We conclude our two-part review of Tantek's Tanrak system of signal processing units, with the promise of yet more modules to come in the near future.

Dynamic Noise Filter 2

Noise is the studio's public enemy number one. One day, of course, all studios and recordings will be digital and quantisation will be numero uno but until then - and until small studios can afford it - we're stuck with analogue signals and noise.

The Noise Gate can help in certain areas, the Compressor and Limiter can help in others. A good noise reduction system is a help all round, but what about recordings you made before you could afford all these goodies?

The Dynamic Noise Filter could be the answer. It's basically a low-pass filter whose cutoff frequency rises when presented with high-frequency signals above a certain level - a similar idea in principle to a reverse compressor. When high-frequency signals are present they tend to mask the noise; when they drop, the unit cuts down on the noise level.

I thought this was too good to be true, but it does work. You can leave the unit permanently patched in to the end of the recording chain, or you can process incoming signals through it. All this is possible in stereo, too.

An LED shows when the unit is filtering, and the Threshold control needs to be adjusted carefully to find the optimum level for the signal; if you set it too severe, glitches can occur as it clamps down on noise during quiet sections.

The device works better on some material than others. If you can hear noise in a piece containing high frequencies, you're pretty much stuck with it unless you resort to filtering.

I used the Filter to clean up some old recordings and threw in a bit of Enhancing (see next unit), too. It won't remove every trace of noise in a piece, but it can reduce it and it is difficult to tell if the signal proper has been tampered with.

Really noisy pieces tend to be the product of much bouncing, and the Filter can help tidy them up if, like me, you're a messy bouncer.

Psychoacoustic Enhancer

Bit of a weird one, this. When the first such enhancer hit the market some years ago at around £1000, it was very much a black box. Listeners agreed it did something to the sound, but no one could quite say what. Research has since opened the box (and took the money) and there are now several budget enhancers on the market.

Tantek thoughtfully tell us how their Enhancer works: it's a mixture of high-frequency boost, compression and harmonic generation. You can hear the HF boost even on so simple a sound as a flute, but is there something else there as well?

Well, sound is all about subtleties, and never is this more true than in the use of the Enhancer. The controls must be set carefully, as you soon learn that it's possible to enhance noise, too. The manual says there is an optimum setting for every situation, but finding it is the trick, as adjusting one control usually affects the others as well.

The Enhancer is particularly useful for giving tired recordings a new lease of interest; the sort of mixes which have been EQ'd and bounced so many times, they sound like rubber cheques. You can place the device anywhere in the recording chain; in a mixer's send and return channel, or direct to instruments as they are being recorded. Plug a drum unit into it, vocals, a synth. Basically, you can enhance anything.

The Psychoacoustic Enhancer works with mono signals only; you need two to process a stereo signal.

Parametric Equaliser

Every recording setup needs good EQ facilities. They should be at the top of your shopping list - after a mixer, a tape machine, and a mic. A Parametric EQ allows you to select a certain frequency, and then cut or boost it. It can emphasise the kick of a drum, control the ring of a cymbal, or trim the sizzle out of a string sound. The dividing line between using EQ for corrective and creative purposes is very thin. My line vanished years ago, so now I just EQ a sound until it sounds right. If you're a purist, slap my wrists.

The Tanrak Parametric covers an impressive frequency range from 3Hz to 37kHz, with cut and boost ranging from ±10dB at high bandwidths, to ±30dB with narrow bandwidths. The figures are automatically optimised by clever circuitry.

A neat unit and a worthwhile addition to the rack, though if your mixer already has comprehensive EQ facilities, you may not consider it as important as some of the other Tanrak modules.

Digital Sampler-Delay

Well, this is the biggy. It's twice as wide as the other modules, and has twice as many controls. The audio signal is not patched into it directly; you must go round the back and do that yourself. It also has Gate In, Modulation In and CV sockets.

At full 15kHz bandwidth, the Delay/Sample time ranges from 15mS to 1.4 sec. This range can be raised from 90mS to 8 sec with reduced bandwidth. The Length control sets the time and the Trim control fine-tunes it, reducing the bandwidth at the same time. Lower bandwidth settings are reflected in the reduced quality of the echoes, and it's a loss that can become quite noticeable, especially with many repeats when the Regeneration control (feedback) is turned up.

The usual impressive, useful and interesting delay effects can be produced - along with some pretty horrible sounds if you twiddle the knobs (in)correctly. You can plug in the Modulation Oscillator for vibrato effects or just to add something extra to the delay, so long as you're careful that the modulation doesn't cause distortion. Increasing the Trim helps combat this, but at the expense of reduced bandwidth. The Mix controls the balance between the dry and processed signal.

Sampling is easy. Set the sample time and play the sound. The unit triggers automatically (though you have the option to apply an external trigger) so split-second finger movements are not required.

A sample is played by pressing the trigger button, applying an external trigger or by a signal at the audio input. The CV input is calibrated to accept a 1V/octave signal from an analogue synth, and a Tune preset can be adjusted to scale the keyboard if required. This allows the sample to be triggered by almost anything, so long as it has compatible CV and Gate sockets on the back.

The Start control lets you skip any unwanted bits at the beginning of the sample; they can appear at the end, but the Length control can then be used to shorten the length of the sound. The Decay control helps extend a sample with an abrupt finish, and is most effective during looping, as it controls the rate of decay of the loop.

Looping, however, is something you should contemplate only if it's absolutely essential. It can take a while to find a suitable looping point and some sounds, of course, insist on glitching no matter what you do. In the (admittedly limited) time I spent with the Tanrak, I never managed to produce a loop which didn't glitch at all, but I came close. The loop only plays when it is retriggered, and every time it's gated a length of sample at zero memory is played, so the initial attack of the recorded sound is preserved.

An Overdub button allows you to mix the existing sample with a new one using the Regeneration control. You can build up new sounds and effects quite easily this way, and I succeeded in putting together my own orchestral stab from a variety of motley sources. It weren't 'alf bad.

You can store different samples in different parts of the memory by using the editing controls to select start and finishing positions. At full bandwidth this doesn't give you much time to play with, and as you increase the time you reduce the quality. Situation normal.

Finally, you can save and load samples to and from tape just as you record and play a sample into the unit.

All in all, this is a super module that really is fun to use. It does produce some background noise, though, which seems to be par for the course for an eight-bit companding system these days. My guess is that, with noise at its present level, the Tantek sampler wouldn't meet a professional studio's demands. Whether or not it falls short of yours only you can say, but it's worth remembering (a) that this sampling delay really is incredibly cheap, and (b) that since I tested the Tanrak, the designers claim to have redesigned the circuitry so that noise levels are now reduced by about 10dB.

The Other Modules

Yes, there are more. The Phantom Power module, a Multi-Delay module, a Mixer module and a Panner-Fader. I didn't have any of these to review, but they must be mentioned for the sake of completeness, and I have no reason to doubt that they're built to the same standard as the other Tanrak modules. Tantek are aiming to produce a new module every two months, so buyers have plenty to look forward to, including - and this is a piece of hot news - a MIDI-to-CV converter.

Most of the Tanrak units can be used with stereo signals, and although I suspect many home users will tend to record in mono and create their stereo image after (or during) much mixing, there are many applications suited to stereo processing - in these cases the Tanrak won't let you down, though be warned that you may have to reconfigure your patches and some of the modules. The flexibility is there, and it must be welcomed and applauded.

Conclusions

The Tanrak system was developed and designed for the home and semi-pro studio, a market that always has one eye on the price-tag and is keen to appreciate value for money. Well, Tanrak must get 10 out of 10 for value. If you buy the kits, make that 11 out of 10.

Let me put it like this. If I were just starting my studio, Tanrak would be on my shopping list, and probably somewhere near the top. But then, if I hadn't seen the competition, I wouldn't know what a bargain I was getting. At the very, very least, send for details of the Tanrak modules and if you don't buy them, let me know which system you found to be superior.

I was born too soon.