This month Nobby Line continues his look at the home-recording 8-track package we put together around the TASCAM 38 8-track recorder and M-35 Mixer. Signal processors from U.K. manufacturers REBIS were the type we chose — Nobby checks them out.

RA202 De-esser

The vocal is the centre point of most songs, and achieving the desired sound, which will probably include warmth, sparkle and presence, generally requires the use of compression and equalisation, especially in higher frequency bands. But this can cause undesirably prominent sibilance, and it is the job of the de-esser to soften their effect by means of selective compression.

The RA202 is triggered either when the level of the 5kHz to 20kHz frequency band exceeds the preset threshold, or when it rises above the level of the 20Hz to 5kHz band. The threshold is continuously variable and along with a bypass switch, it's the only control on the module, making operation extremely simple. When triggered, it compresses across the whole frequency spectrum to ensure that the lower frequency wind noise peaks usually associated with sibilance problems are also removed. As with any such device, over-doing it in an attempt to save a really badly sibilant vocal results in a squashed, squawky sound, but used moderately, it was very effective.

RA200 Pan System

Those of you who've been affording this series avid attention over the past eight or nine months will know that the position of a mono source in a 2-channel stereo image is a function of its relative levels. In other words if it is fed equally to each speaker, the apparent origin of the source will be mid-way between them, and by gradually increasing the relative level in the left-hand channel, the image will shift to the left, and vice versa. The pan system allows various, and sometimes complex, image changes to be executed automatically.

The system I used achieved this by means of a dual VCA module — RA216 — (voltage controlled amplifiers) and a controller module RA215. This set up allowed me to (a) pan a mono source, (b) crossfade between two mono sources, (c) alter the left and right balance of a stereo source or (d) fade a stereo source.

These are just the basic functions, and there are switches and buttons which allow you to divide the space between the speakers into four and, at the touch of a button, move to the next programmed point and stop, or move the image to and fro between either left or right and centre. The rate of all these cycles is continuously controllable from a tremelo-like 10 cycles/second to an almost imperceptible 1 cycle/minute.

The creative limits of this system are largely down to the operator, and the list of possibilities is endless, especially if you buy a second dual VCA module, in which case stereo crossfades and image reversals can be simply executed. Among many other effects, I used function (a) in the tape echo, to have the repeats flying across the image, function (b) continuously to crossfade between two picked acoustics playing the same chord sequence with different inversions, (c) I didn't find all that useful, but it was quite effective in shifting the image of a double tracked instrument, and (d) allowed the rehearsal of a smooth fade at the end of a mix. There's also an input for an external modulating voltage to control the pan/fade rate, and in combination with other effects, the scope is considerably widened.

It's somewhat of a luxury compared with the other Rebis units, but still a very useful tool to have in the rack.

RA206 Oscillator

A valuable but fairly inexpensive module producing a sinewave with continuously variable gain up to +22dBm into 600ohms, at 14 fixed frequencies between 20Hz and 20kHz. Indispensable for alignment of machines, tracing faults or for checking the balance of a stereo pair of channels on your desk, etc.

Distortion is low and accuracy high and, although a unit with a continuously variable frequency might be more flexible, such a device with comparable accuracy and purity would cost considerably more.

RA200 Delay System

Considering the wide range of effects offered by this system, £552.00 is by no means expensive. It is, however, a fair amount of overtime to be parting with in a single spasm, and you might therefore be encouraged to learn that the system comprises three distinct types of module, which can be bought, and used to good effect, individually. The first module to acquire would be the RA205 analog delay (ADL), two of which are included in the complete system. Each module offers a delay time of between 2 and 40ms with a reasonable frequency response (15ms -2d8 at 20Hz, -Id8 at 15kHz) or 4 to 80ms, which halves the signal to noise ratio and frequency response (30ms, -3d8 at 7kHz). It also provides a direct/delay signal mix, a feedback control and a noise suppression control which gradually applies HF emphasis/de-emphasis, at the cost of reducing the circuit's HF headroom.

Next might come either a second ADL or the RA208 Modulator module, a VCO with rate, depth and offset controls, a choice of sine, triangle and square modulating waveforms, plus switches to invert the phase of either the waveform or the offset.

With the ADL alone you are limited to simple ADT, single repeats up to 80ms, short, multiple repeats up to 80ms and a fairly mild, manual phasing effect caused by slowly changing the delay time of the delayed signal, mixed in with the direct signal. The modulator basically allows the continual, automatic changing of the ADL's delay time according to a square, triangle or sine wave characteristic. The rate is continuously adjustable between 70ms and 40 seconds per cycle, and fast vibrato, phasing and more natural ADT are all easily possible.

The modulator can drive a pair of ADLs, and the addition of a second delay module opens up the possibilities considerably, as the two units can now be used independently, in parallel, in series, or against each other to produce a longer maximum delay time, triple-tracking, much deeper flanging effects as the two delays are swept backwards and forwards past each other, and a whole range of tube, doppler, bounce and echo/reverb effects.

Mixer module RA209 provides the means to perform a variety of mixes and phase inversions between the two ADLs, and allows simple switching between independent, series and parallel operation. It gives a wider range of single path permutations, making more subtle operations possible, quicker and simpler.

The range of weird, powerful effects available from the RA200 series delay system is huge and, if used with other processors, open to continual expansion according to the individual's imagination. For natural delay, echo, reverb and tracking purposes, there is the usual analogue limitation of delay time against quality, however for short delays it is quite usable and produces good ADT, rock and roll (tape) echo and a reasonable electronic reverb, although in this respect it can't compete in terms of a natural sound with even inexpensive spring devices. On the positive side however, just playing around with the system can bring up effects and sounds which inspire different arrangements for recordings, and can be enough to push you out of a musical/sounds rut. It really is great fun to play around with. The only gripe from the practical point of view is that there's no peak overload indication anywhere, on any of the three modules, and with equipment of this type getting the optimum level is of definite importance.

On the whole though, I was extremely impressed with the Rebis range and presentation. It's compact, high quality, good value and, equally importantly, the range of modules is ever expanding. In fact, no, I'm sorry, you can't have it back!

The individual prices of the modules are:- RA205 ADL £224.25 inc VAT, Delay Package £480 plus VAT, RA208 Modulator £81.65 inc VAT, RA209 Mixer — £79.35 inc VAT.

Next month will see us on the home straight for this set-up, in which I'll turn the spotlight on the JBL monitors, the Master Room reverb and the TEAC Tascam Stereo Mastering Machine, auxiliary meter unit, headphone distribution amp and parametric equaliser. Can't wait, can you? Try taking some deep breaths and reading a few back issues to keep you sane in the meantime!