K5synth

On August 31, 2003, I emailed Andy Bridle and asked him if there was any chance he 
might create a real-time version of AdSyn32, his non-realtime additive synthesis program, 
to which he said, "I'm working on it". Today, I received a notice from him that he has 
released AdSynDX, a real time DirectX additive synthesis program. It looks like it has all 
the features I've dreamed of, including inharmonic partials, resynthesis, pitched noise 
partials, etc. 

Joel Braverman
Moderator

From http://www.bridle.demon.co.uk/adsyn.htm

AdsynDX 


AdsynDX is a sound synthesis application for Windows XP; it creates audio waveforms 
using the methods of additive synthesis, constructing complex waveforms by adding 
together sine waves, of various frequencies and amplitudes, known as the partials or 
harmonics of the resulting wave. Any periodic waveform, i.e. a sound with pitch, such as 
that produced by a musical instrument, can be described by such a set of sine-wave 
partials, and the set can be derived from the original sound by applying a mathematical 
procedure known as the Fourier Transform. The relative amplitude of the various partials 
is a function of the acoustic properties of the instrument, and the way it is played. The 
dominant partial, known as the fundamental, is usually the partial with the lowest 
frequency, and is largely responsible for the perceived pitch of the sound. The other 
partials are usually harmonically related to the fundamental, i.e. their frequencies are 
integer multiples of the fundamental's frequency. The harmonics, and their relative 
strengths and dynamics, give the sound its characteristic tone, or timbre.  Additive 
synthesis attempts to recreate an instrument's timbre (or create new, possibly non-
instrumental, sounds) by adding and mixing partials.


AdsynDX allows the use of an unlimited number of partials (subject to memory 
constraints), and, with a suitable soundcard, can handle mono and stereo waves at 
sample-rates up to 96 kHz. In addition to simple sine waves, AdsynDX can create partials 
based on non-sine wave-tables, and partials containing one of two types of noise: random 
(or white) noise, and the more natural-sounding fractional (or pink) noise. Partials may be 
harmonic (i.e. integer multiples of the fundamental frequency), or inharmonic (producing 
non-musical or bell-like tones). Each partial's amplitude is controlled by a fully-editable 
envelope, and a mixer section allows easy control of the partial mix. For 2-channel 
(stereo) waves, the partials on each channel can be detuned, and the phase of each 
channel adjusted, to produce dynamic stereo effects. AdsynDX will also create waves 
based on a harmonic analysis of an existing audio (.wav) file, and from recording sources 
connected to your soundcard.