@node "cards"

Using 16-bit sound boards with Mix mode

The Amiga's 8-bit internal sound capabilities are beginning to show their
age. As a result, several 16-bit sound boards have recently entered the
market. Three of them are supported by Mix mode.

With 16-bit samples, only volume values 0, 1, 2, 4, 8, 16, 32 and 64 can be
used. This means that note volumes may sound a bit strange if you change
Volume Adjust or the track panning. Also, the volumes you can use with some
player commands, such as Set Volume (type 0C), are limited to the above
values.

The Amiga's audio channels are now allocated only when they are needed for
the first time. So when using Mix mode with 16-bit boards, they aren't
allocated at all! To control audio channel allocation, use Allocate Channels
in the Project menu.

16-bit samples can be used with Amiga 8-bit and 14-bit output devices as well
as the three supported boards, although some of the bits are removed.

Toccata

To play through Macrosystems' Toccata sound board, select output device Toccata
16-bit in the Mixing Settings window.

Unlike in 4-channel mode, several notes can be played simultaneously through
the board in Mix mode. The mixing frequency is restricted to the fourteen
frequencies which Toccata can play, ranging from 5513 to about 48000 Hz.

The size of the mixing buffer is rounded to the nearest 512. Toccata is
usable with MIDI, if you use a high mixing frequency in combination with as
low a buffer size as possible (512 or 1024).

The support is implemented with toccata.library, which accompanies every
Toccata board. Any version of toccata.library can be used, but library
version V6 or later generally produces better results, allowing higher
mixing frequencies and reducing playing interruptions by other
system tasks.

MaestroPro

To play through Macrosystems' MaestroPro sound board, select output device
Toccata 16-bit in the Mixing Settings window.

Three different output frequencies are available: 32000, 44100 and 48000.
You should provide a reference signal to MaestroPro's input, and also set
the mixing frequency in OctaMED. If no reference signal is provided, its
internal 48 kHz clock is used.

The size of the mixing buffer is rounded to the nearest 1024. Usually,
however, a very large mixing buffer (about 32000) is required, although it
appears that smaller buffers also work fairly well. The larger the buffer,
the less suitable is MIDI usage, so be careful with large buffers.

As Macrosystems do not provide a support library for MaestroPro, it is
implemented with maestix.library by Richard Körber. A copy of this freely
distributable library is provided with OctaMED.

Delfina

To play through the Delfina sound board, select output device Delfina 16-bit
in the Mixing Settings window.

This mode uses the digital-to-analog converter on the Delfina board for high-quality
16-bit output. It does not use the DSP features available on the board,
only the output part. As of the delfina.library V2, six frequencies are
supported.

Support is implemented using delfina.library. Parts of the support code and
testing were done by Teemu Suikki.

The mix buffer can be 32 - 4096 samples in size with Delfina.

                          @{" Direct-to-disk recording " link "dd" 0}


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