Inspired by Jonathon Harvey's Mortuos Plango, Vivos Voco, this patch enables glisses from one set of partials to another. Spectral glissing can effect a sort of timbral "morphing," much like the bell and boy sounds in the Harvey piece.

This patch analyzes incoming audio or a soundfile for the first twenty partials present; it finds the first twenty peaks in the frequency domain. It then sets twenty oscillators to these frequencies and corresponding amplitudes, making the audio seem to "freeze." The frequencies and amplitudes can be saved to one of two banks for later recall. The glissing function changes the oscillators from one set of partials to the other in the time specified.

The Patch

When the patch is opened, the soundfile "bell.aiff" is loaded into array5. The soundfile is set to loop, though you don't hear it until you set the amplitude of the loop in the upper-right corner:


You can choose the partial at which to start the range of partials recorded, set gliss time, start an analysis, and choose a single partial in four sections that act as controls for the recorded analysis.

By clicking "snapshot bang", you choose that point in the soundfile to analyze. If the oscillator amplitude is set (see the "Amplitudes" above), you will also hear the snapshot you've taken. You can take a snapshot without the loop-amp on.

The large boxes in the middle of the screen show the frequencies and their corresponding amplitudes of any saved snapshot. By clicking on "save1 bang" or "save2 bang" you will see the values change to reflect your current snapshot.

The frequencies

The amplitudes

Once two sets of partials have been analyzed and saved, they can be glissed in output from the part of the controls controlling gliss time.

Live input

A toggle switch allows you to switch between a live input or a soundfile.

The little section on the right allows you to make your own looping soundfile from a live source.

The Score

The score included with the patch simply steps through the simplest partial gliss from a live input. It is as follows:

0 0 comment --------------- STARTUP -----------------;
live-input 1;
0 1 comment --------------- EVENT 1 -------------------;
osc-amp 100;
snapshot bang;
0 2 comment --------------- EVENT 2 -------------------;
snapshot bang;
save1 bang;
0 3 comment --------------- EVENT 3 -------------------;
gliss 2000;
snapshot bang;
0 4 comment --------------- EVENT 4 -------------------;
recall1 bang;
0 5 comment --------------- EVENT 5 -------------------;
gliss 0;
snapshot bang;
At startup, this patch specifies that live-input will be used. At the first event, it turns the oscillators on by setting the amplitude at 100. The patch takes a snapshot of the incoming audio, which sets the oscillators to ring.

The next event takes another snapshot and saves it to the bank. At the third event after startup, Pd glisses from the first set of partials to the second.

The next event recalls the first set of partials. Event 5 changes partials instantaneously (glisses from one to the other in 0 ms).

The Mechanics

The sinusoidal analysis is done using Fast Fourier Transforms (FFTs). The fft patch is found in the "pd inputs" subpatch. The switches for soundfile versus live input are also found in "pd inputs."

In the fft subpatch, array3 and array4 display the frequency analysis done by the rfft~ object. These arrays are analyzed for peaks and sent to array1 and array2 by the pique object in "pd analysis" on the top page of the patch.

Array1 and array2 are displayed in "pd arrays." Their values feed the oscillator bank in "pd osc-bank" by going through "pd messpeak" and untangled in "pd unpacker."