Dave explains how you can get a really nice, authentic synthetic brass program on your monosynth.
I believe it's a good idea to understand how to make your own synth sounds from first principles as this means you will easily be able to modify the sound to your particular production. With this in mind I have set out below how to go about creating a convincing trumpet sound on a basic analog synthesiser using standard waveforms and filters.
- Initial wave is a single, monophonic triangle in an appropriate register for instrument type. Extra VCO's with drift can be added for a 'tutti' group effect.
- Amplitude: Velocity scale around 4db.
Amplitude envelope (semi-exponential): Attack and decay can be velocity scaled around -10%. Typical Attack times are plosive: 0, hard: 100ms or soft: 200ms.
Sustain level around 80%. Release around 30ms, more for tutti.
- Vibrato: Depth of +10 cents is applied overall to the patch. LFO is triangle at 5Hz and depth is by external controller. An extra envelope should delay and fade-in the effect by 70ms.
- Tremolo / amplitude modulation depth is externally controlled. LFO is triangle around 8Hz. Should be delayed 100ms until Amp Env Sustain section is reached.
- Diminuendo/swell can be extenally depth controlled or by an extra envelope that increases the sustain level after a delay as above.
- Filter: Either 12 or 24dB low pass, algorithm and overdrive to taste. Keyboard tracking to around 90% making higher notes less bright. Resonance 20%. Initial cutoff 200Hz.
- Filter cutoff envelope (semi-exponential): Depth around 4 octaves, but magnitude is velocity scaled to around 50% making louder notes brighter. Channel Aftertouch can also increase envelope depth to add brighness during sustain.
Attack around 100ms but with a little negative velocity scaling.
Decay around 100ms, sustain 80% and release 30ms.
- Growl is filter cutoff modulation by a triangle LFO at 80Hz that adds a brass signature sound. Depth of -16 semitones is modified by extra envelope so that it only affects the first 50ms of the note. Can also be re-introduced in the sustain phase with an external controller. LFO waveform could be deformed to a comb shape.
- Noise undertones. Mixed in on a separate channel with simlar amplitude and filter modulations and should be mostly White, though tending towards a darker sound. A comb filter with positive feedback and at 50% wet/dry mix, tracking the keyboard with a cutoff of 523Hz (an octave above middle C) gives a convincing sound of air. This should be at about 5-10% of the main oscillator level.
- Portamento and pitch bend are added to taste depending on playing style.
I'm afraid I have used rather technical language to describe the process, but this is the easiest way to expalin how the controls on you machine should be set. For further explanation of the terms used please consult your user manual, search the all-knowing inter-web-thingy, or contact me or leave a comment below.
A big thank-you to Gordon Reid author of the amazing Synth Secrets
series, which is recommended reading for any synth programmer.
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