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DBX Project 1 Model 286

Microphone Processor By David Mellor
Published January 1997

This new voice channel aims to provide all you need to get a good sound from a mic, at a reasonable price. David Mellor tries it out.

Getting a great vocal sound is a skill that eludes many home recordists and even, judging by what I hear on CD, pro engineers occasionally. The first step, in an ideal world, would be to use a really good vocal mic, but since we're talking about a price tag of more than a thousand pounds, perhaps substantially more, that isn't an option for most of us. There are mics in lower price ranges that will turn in a really good vocal performance, given a bit of careful processing, but to hook up all the equipment you might need is time‑consuming and inconvenient.

Several manufacturers have identified this situation, and have produced so‑called 'voice channels' which incorporate a mic preamp and various processors that will enable you to tweak the sound to near perfection — given a good singer and an appropriate mic placement, of course. Products of this kind (though more expensive than the dbx unit) include the Focusrite Green Voicebox, the TL Audio 2051 Valve Voice Processor, and the LA Audio Classic Channel (all reviewed November 1996), and the Symetrix 528E Voice Processor. The dbx Model 286's price point will certainly make it very attractive if it delivers the goods. I've had a Symetrix 528E in my rack for about six months now, and it's great just to be able to plug the mic in and start work, rather than starting the session by knitting patch cords.

What It's Got

The kind of processes you would commonly need for vocal recording are compression, equalisation, de‑essing and gating, and the dbx Model 286, part of the Project 1 range of processors, provides all of these in an appropriate way, in one unit. There is a school of thought that you should record flat with no processing and save any tinkering for the mix, but the fact is that you nearly always need to correct minor deficiencies in the sound before thinking about improving it. As long as you don't process too severely, you'll be making your life easier later on and not restricting your options in any way.

The Model 286 comes in a shallow, rackmounting case with a line‑lump power supply (which, to my mind, doesn't quite convey the appearance of quality that a £350 unit should). It has a single‑channel mic preamp (or line input), compressor, de‑esser, equaliser and expander/gate, connected in that order.

Mic Preamp

It is conceivable that you might want to use the mic preamp of the Model 286 without any further processing, which you are able to do using the Process Bypass switch. The gain control runs from +10dB to +50dB, which should take care of most situations, although there is no pad available. There is an 80Hz, 18dB/octave high‑pass filter for cutting out unwanted low frequencies and reducing, to some extent, the proximity effect of directional microphones. 18dB/octave is a steeper slope than is commonly found, but I'm in favour of steep slope filters generally — or at least having the option, since subjectively they 'do more' to the sound. My only quibble about the mic preamp is that the phantom power is only 15 volts, instead of the standard 48V. By no means all capacitor mics are specified to work over a range of voltages other than 48V and you couldn't be certain that your mic would work well with this unit without first trying it out. It's possible that some mics wouldn't give a usable result at all, while others might have a reduced dynamic range. The unit works well with my AKG C414EB, however, which shows that it need not be a problem, but you'd have to check the spec of your mic to make sure before parting with your cash. With dynamic mics, of course, you don't need the phantom power and you can switch it out.


On a voice processor, you don't necessarily need the full range of compression controls that you'd find on a dedicated compressor. Here we find just two — Drive and Density. The compression is of the 'over‑easy' type, where the ratio increases as the signal level gets higher. The Drive control therefore controls the degree of compression. Conventional compressors have a release control, which governs the time taken for the signal level to return to normal once it has dropped back below the compression threshold. On the Model 286, the actual release time is program dependent, and the Density control speeds it up or slows it down. With just these two controls, you can, in fact, get a very smooth compression that is exactly right for vocals, and with care your recording need never sound over‑compressed. An 8‑stage LED bargraph shows the amount of gain reduction occurring at any moment.


This is the section that I have the most reservations about using during the actual recording of the vocal. Many singers produce over‑prominent 's' sounds which need taming, but if the de‑essing is overdone the singer can end up sounding as though they have a cold! And there's no way, at least with current technology, that you can 'un‑de‑ess'. Still, if you were working with the same vocalist frequently, it wouldn't be hard to work out the ideal setting, and that should be safe to use during recording. The de‑esser section of the 286 has just a threshold control, which sets the sensitivity of the de‑esser as a percentage of the average signal level, which is rather better than de‑essers that set a fixed threshold. I would have liked some control over the frequency range, however. An LED indicates when the de‑esser is active.


Some enhancers work by adding a controlled amount of distortion to the signal. This one doesn't and is more akin to an equaliser. The LF Detail control applies a boost at 80Hz and a cut at 250Hz simultaneously. As you are probably aware, boosting low frequencies can often make the sound quite 'muddy'. This is usually due to boosting frequencies other than those that would subjectively add bottom end to the signal. You might wonder why the 80Hz boost frequency is the same as the frequency you may have chosen to cut in the mic preamp stage. The preamp comes before the compressor, of course, and you are correcting a problem that could make the compressor do strange things to the signal. Here you have the opportunity of being just a little more creative. The HF Detail control, once again, is more than a simple EQ. Here the signal is apparently analysed intelligently, and automatically determines the amount of equalisation necessary at each moment. It's claimed to produce audio that is detailed, defined and never shrill or over‑sibilant. That's a lot for one little knob to attempt, but within the limits of what you can do with 270 degrees of rotation, it's certainly effective and offers something just a little different to the norm. And you can still EQ on your console, or with an external EQ unit via the 286's insert point, if you need to.


One of my personal rules of recording is never to gate the vocal as it is going down to tape or disk. Unless you're clever about it, you'll also gate the feed to the vocalist's headphones, and it can be disconcerting to be 'on' one moment and 'off' the next. There's also the significant risk that you will gate out some quiet sounds that you really need to capture. The Model 286's expander/gate is a different matter, since you can set a ratio of expansion from hardly any at all up to 10:1, and the threshold is variable too. This means that you can reduce the low‑level clutter in the signal, such as breaths, but the vocal proper won't be affected. Don't forget that compression raises the noise floor of the signal, and you will almost certainly need to deal with this in some way. An LED indicates when the signal is below the expander's threshold.

At the end of the chain is an output level control, which will prove necessary to make up the gain that is inevitably lost in the compression process. There's not much I can say about that, except that I'm very happy that it's there (especially since output level controls are increasingly absent in signal processing equipment).

A Good Buy?

As I indicated at the beginning of this review, the first priority of any studio (except if it's only intended for instrumental recording) should be to buy a really good vocal mic. However, that's going to cost you really serious money, and there's a case to be made for buying a cheaper mic (but still of professional quality, such as the AKG C3000 or Audio Technica AT4033a) and spending the money you have left over on a dbx Model 286. The result would be a wider sound palette to work with than someone who'd spent all their cash on one mic. Of course, the Model 286 has a line input too, so you're not restricted to using it exclusively for recording vocals — I use my own Symetrix 528E frequently on line‑level sources, and for playing about with individual tracks at the mixing stage. You can rest assured that once the vocal is down on tape, the Model 286 won't be resting expensively idle in your rack, but will continue to earn its keep all the way through the session.


  • Easily beats the average mixing console channel.
  • Good combination of features.
  • Good value for money with respect to much of the competition.


  • 15V phantom power, rather than the standard 48V.
  • Line lump power supply with two‑pin plug!
  • Looks and feels a little bit cheap at the price.


A versatile and effective mic (and line) processor. With an internal power supply, full 48V phantom power and a more solid appearance it could compete with the best.