stereo-pads

stereo pads

Figure 8 summary

• wrapper for synth and channel
• receive global chord list
• play it all as pad

First synthesiser wrapper

This patch is typical of a wrapper. It is mainly a way to tuck two or three related things in a box together. We have a synth part which is going to play some audio and all the global messages needed to make that work, in this case only [r chords], and we have a mixer channel with a few extras to implement a channel mute.

Figure 8: G1-stereo-pads

G1-stereo-pads.pd

pad synth

Figure 9 summary

• unpack 8 notes
• 2 x oscillator bank
• panning and effects

synth gubbins

All the notes from the chord are unpacked and sent to separate oscillators. A [phasorblock] each contains 4 phasors so we have one half of the chord going to the left side, and the other to the right side of a stereo chorus/delay. The amplitude decay time of the synth, which is processed by [stereoamp], is set to 4 times the current period, so it will move automatically if there is any tempo change. Locking synth parameters to global variables like tempo is very useful, you may have many lfos all running in synchrony if you use a fast timebase by running the metro at 16 times the drum speed to broadcast a time value from which message rate lfos can be derived.

Figure 9: G2-padsynth

G2-padsynth.pd

oscillator bank

Figure 10 summary

• 4 x phasor
• separate [mtof]
• remove dc offset
• scale quite low

phasor bank

Bunching up a load of osc sources in one signal abstraction is quite typical but with phasors we need to remember to remove the DC offset because a phasor is not symmetrical about zero. There are clever ways to reuse a [mtof] if we have lists of notes, but it is a very inexpensive unit so we opt to have separate inlets and separate [mtof] for each voice.

Figure 10: G3-phasorblock

G3-phasorblock.pd

stereo pan delay

Figure 11 summary

• slowly moving random line
• variable delay for pitch shifting

tones for composing with

When setting the mood for a piece by choosing some chords it often helps to use "big" sounds. Rich sounds in certain timbres suggest things harmonically. Pure sine waves don't give the potential for suggesting harmonically related chords because they have no overtones of their own. A way to get a richer sound from fairly weak sawtooth waves is to employ a chorus or vari-delay effect.

deep swirly effect

Instead of a regular lfo that sweeps back and forth over a fixed period we have a wandering control signal. This is used to sweep two bandpass filters with a slightly less bright version going to the delay. Delay unit [vd~ $0-ffff] is a vari-rate delay with its time in the range 10 ms to 50 ms and swept by the same wandering signal. This results is a rather old fashioned, warped kind of effect with occasional fast excursion that make the sound go out of tune.

Figure 11: G4-stereopandelay

G4-stereopandelay.pd

stereo amp

Figure 12 summary

• long envelope
• channels linked

long amplitude envelope

To control both left and right outputs of the chorus together we need a stereo envelope. The control signal holds for about twice the decay time, which in this case is 16 times the period. Look back to the [padsynth] to see we used 4 times the period. This gives a soft fall to the pads so they don't play in a constant dirge, slightly more string-like than organ.

Figure 12: G5-stereoamp

G5-stereoamp.pd

play the pad line

Figure 13 summary

sound of the pad synth

Only one fader is up on the GUI, panned to the middle. There are no other parts in the piece at present. Experiment with panning and fading the part. Test out the on/off (unmute buttons) and resetting the timebase. Try putting different notes in the score chord lists.

Figure 13: G6-pad-line

G6-pad-line-play.pd G6-pad-line-play.ogg