boost in CPU and memory performance (experience with writing custom Synth Edit modules is also required). ESD SDK is based uniquely on free open-source software (GCC and CodeBlocks), and can be obtained by Elena Design on special agreement.







Spectral Domain Framework was initially designed for private internal plugin development and research; in particular, its main purpose was providing us with some advanced tools to experiment with vocal timbre manipulation and vocoding.
Originally, we had no plans to release it to the public, judging it not suitable even for advanced users, given the quite vertical expertise required.
Eventually, the project grew and gained such a robustness and maturity that we judged a pity keeping it for us only; also, we felt that its release would have further increased the added value and populairty of Synth Edit, despite we still suspect that very few people are or will be able to master it fully - if at all.





Reading the manual throughfully and studying the many example projects included is mandatory before attempting to use this software. Spectral processing is by no means as intuitive as conventional time-domain processing. It has some strict and definite rules which must be understood first.
IN NO WAY YOU WILL OBTAIN ANY USEFUL RESULTS BY ASSEMBLING SPECTRAL MODULES INSTINCTIVELY !
A comprehensive PDF manual, rich with illustrations and with an appendix on advanced topics is now provided, covering all both basic and advanced aspects about ESD operation principles and discrete spectral analysis in general.

ENTER THE SPECTRAL DOMAIN !

Spectral Domain Framework for Synth Edit, its logo and the technology employed are © and intellectual property of ELENA DESIGN.
Synth Edit and its logo are © Jeff Mc Clintock, www.synthedit.com
ESD Logo is freely and obviously inspired to Synth Edit logo, software which it complements, representing the same spark ("ESD" also stands for Electro-Static Discharge) now striking a mountain, which represents Spectral Peaks.