CLARES' ARMADEUS

Stuart Bell takes a look at this new sound sampling package from Clares.

Armadeus (Wolfgang Amadeus Mozart - get it?) is the name given by Clares both to the software and the sound sampler podule which together form the Armadeus package. The software will operate with other hardware, namely the Armadillo A448 and A448b boards, the Wild Vision 1208, and the Unilab Computer Interface - the latter being interfaced using the Acorn I/O podule - but for this review, the podule and software were tested in tandem.

A sound sampler captures analogue signals - such as music from a hi-fi system - measures the waveform many times a second (at what is termed the sampling rate) and converts that measurement into a digital value which may then be stored in the host computer's memory. Playback requires a reversal of that process, with the digital values stored in memory being converted into an analogue waveform which is sent to the Arc's internal speaker, headphone socket, or, in the case of Armadeus, to the 'line out' on the podule.

The performance of such samplers is measured by two criteria. Firstly, the resolution of the conversion. This is the number of discrete levels which can be detected by the sampler. The Armadeus podule, like most others, works to 8-bit resolution, giving 256 levels. The higher the resolution, the lower the noise introduced during reply as a result of the discrete levels used during the sampling, but also the higher the cost. The second parameter is the sampling rate - the number of samples taken every second. For a rate of n samples a second, frequencies up to n/2 Hz can be sampled. Furthermore, frequencies above this level must be supressed, otherwise they will add disastrous distortion to the signal. Clearly, the higher the sampling rate the better, but also the more memory required. Additionally of course, the hardware imposes limits on both parameters.

THE HARDWARE

The Armadeus podule (bearing a Wild Vision copyright notice) is half width and provides external connections for 'line in', 'mic in' and 'line out'. The board is well-made, neatly laid out, and can be fitted in a few minutes following the instructions provided - assuming, of course, that you have a backplane installed. A blanking plate is supplied should you need this, as are two spacers which correct a problem with the backplane positioning on the 300 series. Connections are by 'phono' (line) and standard quarter-inch jack sockets. The board's input gain may be adjusted under software control, thus allowing a range of input levels to be sampled properly - a feature not found on many sound samplers. Another facility offered by the hardware is a digital to analogue output. This allows sounds to be replayed through the podule at a higher quality than could be obtained using the internal sound system.

THE SOFTWARE

If the system only allowed the re-playing of recorded signals, then its value would be very limited. However, the Armadeus software provides a very powerful suite of tools with which to analyse, modify and store sampled sounds.

Once a sound - such as a note from a musical instrument, spoken words, or even a line of a song - has been sampled, its waveform may be displayed and then modified. Sections may be marked, moved, repeated, deleted, faded in or out, or changed in pitch. This is accomplished using an oscilloscope-like display which allows the horizontal scale to be increased progressively so that the most detailed part of the waveform may be examined. Echo may be added, and looping points indicated, to control the repetition of parts of the sound. Samples may be concatenated or overlaid by an interface to the file system which fully meets RISC OS standards - for example to load a file, its icon is dragged from a directory viewer into the main Armadeus window. Indeed, the whole package, from first being installed on the Desktop icon bar, follows the RISC OS standard Wimp environment, and all options are made available through hierarchical menus.

A couple of very nice features are the VU meter and the FFT (Fast Fourier Transform) analysis. The first one of these provides a real time image of the sound as it is sampled or replayed, and is much the same as would be seen if the signal was examined using an oscilloscope. The FFT on the other hand uses a mathematical technique to convert the sampled image into a frequency versus amplitude display. This allows you to see how the tones making up the sound are distributed through the frequency spectrum, and as such, performs much the same function as a spectrum analyser. Neither of these features work within the Desktop environment. Instead, the screen mode is changed and the display produced in real time. However, as soon as the operation is complete you are returned to the Desktop exactly where you left off.

DOCUMENTATION

The facilities offered by Armadeus are described in a well-produced A5-size spiral bound manual of 70 pages which combines the usually separate tutorial and reference sections by suggesting exercises to be followed after new material is introduced. These exercises make use of the two discs full of ready-sampled sounds which are supplied with the program disc. None of the discs is copy-protected, so hard-disc users should have no problems. Three cheers for Clares' trusting attitude: let's hope Arc users don't abuse it.

UNDER TEST

The software does all that the manual claims, and provides a very easily used range of tools with some very impressive displays. Connecting my CD-player playing a Chris de Burgh album revealed that a sampling rate of about 15kHz produces adequate quality output, whereas 10kHz made the artist sound as if he had a lisp! My 1Mbyte 310 allowed a sound buffer of about 500Kbyte (the package includes an Application to maximise this), allowing just over 30 seconds' recording at 15KHz. Attempts to playback through the Armadeus 'line out' and a hi-fi system revealed the most annoying aspect of the whole system. Whereas internal output can be achieved by hitting one function key, external output requires a menu selection and confirmation every time. Since the manual goes into raptures about the superb quality obtainable from the Armadeus output, when one is repeatedly testing minor modifications to a sample this becomes increasingly exasperating.

APPLICATIONS

What, you may ask, does one do with the samples thus obtained and manipulated? The package provides a utility to save a sound as a module, so that it can, for example, be played whenever Control-G (normally the 'bell' sound) is typed, or, more usefully, used in applications such as 'Maestro'. A Readme file on the systems disc warns users that samples to be made into modules should be re-sampled at 48usec (just over 20kHz), to avoid problems of pitch. I did this, but still ended up with Chris de Burgh sometimes sounding just right, but at others as a barely audible boy soprano, depending on how the same module was being used. I suspect that the presence of the Readme file indicates a problem which has not really been fully solved. I think that Clares really must make the process of producing sound modules which play at the correct pitch much less of a trial-and-error process.

The answer to the question 'What do you use a sound sampler package for?' is fundamental to the success of this product. Armadeus is not really an end-user's product, unlike a word-processor for instance. It is a "means to an end" rather than an end in itself. For those wishing to generate sound effects for use in programs - especially games - or musical tones for use in music packages, then Armadeus will meet their requirements most effectively. Some scientists, educationalists, or medical physicists will find its ability to act as a storage oscilloscope at audio frequencies, with level-measuring and frequency-analysis tools, most useful, and it may find a 'niche-market' in those areas. Such users, however, will almost certainly require better hardware documentation (none is currently provided), and some low-level driving software, if they are to produce specialised applications for the Armadeus podule.

The manual concludes its answer to 'What can you use it for?' with 'most importantly it is just great fun.' That is indisputable. If Clares address the issues of the ease of obtaining external output, and the pitch problems with sound modules, then the Armadeus package will be an excellent mono-phonic high-speed 8-¦bit sound sampler, driven by a superb piece of software. However, unless you have a specific application in mind, then at £200, it may seem rather self-indulgent for some 'great fun'.
ProductArmadeus sound sampler
SupplierClares Micro Supplies,
 98 Middlewich Road,
 Rudheath, Northwich,
 Cheshire CW9 7DA.
 Tel. (0606) 48512
Price£79.95 (Software only)
 £149.95 (Hardware only)
 £199.95 (Both together)
 (All prices inc. VAT)