Supplier: William Stuart Systems or Commotion
Price: £49.95 and also requires Chatterbox module or WSS I/O port.

Big ears is a CB term for operators who listen to conversations which don't concern them. Nothing could better describe the speech recognition package from William Stuart Systems.

The package contains the SRI speech recognition unit with connector DIN cable, a battery powered microphone and a demonstration program.

Speak into the microphone, teach Big Ears various words, and it can learn to recognise them.

Big Ears connects to the Spectrum by either the WSS Chatterbox speech synthesiser or the WSS I/O (input/output) port - a review of the latter is included elsewhere in this feature.

Big Ears only stores and recognises one word at a time and holds a maximum of six on a 48K Spectrum. First, give the word a number by which it can be identified in the Big Ears Ram dictionary and spell your chosen word. Once you've done that the program prompts you to press Enter and speak the word into the microphone.

When you press Enter you'll have approximately five seconds to speak the word.

Big Ears takes four samples of your voice of each word and translates each sample into a voice print which is an array of 36 numbers. The computer takes several samples of your voice saying the same word because, just as everybody has a different voice, so your voice is slightly different in level and inflection every time you say the same word.

The four computer voice prints are averaged to give a range of levels and inflections at which you might say a specific word.

The result is not always accurate. You may, for instance, want the computer to recognise the word 'science' but it keeps comparing it with 'psychology' which Big Ears has also learned. The reason is that you - and most other people - pronounce 'psy' and 'sci' in a similar way. Big Ears has no real auditory sense and. If there are several like - sounding syllables in certain words it has learnt it will get confused and maybe respond with the wrong word.

When you've taught the computer two or more words you can Test and Demonstrate speech recognition Type T, for Test, if you want to see the calculations which the system does to match your word with one in its dictionary. Speak into the microphone when prompted by the program and the correct dictionary entry should be displayed on the screen with a voice print and correlation table.

The Demonstration option is similar to Test.

Big Ears can make your computer seem intelligent.

Chatterbox can respond vocally to your spoken commands into Big Ears. Alternatively, you could use the package to control robots with spoken commands through the I/O port. For instance, you could teach Big Ears 'left' and 'right' and write a Basic program to link those words to the movement of a floor turtle or similar robot.

Instead of typing in the word which corresponds to your spoken word you could type in a reply to a command.

For instance your spoken word could be 'up' to make a mechanical arm move up. The reply could be 'your command is being obeyed'. Type in the reply and teach the computer the word.

The Big Ears control program was written in Basic so that you can alter it, add extra lines, change the number of words the dictionary holds and pull out options that you may not require in your programs. The speech routines, however, are fully machine-coded. Instructions on how to customise the program and add routines are given in the short booklet which accompanies the package. It also includes line-by-line details of the control program so that you can adapt it to bring other devices, such as robots, security systems, or even the infamous Red Box at your beckoned call. Both Big Ears interfaces are open-ended so you can add whichever devices you require on to the back of your Spectrum and control them through the machine's ports.

For the majority of Spectrum owners, Big Ears is an expensive show-off rather than a practical show piece. It has an irritating habit of picking up background noise making it useless in any environment other than a padded cell. If you are, however, desperately seeking new things for your Spectrum, Big Ears will keep your interest for a couple of hours at least.

ADDING ON YOUR SPECTRUM

Our review team take a brief look at some of the hardware add-ons fir the ZX Spectrum.

Now that the ZX Spectrum has well and truly established itself on the micro market, it is amply supported by a wealth of hardware add-ons. Most of these peripheral devices have been manufactured by the people who supported the ZX81, but just as the Spectrum has attracted new users with its prowess, so too has it attracted a new following from the add-on manufacturers.

In this brief guide, we have not tried to cover all the devices currently available on the market but rather give you a flavour of the technology you can add on to your Spectrum. As joysticks are an obvious favourite, these have been covered in some detail whereas RAM packs are fairly standard and so have only been briefly touched on. Also included in this section area number of quite specialised add-ons like sound units and a digital tracer.

If you own a Spectrum, you will no doubt have begun to realise the potential you hold in your hands. Over the next few pages you will hopefully see further applications for you and your computer to explore.

Originally designed for the UK101 and Superboard, the Big Ears speech recognition system is now available for most leading micros including the ZX Spectrum.

Housed in a sturdy box, the Big Ears system consists of a microphone, pre-amplifier, analogue frequency filters and digital interface. You are also supplied with a software package allowing you to become acquainted with what you soon find is a very complex piece of technology. The program with the system has four modes. Learn, Test, Demo or Save. All the modes are fairly self-explanatory, and the demo explains all should you require comprehensive details.

Using the equipment, you can allow the Spectrum to learn a word, you can then test that the computer understands and recognizes that word, and then save the program together with its new expanded vocabulary.

During the review period, we had the Big Ears programmed to recognise nearly everyone's name in the office. And this it did quite successfully, except for the name 'Helen' which it seemed to 'recognize' every time it wasn't quite sure!

Complete with full instructions for use, the Big Ears speech recognition system is priced at £49. For further details of this device, contact William Stuart Systems Ltd, 44 Bedford Gardens, London W8 7EH.