Real-Time Sinusoidal Synthesis

Sinusoidal Parameter Streams

Many synthesis systems allow the user to operate on streams of stereo samples. Instead, we use streams of sinusoidal track parameters. We encode the parameters for the tracks such that operations which are normally applied to sample streams can be applied to these parameter streams. Frequency and amplitude shifts are achieved by adding a constant to a parameter stream. Timbre morphing is achieved through a weighted average of several parameter streams. Applying modulators, waveshapers, and filtering operations to parameter streams results in a wide range of timbral modifications in real-time.

Exporting Sum-of-Sines Files

• Use the mouse to select the track(s) which represent the fundamental of the Lemur file. If parts of the file have no clear fundamental, only label the parts that do.
• Select Label Tracks from the Edit menu and label the selected tracks "1."
• Use Select Tracks By Threshold from the Select menu to select tracks which exceed the analysis threshold by some amount (try 6 dB). Tracks which barely exceed the threshold will not be selected.
• Use Label Tracks from the Edit menu to label the selected tracks with the nearest harmonic number.
• All tracks which have non-zero track label will be considered for real-time synthesis. You may want to label additional tracks or zero the label on some tracks; do this if you have previously noticed problems in real-time synthesis.
• Use Export from the File menu to export an SOS file. You will be asked for a decimation value after you select the file; try 5. (Smaller values will result in longer SOS files, but usually they will not produce higher quality synthesis.)

Add the SOS file to your Kyma wavetables, and you will be ready for real-time synthesis.

More Information

For more information about Kyma, please contact symsound@shout.net.