Preamp Processor
US $4,819.01




- Stereo Inputs -
  - Analogue - RCA unbalanced, XLR balanced
  - Digital - TOSLINK, S/PDIF BNC, S/SPIF RCA, AES3 XLR, USB (now included)

- Stereo Outputs -
  - Analogue - Low, Mid (or full-range), High: RCA unbalanced and XLR balanced
  - Digital - Low, Mid (or full-range), High: S/PDIF BNC
  - Digital Thru - S/PDIF BNC

- Measurement Mic Input - XLR balanced with 48v phantom power

- Mains Input Voltage - Switchable 115v-230vAC, 50-60Hz

- Power Consumption - 50VA

- Dimensions -
  - Height - 2U / 97mm
  - Depth - 325mm
  - Width - 430mm

- DSPs - Dual Analogue Devices SHARC 32-bit floating point

- Analogue Input Maximum Levels -
  - Balanced -
+17 dBu differential
  - Input Impedance (balanced and unbalanced) - 50 kohms

- Analogue Output (jumper set) Maximum Levels -
  - Balanced Maximum Level -
+21 dBu differential
  - Unbalanced Maximum Level - +15 dBu differential

- Total Harmonic Distortion - <0.0008% (analogue-analogue)

- PC Connections - USB or RS232

- Crossover Slope (software selectable) - up to 300dB/octave

- Latency - from 2.5ms, typically 15ms with speaker correction filters (video sync OK)

Master the art of timing
DEQX processors correct the distortion that all speakers make—electro-mechanical devices that they are—and offer room compensation as an added extra. While righting frequency-response errors as other units do, they also uniquely fix critical timing errors by adjusting thousands of frequency groups so that they arrive on time.

Other ‘room correction devices’ simply adjust amplitude response (uneven output at different frequencies) to offset room modes. But they can’t address the fine details of phase coherence; the group-delay timing issues that manifest in all real-world speakers.

The results are startling; two-channel and surround systems open up in a dramatic way when timing, phase and amplitude accuracy are restored to the speakers, with judicious room compensation added.


The HDP-4 can be installed between your preamp and amplifier or more directly used as a preamp processor.

It accepts up to 24/176.4 and 24/192 digital inputs and now supports TOSLINK in, plus an optional USB input module. Stereo digital and analog inputs include SPDIF, AES/EBU, unbalanced analog and balanced analog.

The HDP-4 comes standard with many output options such as SPDIF on 75 ohm BNC connectors, with another digital output configured as a DSP Input Pass-Through for connecting selected inputs for further processing. Additionally, it includes balanced and unbalanced analog outputs.

Audiophile quality throughout, the HDP-4’s balanced and unbalanced analog inputs are built around highly transparent analog-to-digital converters (ADCs) running at 24-bit/96kHz resolution. Two SHARC 32-bit floating-point DSPs provide internal processing resolution greater than 140dB, followed by 24/96 digital-to-analog converters (DACs). Nine separate power-supply regulation stages deliver extremely low measured distortion for fatigue-free listening.

And it also does the impossible by precisely integrating one or a pair of subwoofers into your system while supporting 2- or 3-way active speakers for those opting for DEQX XO™ Active configurations, now or in the future.


Measure (and correct) speakers first, then the room
In correcting the speakers—before the room—our comprehensive DEQX-Cal™ software generates correction filters for phase, timing coherence and frequency-response. Only then does DEQX-Cal measure from the listening area for room correction.


DEQX technology is unique
It corrects speaker frequency-response and timing errors by adjusting thousands of frequency groups, depending on your speakers’ measure­ments, so that they arrive at the correct time.

Traditional analog and digital EQ corrupts the timing coherence around the frequencies that they’re trying to equalize for volume. DEQX Processors slow down on-time and early-arriving frequencies so that slower frequencies can catch up.

That just can’t be done in the analog domain!

DEQX uses real computing horsepower to make that happen with a 240-megaflop, 32bit floating-point Digital Signal Processing Engine that essentially achieves zero distortion.


We’re DEQXperts
A DEQXpert agent can run the comprehensive DEQX Cal™ software for you on a secure, remote connection for a surprisingly affordable price. You’ll need a simple USB link to your PC (Windows compatible computer) using a measurement microphone and a broadband connection.

Or, if you prefer to calibrate it yourself, we can lend a hand via email or phone with tips and directions on getting the best from your setup.



Currently there are no reviews for this product.
Now almost impossible to find in the US, do you have the DEQX HDP4 in stock? Thanks, David

sorry no BR Pat

Hi, I'm interested but just not sure if it's the right solution. Do you have a returns policy if I'm unhappy with the unit? All the best, Mario

We don't have return on DEQX Br Pat

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