BBE 362 NR

BBE's new Sonic Maximizer combines enhancement with single‑ended noise reduction. Paul White finds out whether the marriage of the two systems is a happy one.

As most regular SOS readers will know, BBE's patented process is a means of enhancing an audio signal to improve the sense of detail and transparency, but unlike the Aphex system, which is based around harmonic synthesis, BBE's is more concerned with redistributing the harmonics that are already present. Apparently, the process was first devised to counteract the phase smearing that occurs in typical passive loudspeaker systems. It does this by breaking the audio spectrum down into three bands, then applying small delays to the lower two bands. The signal is delayed by around 2.5mS between 20Hz and 150Hz, whereas mid‑range signals between 150Hz and 1200Hz are delayed by just half a millisecond. Above 1200Hz, the signals are not delayed, but are subjected to some form of dynamic amplitude control which has the effect of emphasising high‑frequency, transient detail. As heavy processing can cause the top end to overpower the bottom end, a low‑frequency equaliser permits the user to add boost at 50Hz to compensate.

It's well proven that all types of enhancer can make a significant contribution to musical clarity, but because all increase the amount of high frequency energy in the signal, albeit slightly, there's always the risk of emphasising any noise already present in the input signal. Many people, including myself, have at some time or other used a combination of enhancer and single‑ended noise reduction to clean up master recordings or sweeten old mixes, and now BBE have taken the step of combining both processes in a single 1U box.

The BBE 362NR is a dedicated stereo unit with ganged controls, and is optimised for ‑10dBV applications. Jack and phono In/Out connectors are provided, both offering unbalanced operation only. The DNR (dynamic noise reduction) circuit comes right at the end of the signal chain before the output sockets, and is actually very simple, being based around a frequency‑conscious envelope follower, which in turn controls an LED/LDR combination. The LDR (light dependent resistor) forms part of a straightforward RC (resistor/capacitor) filter, and as the resistance changes, so does the roll‑off frequency of the filter. In practice, as the signal level falls to the point where noise might become a problem, the filter starts to close, removing progressively more of the high frequencies which, in most cases, should be mainly noise. The BBE part of the circuit is handled by BBE's proprietary chip.

Controls

What's going on beneath the casing might be pretty clever stuff, but the user interface is really very uncomplicated. Once the BBE process is switched in via the Bypass button, a Process control sets the intensity of the enhancement by varying the amount of top frequency band information, and a Lo Contour knob adds the 50Hz bass boost if desired. Clip LEDs are fitted to both input channels which come on at 3dB below clipping, and a status LED shows when the BBE effect is active.

The noise reduction section is equally lucid, and aside from its own bypass switch, labelled Function (again with a status LED), there's only Threshold and Release to worry about. Threshold determines the level at which the SNR system starts to reduce the top end, and must be set carefully by ear Release governs the time it takes for the dynamic filter to come into action once the signal level has fallen below the threshold. If the threshold is too high, audible high‑frequency loss may become evident, whereas if it is too low, the noise reduction won't be as effective as it could be. The Release control should normally be set as fast as possible without producing any audible noise pumping effects.

In Use

As expected, the enhancement side of the 362NR works pretty much as on the BBE units I've used on previous occasions, and although I still hold to my opinion that the results you can achieve using this process aren't quite as crisp and dramatic as when using a Vitalizer, or Aphex, the BBE process is arguably more subtle, and consequently more difficult to over‑use. With well‑recorded material, the BBE 362NR enables you to add a worthwhile degree of warmth at the low end, as well as clarity and space at the top end, and because the process is based on the existing signal, it doesn't tend to become over‑harsh, even when the Process control is wound right up.

The SNR (single‑ended noise reduction) side is equally smooth, but because there is no metering to show you what activity is taking place in the filter department, you have to keep switching the bypass switch in and out as you set the threshold, to make sure that you aren't compromising the top end. Once you've set the threshold for minimal tonal change at normal signal levels, you should find that the noise during low‑level passages has been noticeably reduced. The key here is that noise can only be reduced and never totally eliminated, so there's no point using the BBE 362NR to try and disguise a poor recording. On the other hand, if the noise contamination is relatively modest, the 362NR can certainly make a noticeable improvement without altering the wanted part of the signal. It's worth noting that the process isn't only suitable for using on complete mixes — slightly noisy synths or even guitars can be cleaned up at the recording stage, then when you come to mix, you can use the 362NR again if you need to.

Conclusion

To BBE or not to BBE; that is the question. If you're into adding subtle refinements to your music, then the answer is unquestionably yes, the 362NR will do a good job, it won't ruin your tonal balance, and it includes a useful noise reduction system to boot. As with all the other enhancement methods, it does manage to open up the mix nicely, but if you're into dramatically changing the tonality of your mixes so that you can carve the ears off bats at 100 paces, then maybe one of the other systems would suit you better. One of the main tenets of the BBE process is that nothing is synthesized or added, but sometimes, when you're working with an intrinsically dull sound, the capability to add new harmonics is a lifesaver.

In its favour, the BBE is very easy to set up, especially if you haven't had much prior experience with enhancers, and the SNR capability for noise taming is extremely useful providing you don't expect too much of it. I feel that too many records are mixed with far too much top end, the result being that they are fatiguing to listen to. As implied earlier, the BBE system is the least likely to cause harshness problems if used over‑zealously.

The BBE process has been around for a long time — it works well, and only first‑hand listening tests will tell you whether or not you prefer it to the competing systems. I can find merits in all the available approaches, but nobody offers a single unit that combines all the attributes of the different enhancement systems, so in the end, the decision is purely a subjective one.