The Internet HTML Synthesizer Patches Form

by J H H Lowengard

Here are a couple of ready-made "patches" of popular synthesizer noises which have already been worked out, while leaving a few parameters available for you, the user, to fiddle with.

Different Waves

The shape of an audio wave form determines its harmonic content - and therefore its timbre. This patch lets you change the wave form of a sound and applies different envelopes to it as well, making this just about the simplest "useful" patch in the history of electronic music.

[A suggested range of values is put in square brackets]
Frequency [50-1000]:
          Wave type:
Modulation Envelope:
  Sound File Format:

Frequency Modulation

Frequency Modulation (FM) is a synthesis technique popularized by Yamaha's DX7 and related synthesizers of the early 80s. In this patch, you can change the frequencies of the carrier and modulator, and also the "modulation index," which is how much the modulator influences the carrier. This index is itself modulated by a small selection of envelope shapes.

[A suggested range of values is put in square brackets]
  Carrier Frequency [50-1000]:
      Modation Index[10-100]:
 Modulation Frequency[1-2000]:
          Modulation Envelope:
            Sound File Format:

Low Pass Filter

The Low Pass filter is the soure of the classic analog "Bwowp" and "Waaaa" noises, which are made by modulating the resonance and cutoff frequencies. Filters change the amount of a sound's energy that lies in a certain range of frequencies, sometimes boosting it, other times removing it. A Low Pass filter removes or quiets sounds with frequencies above a cutoff frequency. The resonance determines how sharp that cutoff is (and also emphasises the cutoff freqency somewhat - setting the resonance very high will turn the filter into an oscillator!)
In this example, either a square wave or a noise source can be filtered since both have lots of energy in their high frequencies. This patch will sweep the modulation frequency from one (low) value to another (high) one and back again.

[A suggested range of values is put in square brackets]
                       Wave type:
   Low Cutoff Frequency [50-100]:
High Cutoff Frequency [200-2000]:
                  Resonance[0-5]:
               Sound File Format:

Duty Cycles

A duty cycle is a technical term describing the way certain wave shapes are distorted, which in turn changes the way they sound. In this synthesizer, only the Square and Triangle waves can have their duty cycles changed. A square wave with a duty cycle new 0% looks like a narrow, positive going spike, similarly, near 100%, it looks like a narrow negative going spike. A triangle wave near 0% becomes a "down sawtooth" wave, and near 100% it resembles an "up sawtooth" wave. When a duty cycle is near 0% or 100%, there is more high frequency content than when it is at 50%. This patch sweeps the duty cycle of these two waves between 0% and 100% which results in a familiar phasing-type sound.

[A suggested range of values is put in square brackets]
                       Wave type:
             Frequency [50-1000]:
               Sound File Format:

Sequencer

A newer feature of analog synthesizers was the sequencer, which was a way to change parameters of a sound module in a repetitive, predicatable manner. The sequencer here lets you play with 8 values, which in this example are used as frequencies for a simple oscillator. You can either select a preset sequence or type in your own frequencies by selecting "Custom".

Sequence Name:
         [if custom is selected, these values are used instead]
1:2:
3:4:
5:6:
7:8:

               Sound File Format:

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Henry Lowengard, jhhl@panix.com / 295 St. John's Place #6B / Brooklyn NY 11238-5642 © 1999 Henry Lowengard