Overview: The dbx 231s dual 31-band graphic equalizer is a versatile,
professional-quality EQ with simple, straight-forward controls. It features two
independent channels and 31 frequency bands, broken down in 1/3-octaves. Each
non-conductive slider has approximately 1" of movement with a detent at the 0
(flat) position. The 231s fits neatly into a standard equipment rack (2U space
required), and includes 4 rack mount screws and washers.
Input Gain: The 231s is equipped with a rotary input gain control to set the
signal level to the equalizer. The input gain control has a range of -12dB to
+12dB. You can monitor the input to the EQ through the 4-LED Output Level Bar
Graph, which has green (2), yellow (1), and red (1) indicators. There is also a red LED
to indicate if the input signal is clipping. The 231s has independent input gain
controls for each channel.
Frequency Bands: The 231s includes the following frequency bands: 20Hz, 25Hz,
31.5Hz, 40Hz, 50Hz, 63Hz, 80Hz, 100Hz, 125Hz, 160Hz, 200Hz, 250Hz, 315Hz, 400Hz,
500Hz, 630Hz, 800Hz, 1kHz, 1.25Hz, 1.6Hz, 2kHz, 2.5kHz, 3.15kHz, 4kHz, 5kHz,
6.3kHz, 8kHz, 10kHz, 12.5Hz, 16kHz, and 20kHz.
Switchable Boost/Cut Range: The dbx 231s has a maximum boost/cut range of +/-
12dB. If desired, you can switch to a range of +/- 6dB. This gives you finer
control within the range. The boost/cut range switch is located on the front
panel. When the button is pressed in, the button lights up to indicate the range
is +/- 12dB. When the button is in the out position, the range is +/- 6dB, and
the button is unlit. There are Boost/Cut Range switches for each channel.
Low Cut: To instantly cut out low frequencies, you can engage the built-in
50Hz 12dB/octave high pass filter. The Low Cut switch is located on the front
panel, and remains lit when pressed in and activated. There are Low Cut switches
for each channel.
EQ Bypass: Each channel has an EQ Bypass switch, which bypasses the graphic
equalizer section in the signal path, when activated. An EQ Bypass switch is
provided for each channel, and remains lit when engaged.
Inputs: The dbx 231s is equipped with a 1/4" TRS (tip/ring/sleeve) phone jack
and a female locking XLR (pin 2 hot) input connector for each channel. Each
input can accept balanced or unbalanced input sources. The maximum acceptable
input level is typically +22dBu (ref: 0.775Vrms).
Outputs: Each channel has a 1/4" TRS phone jack and a male XLR output
connector. The outputs can be used with either balanced or unbalanced loads. The
maximum output level is greater than +21 dBu balanced/unbalanced into 2 kΩ
or greater, >+18 dBm balanced/unbalanced (into 600Ω).
AC Power: The 231s has a 3-pin IEC power cord receptacle, and accepts 100-240
- Frequency Response: <10 Hz to >50 kHz, +0.5/-3 dB
- Bandwidth: 20 Hz to 20 kHz, +0.5/-1 dB
- Dynamic Range: Typically >112 dB
- Signal-to-Noise: Typically >95 dB
- THD+Noise: <0.003%
- Interchannel Crosstalk: <-90 dB, 20 Hz to 20 kHz
- Input Impedance: Balanced 40 kΩ, Unbalanced 20 kΩ
- Output Impedance: Balanced 100 Ω, Unbalanced 50 Ω