Dual Compressor/Gate: Adding a dbx 266xs Compressor/Gate to your live
sound rig or studio gives you more dynamic control to help create a more
polished, professional sound. Having compression in your audio chain gives you
the ability to smooth out uneven levels, add sustain to guitars and fatten up
your drums. It also makes it easy to bring vocals to the front of your mix -
adding greater clarity and making them stand out from the surrounding
instruments. The dbx 266xs employs patented Overeasy compression technology that
provides smooth and musical performance while the AutoDynamic attack and release
controls, found only on dbx compressors, puts great sound within easy reach. The
266xs can operate in stereo or dual-mono modes, has true RMS power summing and
features quality XLR and 1/4" TRS inputs and outputs. It also offers visual
feedback with gain reduction metering and easy-to-read backlit switches.
Compressor: The 266xs compressor is packed with just the right
features to effectively reduce and control the dynamic range of your audio, add
punch to flabby, loose sounds, or add sustain to instruments. The 266xs
employs Program-dependent Attack and Release controls with dbx's AutoDynamicT
circuitry, so that the full range of controls produce voicings that extend from
slow leveling to aggressive peak limiting.
- OverEasy Mode: The 266xs OverEasy compression permits extremely
smooth, natural sounding compression, without artifacts, due to the gradual
change of compression around the threshold. With OverEasy compression, input
signals begin to gradually activate the 266xs internal gain change circuitry
as they approach the THRESHOLD reference level. They do not get fully
processed by the Ratio, Attack, and Release controls until they have passed
somewhat above the Threshold reference level. As the signal level passes the
Threshold level, processing increases until it is fully processed to the
extent determined by the control settings.
- Hard-Knee Mode: In hard-knee mode, the 266xs can provide abrupt
compression effects as well as hard-limiting applications. Note that when in hard knee mode the amber LED will not light
as the input signal passes across the threshold. The signal is either being
compressed (over threshold) or it is not being compressed (under threshold).
Note: Common compressor applications include fattening a kick drum or
snare drum, adding sustain to guitar or synthesizer string sounds, smoothing out
a vocal performance, raising a signal out of a mix, preventing sound system
overload, or digital to analog transfers.
Gate: The 266xs gate is ready to tackle all your gating needs, whether
you need to remove unwanted noise or other background sounds, tighten drum
sounds, or change the characteristic envelope of an instrument. The 266xs gate
provides more flexibility than traditional switch gates because it actually
functions as a combination gate/expander. Where switch gates are generally only
suitable for a limited number of uses (e.g., gating percussion), the gate on the
266xs acts as a gentle downward expander at low Ratio settings (suitable for
vocals, guitar, mixed program, etc.), and can effectively work as a switch gate
when used at high Ratio settings.
Note: Common gate applications include gating dry percussive sounds
(snare or kick drum), gating sounds that have longer decay (cymbal or piano),
gating hum or buzz from live instruments or recorded tracks, and downward
expansion to reduce noise under smooth sounds (vocals or woodwinds).
Inputs/Outputs: The 266xs is fitted with a variety of XLR and 1/4"
inputs/outputs that accept both balanced and unbalanced audio signals.
- 2-Channel Inputs: Channel 1 and Channel 2 inputs each feature a
female XLR connector and female 1/4" TRS phone connector. These input jack
will accept both balanced and unbalanced signals. Input impedance is >40kΩ.
- 2-Channel Outputs: Channel 1 and Channel 2 outputs feature a
female 1/4" TRS phone connector and a male XLR connector. The output jacks
support both balanced and unbalanced audio signals. Maximum output signal
level is >+20dBu. In the +4dBu setting, the balanced output impedance is
100Ω, and the unbalanced output impedance is 50Ω. In the -10dBV setting, the
balanced output impedance is 1kΩ and the unbalanced output impedance is
- Sidechain Insert Jack: This jack accepts 1/4" TRS phone plugs and
provides a connection to the 266xs detector path. The Ring acts as a Send,
carrying a buffered version of the signal present at the 266xs Input jack,
at an impedance of 2kΩ. The Tip acts as a Return for equipment to feed the
266xs detector circuitry, such as an equalizer for de-essing or
frequency-sensitive gating/compression. You can also drive the 266xs
Sidechain input with the output of most equipment, by using a 1/4" mono
phone plug. Input Impedance is greater than 10kΩ.
Note: When a cable is plugged into the Sidechain Insert jack, it automatically breaks the
the Input jack to the 266xs detection circuitry.
Attack & Release Control: The 266xs provides Attack & Release control.
- Attack: The Attack control sets the amount of time it takes the
266xs to begin compressing a signal once the detector has sensed a signal
above threshold. The Attack range is from Fast (for a tighter and more
noticeable compression effect with very little overshoot) to Slow (for more delayed, gradual compression). A very fast Attack setting will cause the
266xs to act like a peak limiter even though RMS detection circuitry is
used. Slower Attack settings cause the 266xs to act like an RMS or averaging
- Release: The Release control sets how fast the compression
circuit returns the input to its original level. The Release rate is from
Fast (where compression follows the envelope of the program material very
tightly) to Slow (for very smooth compression).
Note: The Auto switch overrides both the Attack and Release controls and enables
preset program dependent attack and release times. These times are derived from
the input signal and continuously change to match its dynamics.
Compressor & Expander/Gate Ratio Control: The 266xs features both
Compressor Ratio and Expander/Gate Ratio controls.
- Compressor Ratio Control: Adjust this control to set the amount
of compression applied to the input signal. Clockwise rotation of this
control increases the compression ratio from 1:1 (no compression) up to ∞:1
(where the compressor can be considered to be a peak limiter, especially
with faster Attack settings).
- Expander/Gate Ratio Control: This control sets the amount of
attenuation applied to the input signal once it is below the threshold, from
gentle downward expansion (appropriate for mixed program, vocals, etc.), to
a hard gating effect (which can be useful for percussion). Fairly low
Ratio (and higher Expander/Gate Threshold) settings work best for downward expansion, whereas
higher Ratio settings (clockwise towards Max) work best for gating. If a
setting produces undesirable pumping, readjust the Expander/Gate Ratio or
Other Controls: The 266xs offers a variety of control dials and
switches to fine tune the Dual-channel compressor/gate.
- Operating Level Switch: This switch selects between a -10dBV and
+4dBu nominal operating level. When the switch is in the in position, a
-10dBV operating level is selected. When it is in the out position, a +4dBu
operating level is selected.
- Stereo Couple Switch: This switch sets the 266xs for Stereo or
Dual Mono operation. Press the Stereo Couple switch in for stereo operation where Channel 1 becomes the master controller for
both channels. All of Channel 2's controls, switches, and LEDs will be
disabled (except for the Channel 2 Gain Reduction meter), since Channel 2 is
the slave. With the Stereo Couple switch out, the unit functions as two
separate mono compressor/ gates, each with its own independent controls.
- Bypass Switch: Press this switch in to bypass the front panel
controls, effectively canceling the function and processing effect of the
266xs compression, gating and gain settings. The input signal is still
present at the 266xs Output, but is now unaltered by the 266xs controls.
Bypass is especially useful for making comparisons between processed and unprocessed signals.
Note that with stereo operation (Stereo Couple switch pressed in), the
Channel 1 Bypass switch controls both channels.
- Output Gain Control: This control sets the overall gain of the
266xs, from -20dB to +20dB. The Output Gain control is especially useful to
compensate for the RMS level decrease which results from the 266xs dynamic
processing effects. After you adjust the 266xs controls for the desired
amount of compression, set the Output Gain to add the same amount of gain
that is shown on the Gain Reduction meters. For example, if the average
amount of gain reduction shown on the meters is 10dB, then setting the
Output Gain control to +10dB will compensate for the 10dB average level
reduction at the output.
Gain Reduction Meter: This meter displays the amount of signal
attenuated from the input signal by the 266xs Compressor or Expander/Gate. When
the Compressor and Expander/Gate are both active, the meter displays the maximum
amount of gain reduction for whichever function is greater - Compressor or
Input (Balanced or Unbalanced):
- Impedance: > 40kΩ
- Max Level: +22dBu
Output (Impedance Balanced):
- +4dBu: 100Ω Balanced / 50Ω Unbalanced
- -10dBu: 1kΩ Balanced / 500Ω Unbalanced
- Max Level: > +21dBu, > +18dBm (into 600Ω)
- Input Impedance: >10kΩ
- Output Impedance: 2kΩ
- Max Input Level: +22dBu
- Max Output Level: >+20dBu
- Flat: 20Hz-20kHz, +0, -0.5dB
- Bandwidth: 0.35Hz-90kHz, +0, -3dB
- Distortion + Noise: <0.2%; any amount of compression at 1kHz
- Intermodulation Distortion: <0.2% SMPTE
- Noise: <-93dB, unweighted (22kHz measurement bandwidth)
- Dynamic Range: >114dB, unweighted
- Interchannel Crosstalk: <-95dB, 20Hz to 20kHz
- Common Mode Rejection: >40dB, typically >55dB @ 1kHz
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