Envelope Editing
Envelope parameters may be edited either numerically or graphically. There are two curves, representing the hard velocity levels and the soft velocity levels. The small squares can be dragged with the mouse. As you drag, the values in the edit fields are update. The envelope values are immediately sent to the sampler.

Preferences
The preferences can be changed by selecting the "Preferences..." item under the Edit menu.

There are three categories.

In the MIDI section, these parameters are used to keep the sampler from getting too much data at one time. If you find that you get Time-out messages, increase the Delay times (in Ticks, or 1/60 of a second). Or you may want to decrease the Block Size so that too much data at one time does not overwhelm the sampler.

When saving AIFF files, a special Creator tag is applied to the file which is used to link the file to a particular application. By default, it is set to 'SCPL' which is the creator tag for SoundApp. You can find out the creator tag for your favorite waveform editor by using a software tool called a resource editor, such as ResEdit, or a disk tools such as Norton's Disk Utilities or a freeware application called CTC (which stands for Change Type and Creator), which is available on many Mac archives. You can also call the manufacturer of the editor to ask them what is their application's creator code.

The Color preferences allow you to customize the appearance of the waveform viewer. Click on one of the colored blocks and the Color Picker window will show up.