Ever wondered how commercial studios manage to bring that certain magic to their recordings - a magic which often evades those working with hi-tech set-ups at home? Ian Masterson has the answer...

Bass - how low can you go? Not far enough, most of the time. Massive PA rigs with massive bass bins tend to cost massive amounts, and for the gigging musician or club-hopper the limitations of small venues with small sound systems can completely destroy any definition at the low end of the frequency spectrum. The problem is one of getting your straining loudspeakers to just push that little bit more in terms of volume, while retaining the integrity of the sound. And once you've fleshed out the bass, you'll need to tweak the mid range to match. And perhaps add a little 'sparkle' over the top...

PA engineers have been aware of SPL's Vitalizer for some time now; when it comes to putting the punch back in a kick drum, or sending the vocals spinning across the crowd, there is little to match it. And in the studio, producers are all too aware of the difference the Vitalizer can make when it comes to coaxing just that little bit more bass onto a 12", or making a radio mix jump out of their monitors. But now the guys at SPL have introduced the next generation - the Stereo Vitalizer. Same tricks as before, with the addition of a new stereo width processor, designed to radically enhance the separation of your signal.

For those unfamiliar with the Vitalizer concept, it's perhaps beneficial to start with a brief recap of the way things actually work inside this machine. Connections to and from the unit are provided on both balanced XLRs and unbalanced 1/4" jacks; the Vitalizer has an internal mains power supply, and comes complete with ground lift switch to eliminate possible earth loop hum. Starting from the left, the front panel features bass enhancement, mid-range frequency tune, harmonics, processing level and stereo width rotaries, together with switches to defeat the entire unit, or defeat only the stereo separation. Input level is monitored on two rather 'vague' red clipping LEDs; a bargraph meter might have been a more worthy inclusion on a unit of this price.

As on the original Vitalizer, bass enhancement is facilitated by means of a single rotary, which when turned to the left boosts the bass in a heavy, 'soft' manner ('Sub bass'), and when turned to the right increases it in a 'tight', more defined way. This control is completely different to the low-range adjustment found on a parametric EQ. Here, the signal is harmonically reprocessed to increase the perceived loudness and intensity of the sound - the actual volume of bass stays pretty much the same. The Vitalizer basically synthesises harmonics around the frequencies appearing at the input, making the low frequencies sound much more solid and dominant. Clubbers will delight in the sub-surface rumblings produced by turning this control to the left; producers looking to enhance sequenced Juno basslines will definitely tweak to the right.

The mid- and high-range controls are slightly different in their operation; you select the mid-range 'area' of frequencies you wish to be enhanced (from 22kHz to 1 kHz), the level of top end 'sweeting' required via the harmonics knob, and then the amount of enhancement. This is actually governed by the process depth rotary (pretty much like the wet/dry mix control on any reverb) which also affects the level of bass enhancement. For example, if your mid-range cabinets are drowning out the top horns and muffling the bass, the Vitalizer will not only boost the low end action (without stressing your amplification), it will zoom in on the upper range and add previously unnoticed detail to the mix.

But the real gem in the new version of this black magic box is the stereo width expansion circuit. Once again, a single rotary controls all the functions - but this is all you need. An internal network of phase-shifters and frequency-conscious filters simply takes the stereo elements of your original signal and literally 'opens them up'. The effect is not unlike a simplified version of Roland's RSS System - it introduces a sense of 'space' around all the elements of a mix, while retaining the balance of the various instruments.

As usual, the audible effects produced by a unit such as the Vitalizer tend to be almost impossible to describe in print - or indeed in words at all. This is one of those units which just has to be heard to be understood and appreciated. I would strongly recommend taking a DAT of one of your favourite mixes to a friendly audio retailer and witnessing the impact SPL's latest technology can have on your music - suddenly the sounds you dream of achieving in expensive commercial studios are available in your own system. And if you want to shake your audience's lungs at your next gig, hire one out to experiment with. It's workings may be a mystery, but the results are all too obvious.

THE LAST WORD