SPL Transient Designer 2

Paul White checks out the new two‑channel version of SPL's innovative dynamics processor.

SPL's Transient Designer is one of the less well‑understood processors doing the rounds at the moment. The original version featured four independent channels and was consequently rather costly, so when SPL announced a two‑channel version it seemed a good opportunity to revisit the concepts behind this unique device. The Transient Designer relies on the principles of both compression and expansion, though it is neither a compressor nor an expander in the accepted sense. The all‑analogue circuitry does use VCA gain control but, rather than control gain as a compressor does, the Transient Designer directly (and dramatically) affects the envelope of transient sounds being processed, regardless of their level. The process allows you to inject a bland drum recording with a lot more edge and attack or, conversely, to soften the attack of overly percussive sounds and vary the apparent amount of damping.

Attacking The Hardware

Each channel simply has balanced input and output jacks round the back, and an Attack control, a Sustain control, a Bypass button and an activity LED at the front. There's no need for a Ratio control or gain‑reduction meters, because the whole process is pretty much independent of signal level. A further button in the centre of the front panel allows the two channels to be linked for use as a stereo pair. Both the Attack and Sustain controls provide positive and negative control with a zero (no processing) point midway. Relays bypass the channels completely when the process is switched off or if the power goes down.

Setting up is accomplished entirely by ear, and because the process is level‑independent, the effect doesn't vary as long the signal level doesn't stray below ‑40dB. The LED lights when the signal is above this level, to show that the process is active. The rotary controls allow direct modification of the attack and sustain characteristics of natural sounds by using two envelope followers with different response times. When their control voltages are subtracted from each other, the resulting signal can be used either to increase or decrease the level of only the attack or sustain sections of the audio signal. Attack transients can be cut or boosted by up to 15dB while the sustain portion of sounds can be increased or decreased by up to 24dB. As we've come to expect from SPL, the audio signal path is clean and quiet — a THAT 2181 is used as the VCA gain control.

Does It Work?

Last time around I described the Transient Designer as a 'results‑orientated' device, and I think that description is fair — you use it when you need to change the subjective character of a percussive or transient sound. I patched the Transient Designer into a console insert point and proceeded to bombard it with test material to see what it could do. You get a result with most material that has any kind of percussive element but, for the most control, it's best to process individual tracks or submixes. As the Attack control is turned up from its centre position, percussive sounds assume a sharper, better‑defined attack, whereas if you move the control anti‑clockwise from centre, the original attack is softened. Bass lines respond quite dramatically, though drum parts give the most clear cut results.

The Release control has more range than the Attack control. Move it anti‑clockwise and drum sounds dry up as though more damping had been applied when they were recorded. It also diminishes the effect of any room reverb. Turn the control clockwise and the 'ring' of the drum heads is emphasised along with any room ambience. However, unlike a compressor, the Transient Designer's ability to treat every sound the same, regardless of level, makes it very intuitive to use.

I was impressed at how naturally an underdamped drum sound could be made to seem tighter or an overdamped drum kit could be given more sustain and life. I must stress that the range of adjustment is enormous despite the simplicity of the controls. In fact, there is so much range to the process that an integral limiter would have been a useful addition to this box in order to tame any over‑enthusiastically enhanced peaks! This makes this box really useful for converting acoustic drum samples into monster dance sounds — anyone tackling dance music without one of these babies is going around only partially equipped for the job.

Conclusions

The Transient Designer really is a unique product which, while not a tool for processing sound in the traditional sense, is nonetheless very capable of shaping sounds in musical and intuitive ways. What's more, it's so simple to use that even the least experienced user can take control over their rhythm sounds, either fine‑tuning them or wrenching them into a new shape entirely.