DEQX Introduces Audiophile HDP-Express II

DEQX Introduces Audiophile HDP-Express II

9/26/2012Sydney, Australia  -  DEQX (say it like DEX), manufacturers of leading-edge Preamp Processors providing speaker correction, crossover and room compensation, introduces the HDP-Express II for two-channel audiophiles looking to upgrade their system in a BIG way!

Master the Art of Timing

DEQX processors correct the distortion that all speakers make – electro-mechanical devices that they are – with room compensation an added extra. DEQX processors are unique in correcting frequency-response errors as other units do but also critical timing errors by adjusting thousands of frequency groups to arrive on time. 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. Everything becomes more physical, dynamic and precise, open and powerful making it much easier to be involved with your music and video. . .Read more here

Introducing the HDP-Express II

The HDP-Express II packs much of the new technology of our flagship HDP-4 Preamp Processor – now shipping! – in a new, extraordinarily cost-effective design. Like its predecessor the HDP-Express II provides DEQX Inline™ correction for your existing speakers, room and media. Plus it facilitates precise integration of one or a pair of subwoofers. The Express II also supports 2- or 3-way active speakers for those opting for DEQX XO™ Active configurations now or in the future.

The Express II uses professional-grade components and power supplies while the HDP-4 is outfitted with audiophile-grade parts throughout adding a linear mains power supply. DEQX also kept the price of the Express II down by moving all front-panel controls to the Remote and deleting the HDP-4’s balanced analog and digital outputs for a simpler chassis.

The MSRP for the Express II is $2,950 USD while the HDP-4 remains $4,950 USD, both available now. Frankly it’s a huge value considering the many features of our premier HDP-4 – including the powerful Remote – found in the HDP-Express II.

Measure (andCorrect) Speakers First Then the Room
Measuring the speakers first – rather than the room – our comprehensive DEQX-Cal™ software generates correction filters for proper phase, group-delay and frequency-response all of which varies with frequency! The HDP-4 and HDP-Express II actually correct the typically large timing errors that speakers always produce and returns frequency-response accuracy to that of the original recording. Only then does DEQX-Cal measure from the listening area for room correction.

DEQX technology is unique! It corrects frequency-response and timing errors by adjusting thousands of frequency groups to one degree or another depending on your speakers’ measurements so they arrive at the correct time. 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 followed by judicious room compensation. Everything becomes more dynamic and precise, open powerful and palpable, making it much easier to get involved with music and video.

How unique is DEQX? Traditional analog and digital EQ corrupts timing coherence around the frequencies they’re trying to equalize for volume. DEQX Preamp Processors slow down on-time and early-arriving frequencies so slower frequencies 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 floating-point Digital Signal Processing Engine that essentially achieves zero distortion.

DEQX XO Active speaker architecture features linear-phase crossovers driving separate amplifiers that drive individual speaker drivers. The steep and truly linear-phase crossovers dramatically improve resolution at normal and higher volume by limiting crossover and compression distortion without the usual phase errors introduced by traditional crossover filters. With each driver operating in its most linear range you’ll enjoy a more natural, coherent sound.

The Forensic Tone Control!

The DEQX Remote features Standby, Profile Select, Volume, Mute and Input Select, and what must be the world’s most powerful tone controls. Its three bands include Lo, Mid and Hi with up/down buttons for +/- 1dB adjustments (-9dB to +9dB). If you get lost there’s a ZERO button and another that clears all three bands of EQ.

The bass band defaults to below 100Hz with a shallow slope, while the highs default to above 3kHz. However both frequency and slope are also user definable on the fly – there’s a table on the back of the remote to help you out.

While Lo and Hi settings are shelved, the Mid band is fully parametric and adjustable from the remote! Although it’s called the Mid-EQ channel because of its default midrange setting, its center frequency can be set in octaves from lowest bass to highest highs then fine-tuned by moving frequency up or down by semitones. Bandwidth ranges from one semitone (1/2th octave) to four octaves wide!

The Forensic Tone Control is detailed enough to allow effective room EQ by ear alone as the controls provide instant adjustments that don’t overwhelm the sound like traditional tone controls or wind up sounding overly-detailed like some pro-world parametric EQ.

Use the powerful Forensic Tone Control as a Media Corrector by simply choosing a Preference EQ for low listening levels, particular recordings or record labels, and save it to one of 99 presets for instant recall!

We’re DEQXperts! 

Contact us for installations using our surprisingly affordable DEQXpert™ services. We can come to you or run the comprehensive DEQX Cal™ software for you on a secure, remote connection. You’ll need a simple USB link to your PC (or Windows on a Mac platform) using our calibrated microphone and a broadband connection.

If you opt for a remote setup a DEQX Agent guides you through the process explaining as much or as little as you’d like. DEQX-Cal measures your existing system in fine detail and builds filters that correct the inevitable phase and balance problems that muddy the sound and collapses the sense that you’re inside the action. If you want to install yourself we can lend a hand online with tips and directions on getting the best from your setup. You can also talk to us about using DEQX Cal yourself… you can do it!

Moving Up 

Our valued customers won’t be left out in the cold when we introduce new products. DEQX always offer generous trade-up specials. Feel free to email your unit’s serial number to for a quote. The price depends on a number of factors including age, model and type. Of course you can always keep your HDP-Express or HDP-3 for surround speakers and add a HDP-Express II or HDP-4 for the front! You can set up with multiple DEQX Processors for a surround system supporting all configurations or just a single stereo unit correcting the left and right fronts for an impressive improvement at minimal cost. All DEQX correction files are compatible with these two new processors.


If not working with a DEQX Agent in your home or studio and want to measure and correct the speakers and room yourself or via remote connection to a US Agent you’ll need either the Standard Calibration Kit or Reference Calibration Kit. For the highest performance speaker correction DEQX recommends the Reference Calibration Kit with Earthworks microphone. The Beringher microphone with the Standard Calibration Kit has a 20kHz top-end correction limit but the HDP-3 passes up to 40kHz. The HDP-4 also comes with DEQX Cal Software and Firmware.

 The Method

Other “room correction devices” simply adjust amplitude response – uneven output at different frequencies – to offset room modes. But they don't address phase or group-delay timing issues that exist in all real-world speakers. . .Read more here

DEQX works with whatever you’re listening to and results in startling improvements. Modestly-priced stand-mounted speakers to top-tier audiophile brands all sound better with DEQX!