# Interacting with a patch

This document discusses different ways for interacting with a patch. You learn about

- Using the 3DO control pad for input
- Playing patches from the keyboard

## Using the 3DO control pad for input

When you play a patch, ARIA lets you observe the output signal with a simple oscilloscope on the TV monitor and interact with it using the 3DO control pad. To interact with the patch, follow the instructions on-line, shown in Table 1:

    Table 1:  Control pad input for interacting with a patch.
    --------------------------------------------------------
    Input                |Result
    --------------------------------------------------------
    Move cross left/right|Changes X scale of wave display
    --------------------------------------------------------
    Move cross up/down   |Changes Y scale of wave display
    --------------------------------------------------------
    Shift left/right     |Scrolls wave
    --------------------------------------------------------
    A button             |Refresh
    --------------------------------------------------------
    C button             |Audio Monitor (see next paragraph)
    --------------------------------------------------------

### Audio Monitor

During patch playback, the Audio Monitor displays, in real time, usage of a number of DSP resources. The display shows the usage at the left as a numeric absolute value. A histogram on the right shows the usage as a proportion of the maximum available. If a patch is not working because it exhausts available resources, this histogram helps you find out which resource you have run out of.

Note: Future versions of 3DO hardware may allocate these resources differently; use them only as a rough guide.

Here are some of the resources Audio Monitor displays:

    -------------------------------------------------------
    TKR    |DSP ticks really used at this moment.
    -------------------------------------------------------
    TKA    |DSP ticks allocated.
    -------------------------------------------------------
    COD    |Code memory allocated. Note that this can
           |become fragmented.
    -------------------------------------------------------
    KNB    |Space for storing knob values.
    -------------------------------------------------------
    VAR    |Space for internal temporary variables.
    -------------------------------------------------------
    InF    |Number of FIFO channels (for example, for
           |sample playback).
    -------------------------------------------------------

## Playing patches from the keyboard

A 3DO DSP instrument has three phases: start, release, and stop. When you play a patch from the Macintosh keyboard or a MIDI keyboard, the patch is started when you press the key, and released when you release it. The patch is never stopped, so if you have no amplitude envelope to fade out the patch, or if you have an amplitude envelope with a release loop that continues to play after the release point, the note continues to play until you press another key or the space bar.

ARIA cuts off unstopped notes about 10 seconds after release.

### Using the Macintosh keyboard for input

While you're playing the patch, you can use the Macintosh keyboard as a mini-keyboard to play notes. The second row (q, w, e, and so on) has the black notes, the third row (a, s, d, and so on) the white notes on a piano.

### Using a MIDI keyboard for input

To play a patch from a MIDI keyboard, you must install the Apple MIDI Driver, MIDI manager, and PatchBay, as described in Setup for working with MIDI.