Tuning and Timbre Applet

by James Forrest

What it is:

This applet contains a software based FM synthesizer, and in the first screen you can specify details of the sound that you will play. The spectrum of the sound is calculated, and this spectrum is used to draw the dissonance curve, which plots the amount of sensory dissonance as a function of the interval.

The dissonance curve appears in an interactive window. By clicking anywhere in the window, you can hear the sound you have created played in the interval determined by the horizontal position of your mouse. (Notice the audible differences between intervals which are minima of the curve, and those which are not.) You may then choose a set of your favorite intervals and play them interactively. You now have a software synthesizer that plays a timbre of your own choosing, in the tuning you have specified.

How it works:

Decide on parameters for FM Synthesis by entering them in the fields below. You can also specify the envelope shapes for both the modulating oscillator and the carrier oscillator. You may edit these shapes later as well. If you check "Sync Envelopes", any changes you make to one envelope will be echoed in the other. In addition, you will see a volume fader. Use this to set the volume of the sounds if they are too loud or too soft. Tip: enter an index of modulation value of 0.0 to see the "underlying" dissonance curve--that is, the dissonance curve of pure sinewaves.

When you have finished entering in the parameters, hit submit and two windows will be launched. One window shows the spectrum of the sound you created, and the other shows the dissonance curve of that spectrum (as given by the procedure in Tuning, Timbre, Spectrum, Scale.)

Click on the dissonance curve to hear the sound played at various intervals (indicated by numbers on the x axis). If you like that interval, click the add to list button to add this interval to the list on the left. The lowermost interval in the list will serve as your "octave multiplier". Hit insert 12-tet intervals to quickly insert the 12-tone equal temperament intervals into your scale list. Click sort list to sort the list in ascending order.

Finally, hit activate keyboard and start pressing keys on the keyboard of your computer. 'Z' is the lowest note (specified by the base frequency you entered in the FM parameters section multiplied by the lowermost interval in your scale list). Move to the right on the keyboard ('X', 'C', etc.) to play the other intervals in your scale.

You can always go back and enter new FM Synthesis parameters to create a new dissonance curve. Your old scale will be recalled.

You can find out more about how dissonance curves are calculated, and what they mean.