1 Welcome to the first batch of my technical tips. These pages are not just for hardware problems but also software and programming difficulties. Send your problems to, Andy Nibbs Tech-Tips 2 Seaview Hoylake Wirral L47 2DD These pages include: Explaining how sound samplers work Discussing MIDI interfaces
SOUND SAMPLING is performed by a small and cheap hardware device called a sampler and this simply converts the Analogue audio data into Digital data suitable for use by the computer. ANALOGUE data can vary infinitely and is so not defined in precise steps but as a voltage. DIGITAL data is represented by either ON or OFF , HIGH and LOW in digital electronics or 1 and 0 in computing. When strings of these 1s and 0s are strung together they can form numbers.
...This conversion from Analogue to digital is performed by an aptly named Analogue to Digital Converter chip, ADC for short. The BBC has a build in ADC for analogue joysticks but this is too slow for the frequencies in sound. The computer using the sampler must be driven by suitable software which takesa sample and saves it to disk. Once thesample is saved to disk, your own prog can load it and use a little machine code routine to play back the sample. The BBC's sound system however leaves alot to be desired when playing back samples and playback quality can be disappointing.
COMMERCIAL SAMPLERS: I personnally have not heard of any commercial sound samplers and so asked a friend to build me one. The parts for this came to around £20 and I am writing software for it for the highest quality sounds possible! Sound samples eat memory of course. SOFTWARE: I have written a program to collect samples in a sequence and play them back, this is for the MASTER128 only and is on ISSUE 3 of my MasterDisk for £1.50 and comes with some samples.
Q. Can DIMs be used in PROCedures A. YES. To connect a MIDI instrument to a BBC you need a MIDI interface which plugs into the 1MHZ bus. You can obtain an interface for around £80 from EMR. Who also provide plenty of software and expertise to support the system. EMR are on 0702 335747. Umusic also supply MIDI hardware and software and are on 081 788 3729. Hybrid make a MIDI interface to link in with their Music 5000 series, this is the MUSIC 2000 phone them on 0223 420360.