Moonsound

Moonsound is a sound card released for the MSX home-computer system at the Tilburg Computer Fair in 1995. It was designed by electronic engineer Henrik Gilvad and produced by Sunrise Swiss on a semi-hobby basis.

The Moonsound arrived after Microsoft abandoned the MSX platform in favor of IBM PC–compatible platforms. The sound card was named after the accompanying Moonblaster software that was written to take advantage of the sound card's features.

Overview

Based on the Yamaha YMF278 (OPL4) sound chip, it is capable of 18 channels of FM synthesis as well as 24 channels of 12 and 16 bit sample-based synthesis. A 2 MB instrument ROM containing multisampled instruments was unusual for its time.^{[citation needed]} It came equipped with one 128 KB SRAM chip from the factory for use with user samples.

History

Two generations of the Moonsound were made. The first one is a small size PCB without a box. Later, a larger size PCB which fit into an MSX cartridge was made available. The later versions also had room for two sample SRAM chips resulting in 1 MB of compressed user samples.

Moonsound version 1.0 had one socket for user sample RAM, while Moonsound version 1.1 and 1.2 had two sockets for up to 1 MB SRAM. Some hackers and modders found out how to stack two additional SRAM chips resulting in 2 MB of SRAM.^{[citation needed]}

Sound effects

Sound effects like chorus, delay and reverb are omitted due to cost, size and usability reasons.^{[citation needed]} The Yamaha effect chip requires its own specialised memory and effect routing is basic. All 18 FM channels and 24 channels of sample-based sound shares the same effect setting. Creative step-time sequencer programmers made pseudo effects like chorus, reverb and delay by overdubbing or using dedicated channels to repeat notes with delay and stereo panning. This is effective but quickly reduces the musical complexity possible.

Specifications

Being based on the OPL4 chip, The FM registers of the Moonsound are compatible with the OPL, OPL2 and OPL3 chips. The MSX-AUDIO contains a chip which is similar to and also compatible with the OPL. Therefore, some older software can make use of the Moonsound's FM portion.

The 2 MB ROM contained 330 mono samples, mostly at 22.05 kHz at 12 bits, but with some drums at 44.1 kHz.^{[citation needed]}

The FM part of the OPL4 chip can be configured in several ways:

18 two-operator FM channels
6 four-operator FM channels + 6 two-operator FM channels
15 two-operator FM channels + 5 FM drums
6 four-operator FM channels + 3 two-operator FM channels + 5 FM drums

Four-operator FM allows for more complex sounds but reduces polyphony.

Eight waveforms are available for the FM synthesis portion:

Sine
Half-sine
Absolute-sine
Quarter-sine (pseudo-sawtooth)
Alternaing-sine
"Camel" sine
Square
Logarithmic sawtooth

The Moonsound audio's power supply is isolated from its digital supply in an attempt to reduce noise. It has a separate stereo audio output as it is not mixed with the internal MSX sound.

Software

As most developers were active in gaming software, many game companies such as Sunrise (in the Netherlands) developed and composed music specifically for Moonsound.

List of software for the Moonsound:

Moonblaster
- Moonblaster for Moonsound FM
- Moonblaster for Moonsound Wave
Moonsofts Amiga MOD file player for Moonsound
Mid2opl4 midi file player for Moonsound
Meridian SMF MIDI file player
MoonDriver MML (Music Macro Language) compiler^[1]

Moonblaster is a software designed by Remco Schrijvers based on his time-step sequencer software for other MSX sound cards. Later on, Marcel Delorme took over the software development for Moonblaster. It was made for use with the Moonsound, of which the program's name inspired the name for the sound card itself. The software came with two separate programs, one for FM and one for sample-based synthesis.

Additional software tools were able to rip sound loops digitally from audio CDs inserted in a CD-ROM drive connected to any of the SCSI and ATA-IDE interfaces. These programs were developed and designed by Henrik Gilvad for MSX Club Gouda and Sunrise Swiss.

The Moonsound has also been emulated in MSX emulators such as blueMSX and openMSX.

References

^ "News » Music » MoonDriver 070528". MSX Resource Center.

External links

[1] "News » Music » MoonDriver 070528". MSX Resource Center.

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