DK'Tronics 3 Channel Sound Synthesiser

Crash

KEEPING UP WITH THE SIDSES The Dk'Tronics three channel sound synthesiser is a fairly nifty little gadget which, for £30-odd, upgrades your standard BEEPing Spectrum to a machine with sound capabilities comparable to those on a BBC or Amstrad. Based on the AY-3-8912 programmable sound generator chip, the unit comes complete with a plug-in speaker and cassette based software to get you started. The chip itself has fourteen registers, which may be accessed from the BASIC 'OUT' command, and sounds may be controlled on the three channels available. This direct approach is probably not for the beginner, and to avoid total despair on the part of the new user Dk'Tronics have thoughtfully written some software which allows you to interact with the chip by driving a cursor round the screen. Displayed options may be selected with a single key press - or by pressing 'fire' if you've added a Sinclair or Kempston joystick. Adding a joystick is advisable, as it makes programming sound effects from the screen menu simplicity itself, as the software is really very slick, taking the pain out of experimentation and allowing the complete novice to start making a respectable racket very quickly! Using the demo Music Designer software, you are able to program up to three tunes (or sequences of sounds), using all three voices simultaneously and 'record' them into memory. Once you've set up a voice with the associated parameters of waveform (either tone or noise), enveloping, attack and decay and shape, notes may be entered into memory by moving the cursor up and down a keyboard displayed at the base of the screen and pressing 'fire' to enter a given note. As each note is added to your growing composition, it is played back to you, and a simple editing function allows you to space back to the last note added to the stream and delete or change it. The instruction booklet that comes with the unit is the tiniest bit impenetrable, but all the information you might require to program the unit directly is there. A little time spent experimenting with the demonstration software would certainly pay dividends if you wished to delve into programming the sound chip directly. Most people would probably be quite happy to stay with the software supplied. One minor niggle with the program is the fact that you cannot immediately hear the effect of changes you make to the wave formations - it's necessary to keep scampering down to the screen keyboard with the cursor to play a note, which can get a bit frustrating. The unit itself, quite naturally, fits onto the edge connector, and sound is output via a mini-jack socket on the top of the unit, which has a little volume knob for you to twiddle. Don't be surprised if you soon get disappointed with the effect of twiddling this knob when the speaker supplied is connected - the output level is little short of wimpy, and is better suited to headphones. Connecting the output to your stereo is also a viable option, especially if you want to hear the delicacies of the envelope shaper, but be careful. It would be fairly easy to damage your speakers if you don't watch the volume level. From the musical point of view, the unit is definitely a lot of fun, but it is not really capable of generating the more complex sounds that a musician might expect. The attack and decay isn't quite true to form, altering the pitch of sounds rather than the amplitude (volume), which is a little naughty, and not the way a true music synthesiser works. Similarly, the manner in which the wave forms are manipulated by the envelope is interesting, but not really conducive to really first rate music synthesis. To be perfectly fair, the unit is sold and described as a sound synthesiser, and for the purpose of experimenting and generating interesting sounds (which may be incorporated into your own software), the package represents good value and is well supported by the Music Designer software. If tuneful and more complex sounds are your goal, the Dk'Tronics package could prove a bit of a let down. However, if you are thoroughly bored with the possibilities of BEEP, and want to go a stage further in computer sound generation, the facilities offered by the sound Synthesiser will allow you into the same league as BBC and Amstrad owners. If you really want to be a computer musician, then there's probably not much of an alternative to lashing out on a Commodore 64, which contains a very smart custom sound chip by the name of SID!

The DK'Tronics Sound Generator interface, hiding a three-channel sound chip aided and abetted by what appears to be a converted car speaker....

The title screen from the Sound Generator's musical software. Plug a joystick in and drive the cursor around to assemble your tune.

ZX Computing

DK'Tronics £29.95 These have a built-in sound generating chip, usually of the AY type and offer three channels of programmable sounds for music or effects. Separate speaker and interface, AY-3-8912 chip. Good software program to use as a three track recorder supplied with the unit. Takes a bit of time to get used to but produces very effective sounds.

Sinclair User

MORE FROM DK STABLE As one of the oldest suppliers of add-ons for the Sinclair market, DK'tronics has built up a reputation for good, basic, hardware. The latest additions to its range for the Spectrum - two joystick interfaces, a printer interface and a sound generator - do not break any new ground but are well designed and constructed. All use a new, restyled, case which can be used with the Spectrum Plus and should also fit most full-sized keyboards. In addition, three of the four items have through connectors - a welcome change. The less expensive joystick interface is Kempston/Sinclair compatible. It has two standard joystick sockets on the top, the left Kempston and the right Sinclair - keys 6, 7, 8, 9 and 0 for fire. Priced at £13 it should prove popular with arcade fanatics. It does not have a through connector, and thus must be the last add-on attached. For those who need a wider choice of keys the programmable interface at £22.95 could be the answer. It can be programmed using the tape provided or, when a game is running, via a switch on the top. The tape allows you to program any of the keys, including Shift and Enter, and to read two or more keys at once, so you can move diagonally and fire at the same time. The printer interface is disappointing. It can drive any Centronics printer but it has disadvantages which make it a doubtful buy. The software tape provided has two pieces of code on it, one for Epson compatibles and the other for the MCP 40. The Epson code is only 520 bytes long and redirects LPRINT and LLIST to the printer. A copy routine is included but only in one size and, when tested on an Epson printer, appeared to give a line feed which was out by 1/72in. The bottom two lines of the screen are not copied. The MCP code is 680 bytes long and includes a half-sized copy option as well as supporting the INK command. For MCP 40 users the interface might well be a good buy at £39.95 but Epson or Seikosha users who want to use COPY should look carefully before buying. The Sound Generator, priced £29.95, is based around the ever popular AY-3-8912 chip and includes a built-in amplifier and external speaker; it also amplifies the BEEP. The problem with this chip is that it is not one of the easiest to program, although thorough instructions are included that show you how to do this in Basic or code. To overcome that, software is included on tape which allows you to write a tune in three-part harmony and replay it. You cannot alter the length of note - you have to enter two notes to double the length - nor edit a voice once it is entered; you are limited to 256 notes per voice. The chip has 15 envelopes built in and a different one, and/or noise, can be assigned to each voice. That, again, is rather basic and reflects the age of the chip. Although the chip is well known the problem has always been lack of support from software writers. DK'tronics is well placed to change this and some future releases will contain routines to drive the generator.

ZX Computing

Ray Elder

MUSIC MICRO PLEASE! An outline of some of the more harmonious programs and devices recently produced. Ray Elder takes up the Baton and conducts the investigation. For the professional/dedicated/expert musician there is the Midi interface and synthesiser system, but for many others, including yours truly, the cost of such equipment is beyond the realms of an overdraft. For us interested but impoverished would be musicians there are a few more affordable, though much less versatile, alternatives. FORTE! An essential first step is to do something about the BEEP, there are several ways around this, you can simply amplify the thing or, if you want to get the most from the computer, then you will need to purchase a unit which incorporates a sound chip. Most of these units use a version of the AY-3-8910/8912 chip and this is a well tested and reliable chip which can produce some impressive sounds. Simple amplification of the BEEP can be achieved in several ways and is the least expensive of the two options. Beep amps either have a built in speaker or send the sound to the TV and some such units are: THE CHEETAH BEEP AMP, this puts the sound through the TV and is in the same size box as their other units, complete with a full through port for other peripherals. Cost £9.95. CURRAH MICRO SPEECH unit. This is primarily a speech unit but it also routes the Spectrum Beep through the TV and is worth considering if you want to investigate the world of speech as well. Cost £29.95. DK'TRONICS BEEP AUDIO AMP. This is a self contained unit in two parts, the amplifier interface and a separate 1" pod mounted loudspeaker. The interface has a full through port and, although lipped, fits both versions of the Spectrum securely. Cost £14.95. THE TRICHORD, a full sound box including AY chip, amp and speaker and software for both ZX81 and Spectrum, available from Newtech Developments Ltd. Cost ranges from £24.95 to £26.95 depending on model and internal amp fitted or not. WILLIAM STUART SYSTEMS sound generator unit, designed to go with their speech recognition and synthesiser units but can be used on its own (if plugged into a stereo system it sounds superb). Software is available separately and is excellent, the ARP program kept me fascinated for hours. FULLER (reinstated by Nordic) have a sound unit and a master unit which includes speech, we have not tried one out yet, but the new look packaging is nice. And finally DK'TRONICS again, identical to their beep amp in size and shape is a full Sound Synthesiser. This is based on the AY chip and is supplied with a demo tape. Cost £29.95. THE DK'TRONICS 3 CHANNEL SOUND UNIT I will give a detailed account of this unit as it is one of the few still left in my possession, most of the others had to be returned after each specific review, and anyway its one of the latest on the market, and most are similar in operation. This is supplied with an eight page booklet which gives setting up details, the volume is adjustable by a small screwdriver through a little hole in the top of the unit, full volume is loud enough for most purposes! Some demo programs are given which explain the basics of programming the beast, these are in BASIC but a machine code programmer can glean enough information to enable him/her to incorporate routines in their programs. Most of the manual is dedicated to operating instructions for the program supplied, these are brief and there are gaps which left me confused - the use of the Envelope generator for instance. The software itself is good and allows you to create tunes in 3 part harmony and is cursor controlled, this means that it can be operated by a joystick. However I found it a little tedious to use and the editing is almost non-existent, an error early on means re-entry of the rest of the line. During playback the three lines of music are shown as a letter/number representing note and octave. Without prior musical knowledge you may find it hard to get anything of worth from it. The sound quality itself is very good, the speaker handles the output with minimal distortion and many a long hour was happily spent with this program. A unit which is nicely made, looks and sounds good and is well worth considering. It also works well with other peripherals, the Technology Research Disk drive unit functioned without problems and it was easy to convert the software supplied to disk. The ZXLprint III Centronics unit also sat at the back quite happily, and of course DK's own units, joystick interface etc. proved compatible. MAKE MUSIC is a program produced by the Buffer micro shop which works in conjunction with any Spectrum sound unit using the AY-3-8912 chip and attempts to emulate a three track recorder, similar to the BBC Music Processor program. It is quite successful although rather awkward to operate, the screen display is not as informative as the BBC, and envelope control is non existent. Good, but not as versatile as it could have been, and as far as I know, the only one of its type for the Spectrum. XOR from a company called Xorsoft and described by reviewer Clive Smith as "one of the better ones" and Music Maker from Malan are two programs which help you compose simple tunes with the inbuilt Beep. Music Maker from Bellflower is an early attempt which didn't quite come up to scratch, editing and printer copies are virtually non-existent and there are irritating pauses when a new line is needed. Sinclair's own offering is Musicmaster. When it came out I said that it probably pushed this aspect of Spectrum computing to the limit and it remains a top program in this field. This has two modes of entry, note names and keyboard simulated, editing is good, replay is fast and a stave printout is provided. AND FINALLY... from a small company (you may like to play "spot the advert" for their products) comes my favourite program so far! MUSIC TYPEWRITER from Romantic Robot, [redacted] is a very professional piece of programming, easy to use, excellent screen presentation, error trapping and helpful prompts. Fast replay, versatile editing, stave and note printouts, transposing to other keys, six octaves, treble and bass clefs, 23-255MM (metronome scale), menu driven and up to 16 pieces of music held in memory at one time. Even without an amp it sounds good. Do you get the impression I'm impressed? A keyboard overlay is provided and versions of the program are available for use with a sound generator chip and even with the Midi interface if you so require. If you are interested in music and own a computer then get it. Cost £9.95. For those of you who enjoy DIY then watch out for our Beep amp hardware project and some musical programs soon to be published in ZX Computing.