Tutorial 1: Creating Killer Synth Sounds with the Wave Shaping command

In this tutorial, we use the new Wave Shaping command and the Filter window to transform a simple waveform into a rich and evolving sound source . We also use the new Tempo and Durations dialog box to set the duration of the picture played by the Image Synth.

Step 1. Computing a Sine Wave to Transform

In this step, we create a source waveform that will be transformed into a complex wave shape in Step 2. We also use the new Tempo and Durations command to set the duration of the picture.

A) Launch MetaSynth. (Quit and relaunch MetaSynth if it is already running). The default picture, which plays a sine wave at A 220 should be present in the Image Synth.

B) To give us a slightly richer starting point, we add a second sine wave one octave below the fundamental. Do this by holding down the option key and pressing  the down arrow of the Octave Transpose icon while still pressing the option key.

C) Set the fundamental
Note this display in the upper-right hand corner of the Image Synth window.  The display indicates that A2 is the fundamental (the reference pitch) associated with the picture. Clicking on the down indicator will move the picture's  reference pitch down an octave, giving us two sine waves: one pitched at 55 Hz. and the other at 110 Hz.

D) Filter the second harmonic
Use the marquee tool to select the second harmonic. Apply a fade-in preset filter to fade in the second harmonic over time. The picture should look like the first preset in the tutorial preset lib.

D) Set the tempo
Double-click the duration icon  to invoke the Tempo and Durations dialog box.

E) Set the duration to 0 minutes 7 seconds and 0 frames, and press the  button.

NOTE: By default, one frame is equal to a millisecond. This setting can be changed with the Preferences menu command.

F) Compute the sound by pressing the Compute Sound icon .

Step 2. Using Wave Shaping to Enrich a Waveform

In this step, we use the new Wave Shaping command to create a complex synthesizer-like waveform from the simple sound created in step 1.

A) Choose Wave Shaping from the Morph menu.

B) Grab the green line at any point and drag up or down to reshape the sample. Repeat this step a number of times, and you will find that a great number of overtones are added, turning the simple waveform into a much richer one.

C) When you are happy with the sound of the waveform (or when it is sufficiently ugly), press the icon to compute the waveform.

TECHNICAL NOTE: The green line in the Wave Shaping graph is the function used to remap the amplitudes of the source sample. The y-axis represents amplitude values of the source waveform and the x-axis represents the remapped values. When the line has a 45 degree slope, the resulting waveform is identical to the source.

(Tut1_soundA)

Step 3. Applying a Filter Envelope

Wave shaping can quickly add a large number of harmonics. In this step, we further shape the sound using the filter palette to give the note a filter envelope.

A) Bring the Filter window to the front.

B) Press the Analyze Current Sample button to show a spectrum analysis of the waveform we created in Step 2.

NOTE: The orange layer of the Filter window has no effect on the computation of the sound when the filter is applied, but it gives us an accurate picture of the frequency content of the source sound. When the filter is applied only those frequencies covered by blue pixels will pass through the filter.

C) From the pop-up menu, choose a filter like the one pictured below.

D) Apply the filter to the sample by pressing the Compute Sound icon . The sound is ready to be used in the Image Synth as a sound source in the sample or cross-faded sample modes. (Tut1_soundA flt) Save the sound by choosing Save from the File menu.

E) Bring the Image Synth to the front, and select the second preset in the tutorial preset library. The preset's input mode is already set to use crossfaded sample mode. Press the Compute Sound icon  to compute and listen to the result.

Notice how the resulting sound reflects the harmonic modulation of the input sound .(Tut1_soundB).

The third preset is another example, in stereo, that sounds great with this sound (Tut1_soundC). Don't forget to to type command-z to recover the original input sound (or you can reload the sound using the File menu's Open command) before computing this preset.

Conclusion:
This tutorial shows you another example of how to create a complex sound "on the fly" for use in the image synth.

IDEAS FOR FURTHER EXPLORATION :

Try applying Wave Shaping after computing a picture in the Image Synth. For example, select the second preset in the tutorial preset library and compute the sound with the sound source set to a sine wave (instead of a sample). Apply Wave Shaping to this computed sound. Notice how different the result is from when the wave shaping was applied before. (Tut1_sound D is an example of a sound created with this technique to which a sine wave shaped Pan Envelope was applied)..

Try iteratively wave shaping and filtering. Follow steps 1 through 3 in the tutorial above and then repeat steps 2 and 3 several times.

Save several sounds created with different wave shaping contours. Compute the same preset with each of these sounds as the input source, and crossfade the resulting sounds.