Vesta-Fire DEX-810 Driving Exciter
An unusual beast, this offering from the Vesta-Fire stable is not for increasing the heart rate whilst travelling at speed. No, it is intended more for stimulating the ear than the heart. The DEX-810's closest living relative is probably the Aphex Aural Exciter - Type B (reviewed in Home Studio Recording April '84 issue) although the family resemblance is not reflected in its price which is about half that of the Aphex model. I am not sure how apt the word 'Driving' is in the name but I suspect the main concern for Vesta-Fire was to avoid the word 'Aural' as, by common usage the term 'Aural Exciter' has become associated with Aphex.
The Driving Exciter can be used effectively to make a particular track stand out in a mix. A vocal line, for example, can become more intelligible without unnecessarily increasing its level over a backing track, or a solo line can be made to rise above its accompaniment level without becoming measurably louder. A sound treated by this unit will move to the foreground and show an increase in 'presence' without a significant increase in level. This effect is highly repeatable and simple to set up on the Exciter by the adjustment of just three controls per channel. The DEX-810 is in fact a pair of individual Exciters housed in the usual 1U high, 19 inch rack-mountable case and each channel is available independently offering a pair of mono effects or a single stereo one.
The controls corresponding to each channel are Drive, Freq and Mix. The level of Drive or input gain is set up with reference to a pair of LEDs adjacent to the Drive control. The lower green LED lights to show good signal level and the red to indicate overload, although a little bit of occasional red flashing is acceptable. If the Drive level, however, is set too high the red LED stays alight permanently and the green one is extinguished. By this time there is no need to be watching the indicators as the distortion is obvious to the ears. The working dynamic range is, however, perfectly capable of encompassing typical rock, pop and jingle signal ranges.
The FREQ control appears to act as a high pass filter. As it is rotated clockwise the effect appears to act on a progressively narrower band of frequencies as the bottom rolls off. This offers a certain degree of tuning of the effect. It also effects the overall level of the signal shown by the LEDs and should, therefore, be used in conjunction with the Drive control.
Mix is used to control the amount of effect added to the original signal. In practice, best effects were gained with this knob always within the first third of its rotation when using it in line or patched into an insert point on the mixer. When the device is fed by an effect or auxiliary send, however, and brought back via a spare channel or effects return on the mixer, the Mix control is best used at its 'full on' position. If this is not done when using the Exciter as an outboard effect then the returning signal will also contain a degree of the original signal and thus defeat the object of the unit which is to raise the apparent level of a sound without increasing its actual level.
Between the set of controls for each channel is a Bypass push on/off switch with its associated red LED. This is a very necessary feature on a subtle effect such as this, as the ear quickly becomes adjusted to the treated signal and needs a frequent reminder of the original sound in A/B (original/treated signal) comparison to arrive at the optimum degree of effect. Finally, the mains on/off push switch and LED are at the far right hand side of the front panel.
A pair of standard quarter inch jack sockets for each channel are situated on the rear panel. Each output socket is accompanied by an output level slide switch offering 0dB or -10dB options, the latter being the most suitable for home recording equipment. The mains lead is permanent and the fuse socket takes a 500 mA fuse. Removal of the lid reveals a very neat and simple layout with all ICs socket-mounted.
First impressions of the Driving Exciter in use are adversely affected by a tendency to overdo the Mix control. This gives the impression of a very 'toppy' sound which has a tiresome effect on the ears. After the initial over-enthusiasm has died down and the degree of added effect is cut back to what it should be (which is quite small) useful alterations to the sound can be heard and appreciated.
Using a little excitement on the vocal track in a jingle gave the words extra clarity immediately, without resorting to fiddling with a graphic equaliser as would have been the usual first line of attack on a slightly lifeless vocal. Apart from the Exciter's major usefulness on vocals it seemed to benefit all instruments I tried it on. Bearing in mind, of course, that one does not always require each instrument to stand out on its own.
Where highlighting is required this Vesta-Fire unit is a source of instant presence which is more or less guaranteed and repeatable. It is especially useful in recording that notorious bane of the recording engineers life, the acoustic guitar, so satisfying to get right yet often so fiddly. The DEX-810 seems able to pick out and enhance that sparkle that can be so tricky to find.
Very small amounts of excitement added to a complex mix can give a subtle definition to various aspects of the overall sound. For instance, one piece of music contained one of those big snare drum back-beat sounds - when added to the overall stereo mix the repeat echoes on the snare become almost individually perceptible, whereas before they had just merged into a big, fat sound.
Resolving to this degree of detail may not always be desirable, but there will be cases when it can be used to great effect. Adding excitement to any recorded signal can aggravate any hiss or noise already present. On individual tracks, however, this was only really noticeable in isolation and, in context, was masked by the rest of the mix. Also, when exciting a complete final mix, less effect is generally desirable anyway and in this case any adverse effect on hiss or noise was only apparent after the piece was over, when no musical signal was present.
I found the precise nature of the Driving Exciter very intriguing - a sort of hybrid equaliser operating in the 3kHz presence region coupled with frequency conscious compression.
A single note from a synth at 0dB on the VU meter gave only a faint rise of the needle when the Driving Exciter was switched in, although the ears heard a definite increase in level which should have equated with a reading of plus 2 or 3 dB. This effect was also bourne out by some rather more sophisticated test equipment than a VU meter. I attempted to match the effect of the Exciter with a graphic equaliser by ear. Analysis on an oscilloscope showed that I had got quite close to the waveform and final adjustments were made whilst watching the dual trace on the scope. Complete matching, however, proved impossible. There was something occurring at the high end of the trace that could not be achieved on the graphic alone and I do not think a parametric could have matched it either. The most interesting pointer toward the DEX-810 being considerably more than some sort of fancy equaliser was that the signal levels from the equaliser and the Exciter, although both sounding similar, measured significantly lower from the Exciter.
At the time of writing, the Vesta-Fire DEX-810 Driving Exciter has only been in the country for a couple of weeks and a book of words has yet to be written for it. When it is, however, it may tell you that an increase in apparent loudness from your tapes is possible before tape saturation occurs. It would also be interesting to hear if it will increase the apparent loudness of records on the radio (or do they already use a version of this technique anyway?). One more point. Could it help to overcome that problem with small PAs of getting the vocal out over the top of everything else without feedback?
As regards the Driving Exciter's use in the home studio, I would not place its importance above that of owning a good digital delay unit and compressor, but if these things have already been ticked off on your list of purchases for your studio and you are in the market for a bit of luxury, which at worst can give your tracks instant presence without messing and at best add that extra attention grabber to your production that could make you famous. I should try a bit of Driving Excitement.
Acknowledgement to Jeremy Saltmarsh for technical assistance.
The Vesta-Fire DEX-810 Driving Exciter retails at £213 inc VAT.
Details from: MTR Ford House, (Contact Details).
Review by Martin Sheehan
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