BLIPPO SOUND EFFECTS GENERATOR (From Zebra Systems, Inc., $19.95)
The Blippo sound effects generator is a low-cost add-on module for the ZX81 or TS1000. It connects through the computer’s rear expansion port, and as all sensible peripherals, provides another expansion port at it’s rear. The module takes it’s power from the computer. Output is through a standard mini phone jack, which accepts standard earphone or mini speaker plugs. A speaker module with mating plug is available for $5.00 and comes in a neat little plastic enclosure. A volume control is provided on the Blippo module.
There are, strictly speaking 15 output tones available from the Blippo. How you combine these and how you time them determine the number of total sound effects you can derive. Each tone is implemented by poking a value between 1 and 15 to location 9000. Location 9000 is chosen because in the computer’s memory map it is not used either by the operating system or RAM. Poking these values gives you the discrete tones. Poking a 0 to location 9000 turns the sound off. You can also control the sound by using either fast or slow modes on the ZX or TS. For example, if you use a FOR/NEXT loopand sequentially poke the values 12-4 into location 9000 in slow mode, it produces a very musical sounding arpeggio. I use this type of sound for announcing a new spaceship, a victory, a move in the right direction, etc. If you use the same routine in fast mode, however, you get a single blast from an alien photon laser. Nesting this same routine in another loop will give you several very believable bursts from your laser. Reversing the same loop (poking 4-12) in either mode results in a sound of similar quality but opposing feeling. Adding delay loops alters this same routine still further. Keep in mind that these are all variations on one routine. Along with the instructions, which were adequate, came sample routines for eight different sound effects ranging from a telephone ringing to a police horn. Any of these routines (or any others you create) can be called from within a program as a subroutine and used as many times as you like. The sound effects possible with the Blippo module are varied, although not all encompassing. If you have any notions of multi-channel music synthesis or 21st-century wave-shaping, you’re looking for a more sophisticated (and much more expensive) unit. But if your ZX or TS exhibits the personality mine does, it cries out for the added dimension of audio communications with the outside world. I’ve found that one of my favorite uses for the Blippo is ‘Blippizing’ my favorite programs and adding audio prompts to existing utility and home budget programs. It’s like hearing a mutespeak. I wouldn’t be without mine.