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Dbx 266XL

Compressor/Gate By Paul White
Published September 1998

DBX 266XL

Does the new 266 compressor from dbx really excel?

With the signal processor market so crowded it must be very difficult for a manufacturer to come up with a new product that will fire the imagination of the end user — which is probably why so many resort instead to building 'me too' products and trading blows on prices. Nevertheless, dbx have a long‑held reputation for building VCA compressors that have a specific sound (as opposed to being transparent), so they've been careful not to change things too much when designing the new 266XL.

Physically

The dbx 266XL is a fairly standard looking 1U rackmounting 2‑channel compressor/gate, though the gate is actually a variable‑ratio expander, making it rather more flexible. Much of the compression stage is based on that of the popular dbx 160, and to provide the greatest flexibility there's an OverEasy/Hard‑knee switch and the option of manual or auto Attack and Release settings. OverEasy is, of course, dbx's own interpretation of soft‑knee compression.

The unit is mains powered, though there's no mains switch, and the audio ins and outs are on both balanced XLRs and balanced jacks for convenience. Unbalanced jack connections may also be made using regular single‑pole jack leads. Side‑chain insert points for the compressors are also present, in this case on TRS jacks. RF filtering is provided on the main input and the insert send and return points.

On vocals it's good for creating an overtly compressed sound, and it also works very well on acoustic guitar.

Two controls, Threshold and Ratio, are used for the Expander section. At high ratios (4:1 is the maximum) the expander behaves much like a conventional gate, whereas at lower ratios the gain control is much more progressive, making it more useful for dealing with non‑percussive sounds. A red LED comes on when the signal is below threshold and a green LED lights when the signal exceeds it. Any gain reduction due to the expander shows up on the main compressor gain‑reduction meter which, quite frankly, I found confusing and rather unsatisfactory. In practice, you have to back off the expander threshold so that the expander isn't working before you can set up the compressor properly.

The compressor has rather more controls, featuring knobs for Threshold, Ratio, Attack, Release and Output Gain. Ratio is continuously adjustable from 1:1 (no compression) to hard limiting. A 3‑LED system shows when the input is below threshold, above threshold or (when OverEasy is selected) in the OverEasy area. Gain reduction is indicated by a 9‑LED meter. A button selects hard or OverEasy mode, and a second button overrides the Attack and Release controls to provide program‑dependent operation.

Auto mode is designed to duplicate the characteristics of a 'classic' dbx compressor, according to the manual, though elsewhere in the manual it's stated that setting both attack and release to their 12 o'clock position will also produce the traditional dbx sound. The term AutoDynamic (followed by the inevitable trademark symbol) is mentioned in conjunction with the attack and release characteristics of the unit, though no description of its operation is included.

A single Bypass button works on both the expander and compressor sections, and both channels may be linked for stereo operation using the Stereo Couple button.

Dbx 266XL compressor/gate

In Use

I know a lot of engineers who love the dbx sound for treating bass guitars, and the 266XL doesn't disappoint in that area. It is also effective on individual drum sounds, though when you're processing a whole kit there's a tendency for the compressor to pump noticeably. Of course, pumping is a characteristic of many vintage rock and pop records, so it may be that this effect is exactly what you want. Oddly, even setting OverEasy and Auto together still results in a fairly obvious compression characteristic, and when using more than around 8dB of compression on vocals I found that the Auto setting sounded distinctly fluttery. I achieved better results by setting the time constants manually. Similarly, I found it very difficult to get any worthwhile results on complete mixes, as the compression was always too unsubtle for my taste — I like to use fairly transparent compression on mixes.

I get the impression that most dbx compressor fans treat these compressors more as effects than as a means of controlling dynamic range.

Summary

I get the impression that most dbx compressor fans treat these compressors more as effects than as a means of controlling dynamic range, and if you view the 266XL in this light it works very well indeed, especially on drums and bass. On vocals it's good for creating an overtly compressed sound, and it also works very well on acoustic guitar. However, if dbx have added the Auto mode and Hard/Soft switching in an attempt to make the 266XL more of an all‑rounder, I don't really think they've succeeded.

Technically and ergonomically this unit is excellent, with the exception of the shared gain reduction meter and the lack of a separate expander bypass switch. However, for me the 266XL is still best suited to getting those classic dbx 'compressed and loving it' sounds, and is less attractive as a general‑purpose compressor. With that in mind, I'd recommend it to anyone who already has a reasonably transparent compressor, but I wouldn't want to have it as my only means of compression.

Pros

  • Delivers the classic dbx compressed sound.
  • Comes with a very smooth expander.
  • Good technical spec.

Cons

  • Expander and compressor share the same gain reduction meter.
  • Auto mode still produces audible pumping on some material.
  • Less effective at routine gain reduction jobs where you don't want to hear the compressor working.

Summary

A cost‑effective way to acquire classic dbx compression, with a very nice expander thrown in.

Published September 1998