HDP-Express II

Our entry-level HD-Active processor. For professional/OEM speaker development and DIY speaker builders.

4 digital inputs

2 analog inputs

HD-Active crossovers

Subwoofer integration

Room correction

Remote control

What's included

DEQX hardware unit

Your ordered DEQX hardware unit. Every single DEQX unit is individually tested before leaving the factory.

Calibration kit

A Standard Calibration Kit is included with every DEQX. The Reference Calibration Kit is an optional upgrade.

Software USB stick

Includes the DEQX-Cal™ installer, microphone calibration files, and a PDF version of the user manual.


The HDP-Express II doesn't have balanced or digital outputs and the analog circuits use slightly less "audiophile grade" components. In addition, the front panel buttons are not provided (use the remote control or DEQX-Cal).

The standard version of the HDP-Express II does not have the USB Audio input. This is because it is often used for speaker development and as a slave unit in more complex systems. However, you can add the USB input as an option when you order. It does have four digital and two analog inputs as standard.

The HDP-Express II has identical digital processing to the more expensive units, with the same features and specifications.

Yes! To use with conventional passive speakers, simply connect the power amplifier to the Mid/Full outputs.


Analog inputs and outputs
Balanced Unbalanced
Full scale input level 17 dBu / 5.5 Vrms 9.3 dBu / 2.25 Vrms*1
Input impedance 50 kΩ 50 kΩ
Full scale output level 10.8 dBu / 2.7 Vrms*1
Output impedance 75 Ω
Total harmonic distortion 0.0008%
*1. Factory default setting. Jumper-settable, see User Manual for full details.
Digital audio inputs
TOSLINK (optical) 24-bit, 44.1 to 96 kHz
S/PDIF (BNC) 24-bit, 44.1 to 192 kHz, 75Ω
S/PDIF (RCA) 24-bit, 44.1 to 192 kHz
AES/EBU (XLR) 24-bit, 44.1 to 192 kHz, 110Ω
USB Audio Asynchronous USB Audio Class 2, 24-bit, 44.1 to 192 kHz
Audio processing including HD-Active™
Crossover slope 48 to 300 dB/octave (linear phase)
6 to 96 dB/octave (Linkwitz-Riley and Butterworth)
Crossover frequency 22 to 18,340 Hz
Amplitude correction Better than 0.2 dB, typical (depends on measurement accuracy)
Group delay correction 0.5 ms, typical (depends on measurement accuracy)
Subwoofer crossover From 6 Hz, 24 to 120 dB/octave*2
Processing latency Typically 15 ms depending on filters, minimum 2.5 ms
Room EQ Seven or ten bands, 1 Hz to 48 kHz, −300 to +40 dB, Q 0.01 to 17
Preference EQ Three bands, 20 Hz to 20 kHz, gain to +/−9 dB, Q 0.5 to 10
DSP resolution > 140 dB
*2. Maximum available slope subject to filter delay limits.