Multi talented Audio processor by DEQX; manufacturers of leading-edge preamp processors providing speaker calibration and room compensation.
Entry-level HD-Active processor by DEQX. For professional/OEM speaker development and DIY speaker builders.
DEQX hardware unit
Your ordered DEQX hardware unit. Every single DEQX unit is individually tested before leaving the factory.
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.
What is the difference between the HDP-Express II and the HDP-4?
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).
Does the HDP-Express II have a USB Audio input?
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.
Is the audio processing any different?
The HDP-Express II has identical digital processing to the more expensive units, with the same features and specifications.
Can I use it with full-range (passive) speakers?
Yes! To use with conventional passive speakers, simply connect the power amplifier to the Mid/Full outputs.
The Express II packs much of the new technology of our flagship HDP-4 Preamp Processor in a new, extraordinarily cost-effective design.
The Express II uses professional-grade components and power supplies but we've kept the price of the Express II down. By moving the front-panel controls to the remote while deleting the HDP-4's balanced analog and digital outputs for a simpler chassis.
Like its predecessor, the Express II provides DEQX InlineTM correction for your existing speakers, room and media. Plus, it does the impossible and precisely integrates one or a pair of subwoofers.
The Express II also supports 2- or 3-way active speakers for those opting for DEQX XOTM Active configurations with DEQX's linear-phase crossovers, now or in the future.
The Express II offers four hi-resolution digital inputs, accepting sample-rates including 24-bit/192k and two analog inputs (balanced XLR and single ended RCA) with 96k analog-to-digital conversion.
Measure (and correct) speakers first, then the room
In correcting the speakers-before the room-our comprehensive DEQX-CalTM 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.
Analog inputs and outputs
Full scale input level
17 dBu / 5.5 Vrms
9.3 dBu / 2.25 Vrms*1
Full scale output level
10.8 dBu / 2.7 Vrms*1
Total harmonic distortion
*1. Factory default setting. Jumper-settable, see User Manual for full details.
Digital audio inputs
24-bit, 44.1 to 96 kHz
24-bit, 44.1 to 192 kHz, 75Ω
24-bit, 44.1 to 192 kHz
24-bit, 44.1 to 192 kHz, 110Ω
Asynchronous USB Audio Class 2, 24-bit, 44.1 to 192 kHz
Audio processing including HD-Active™
48 to 300 dB/octave (linear phase)
6 to 96 dB/octave (Linkwitz-Riley and Butterworth)
22 to 18,340 Hz
Better than 0.2 dB, typical (depends on measurement accuracy)
Group delay correction
0.5 ms, typical (depends on measurement accuracy)
From 6 Hz, 24 to 120 dB/octave*2
Typically 15 ms depending on filters, minimum 2.5 ms
Seven or ten bands, 1 Hz to 48 kHz, −300 to +40 dB, Q 0.01 to 17
> 140 dB
*2. Maximum available slope subject to filter delay limits.
Payment & Security
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.