GENERATING THE SOUND OF MUSIC
FOR THOSE with a musical bent who have a Sinclair machine, help is at hand. Not a musical bent straightener but the Trichord from Petron Electronics, a stereo programmable sound generator board, available in two versions, with and without an internal amplifier and speaker, for both the ZX-81 and Spectrum. The Spectrum version can also have a BEEP amplifier built-in.
The Trichord has three basic modes of operation. First, using an inbuilt PROM, it can reproduce any of 255 sound effects ranging from one described as a 'low bong' to a steam engine and whistle, plus many indescribable ones. Second, it can be used to play three-part harmony and, finally, the internal registers of the PSG chip can be accessed to produce your own sound effects. Programs on a tape supplied with the unit demonstrate those features.
Once the information about a sound has been fed to the PSG it will maintain that sound without continuous computer updating, making it ideal for use in games.
All versions of the Trichord are in the same-sized black plastic box which has a ZX-81 connector and through port. On a Spectrum that means only a Sinclair printer could be plugged into the back of it.
With prices ranging from £24.95 for the ZX-81 version to £29.95 for the Spectrum version with BEEP amplifier, the Trichord is probably the most versatile sound generator on the market at the price. The manual is available separately at £1.25.
Petron Electronics is at Courtlands Road, Newton Abbot, Devon TQI2 2JA. Tel: 0626-62836.