Spring reverberation devices in general have many pros and cons. Furthermore, each different model from each manufacturer has advantages and disadvantages over its competitors in sound and facilities. These differences are more apparent between spring reverbs than between most other types of effect. A digital delay, for instance, will delay a sound for a longer or shorter period with a greater or lesser bandwidth than its competitors. Weighing up these particulars against price, and whether the modulation section works, will often be enough to guide you as to which unit to choose.

Spring reverbs on the other hand are produced subject to the opinions of more than one school of thought: should the majority of the budget go on the springs themselves using ones that are as linear as possible in response, so that what goes in is still recognisable when it comes out? Or should less be spent on the springs and a little more on equalisation circuitry to flatten things out this way? Should the EQ circuitry be optimised within the unit or left user variable? Are limiters necessary to help iron out 'boings' and 'twangs' from percussive sounds or will this be less of a problem with better springs? Indeed, would better springs be more sensitive and so possibly more prone to adverse reaction to percussive thumps and bangs? All this makes choosing a reverb system a problem that requires some thought in order to come up with the best option to suit your own requirements.

Spring Time

Although there are other ways to produce the reverberation effect, spring lines are still the most effective low-cost method to suit the home studio situation and budget. Flutter echo produced by many repeats of a short delay time does not really do the job properly as it tends to sound rather metallic. Another possible solution would be to install a microphone and speaker at opposite ends of the bathroom but this is unlikely to be very practical. Although there is at least one plate reverb that could fall within the budget of the small studio (made by NSF) its size might prove a problem in some home set-ups. Finally, digital reverb could be considered but it is only just becoming affordable and it will be a couple of years yet before it can compete with spring lines on price.

We are left then with spring line reverberation as the most popular choice for home studios, and both the RV-2 and RV-3 are suitable candidates for selection.

RV-2

The Vesta Fire Dual Reverberation device RV-2 has been available for some months now and is a fairly basic, no frills, dual reverb. 'Dual' means it can be used as two completely individual reverb units and can also produce a true stereo output as opposed to the type sometimes referred to as 'pseudo-stereo', whereby a single signal is phase inverted at the second output. This creates a sense of space when these signals are panned left and right in the stereo image but they will cancel each other out and disappear altogether if summed back to mono as, for example, if they were played back on a mono cassette machine.

The RV-2 uses eight springs, four per channel, each of differing length and diameter which helps to further randomise the reflections and so produce a more full reverb sound.

The inputs and outputs for each channel are on the rear of the 2U high 19" wide rack-mountable case and accept standard unbalanced quarter inch jack plugs. The unit is designed to be used primarily in conjunction with set-ups that include a mixer. This is indicated by the lack of controls for mixing dry and reverb signals and also the fact that no equalisation controls are provided. This is the preferred system for multitrack recording provided that the mixer is large enough to allow two channels to be allocated solely for the left and right reverb returns. All the mixing of the reverb signal and any necessary equalisation can then be controlled directly from the mixer.

Having said this, there is a small slide switch located on the rear panel between the input and output sockets which can be switched to allow a fixed level of the dry signal to pass straight to the outputs. This allows in-line use of the unit with a guitar combo, for example, with the mixing in of the desired quantity of reverb signal being affected by the use of the input and output controls on the front panel.

The input level control for each channel is used in conjunction with its respective overload/limiter LED indicator. These are square bi-coloured LEDs which first turn green and then red as the limiter comes into operation. The optimum level for operation being when just the occasional red flash shows. A low cut switch is provided for each channel which puts a 6dB/octave filter into operation below 100 Hz. This can be useful for cleaning up a bass-heavy signal before it reaches the springs in order to prevent unwanted excursions by the springs, for example, on a bass drum. It can also be used to give a lighter effect to the reverb on vocals, although in practice I found the springs to behave quite cleanly at the bottom end and preferred to ease off the bass a little on the mixer EQ to achieve a lighter effect if necessary.

On the far left of the front panel are a pair of illuminated, light touch, push-buttons to switch the reverb in and out on each channel. Each of these switches also has an associated jack socket for footswitch operation. If only one foot-switch is connected to the channel 1 socket it will operate both channels simultaneously. A two position rotary Input Mode switch is used to combine the two inputs in the 'Blend' position or keep them as two independent channels in the 'Dual' position. The 'Blend' position is useful for producing stereo reverb from a mono input which is how this unit will probably most often be used. This is fortunate as there was some degree of high frequency crosstalk between the two channels in dual mode. However, it was only noticed in a strict, worst possible case test and would probably not be noticed under practical operating conditions.

The only remaining feature is a two position output mode switch. This will switch the reverb from channel 1 to the channel 2 output and vice-versa, a little trick which I can see practically no use for when using the RV-2 with a mixer, although in-line it may have occasional special effect use.

Now to the important bit - what does it sound like? The depth of reverb possible from the RV-2 makes you wonder how it can all come from a 19" unit. It is smooth and full and is of a quality that I would have associated with larger springs had the bottom end extended a little further down. The reverb obtained is rich without being too prominent at any particular frequencies and the acid test of percussion on spring lines did not cause any undue problems. Good results were achieved from all types of programme material and background noise was low. All these characteristics point towards the RV-2 being a good home studio device.

RV-3

At the time of writing the Vesta Kozo Dual Reverberation device RV-3 is still a few weeks away from being generally available in this country, so at the time of reading you should just about be able to get hold of them.

The RV-3 differs most obviously from the RV-2 in that it offers more onboard facilities. It is, again, a two channel unit which can be used independently or as a stereo pair from a mono source, selectable via an 'Input Mode' slide switch on the front panel. Above this slide switch is a reverb on/off toggle which serves both channels. It is a shame this facility cannot be footswitch operated as in many other respects the RV-3 lends itself well to use on stage.

Each channel has its own comprehensive level/mixing section. The rotary input level control is used in conjunction with a red limiter LED. This glows progressively brighter as the input signal level is increasingly limited. Although there is no overload indicator provided, it proved difficult to overload the input and ideally the unit is best run without taxing the limiter too fiercely or the quietest passages of a recording are going to produce as much reverb as the loudest parts resulting in a rather unnatural sound. There are also individual output and mix controls for each channel making the RV-3 just as suitable for use in-line as for use with a mixer.

Another feature which makes this a valuable unit for live and smaller studio work is the inclusion of a three band equalisation section on each channel. Some form of EQ is beneficial for in-line use to give independent control over the dry and the treated signals and also for use with smaller mixers when insufficient input channels may be available to dedicate to the reverb return signals. In cases such as this, where the effects returns are unlikely to have EQ sections, their inclusion on the effects unit itself is very useful. The chosen frequencies of 100Hz, 800Hz and 6kHz on the RV-3 proved very successful during tests and offer a wide degree of control over the reverb sound without showing up any obvious inadequacies in the response of the springs.

The quality of the reverb sound itself is not as deep or as wide as the RV-2 due partly to the fact that it uses only half the number of springs. It is, however, clean and free of any nasty prominences and stood up well to the percussion test, aided a little no doubt by its slightly limited frequency range.

In operation, the RV-3 is marvellously noise free and is made even more so by an internal noise gate. It is debatable whether the level of noise the RV-3 produces warrants treatment with a noise gate but commendable that the gate's threshold level is suitably adjusted so as not to interfere with the decay of the reverb. The quiet operation of this unit must be a big plus in the studio, especially for budget multitracking where noise avoidance can become a major occupation!

When using the RV-3 in the 'mix' mode to give a stereo output from a mono source, the channel 1 and 2 outputs were panned hard left and right in the normal way on the mixer and gave a convincing sense of space. However, I noticed a certain loss of high frequencies on panning both reverb channels back to centre. One possible cause for this may be that in the 'mix' mode the phase of the input signal is inverted as it is sent to feed the second channel to achieve a wider effect. This is fine so long as playback is in stereo but rather unfortunate should playback in mono ever be required, as the top end of the reverb will suddenly go missing.

As the RV-3 is a true stereo device anyway, as opposed to pseudo-stereo, I would have thought any extra attempt at enhancement rather unnecessary. Having pointed out this little quirk though, the number of instances where it will occur are likely to be negligible as most playback systems are stereo and if the tapes are mixed for mono in the first place the problem will not arise.

Bouncing Out

Considering the RV-3 is two channels of reverb packed into a 1U, 19 inch case, it produces a very reasonable sound. Its small size, mixing and EQ facilities would be an asset for stage use, but add to that its clean and quiet operation and you have a device that is highly suited to the small studio. It is also remarkably resistant to vibration which can cause nasty crashing sounds all too easily in some units as the springs get jolted around by an inadvertent knock or footstomp on floorboards.

With the RV-2 we have a device built for rather more permanent studio and PA work. Its basic design for use in conjunction with a mixer makes it most suited to a dedicated set-up. It is very smart and professionally built inside and out and offers as good a performance as you will get from any rack-mounting spring reverb.

Just as you will get no nasty surprises from their springs you should get no nasty surprises from their prices either. The RV-2 retails for £275 inc VAT and depending on exchange rates at the time of import, the RV-3 should cost around £215 to £220 inc VAT.

For further details on the RV-2 and RV-3 contact: MTR, (Contact Details).