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DEQX release HDP-4 and HDP-Express II; HDP-3 and HDP-Express discontinued

by Nyal Mellor May 21, 2012

DEQX have released their new HDP-4 and HDP-Express II digital crossover / loudspeaker / room correction processors. The first production run is expected to be completed end of May 2012 with Acoustic Frontiers receiving our initial inventory shortly afterwards. Both are now available.


Key takeaways:

  • The HDP-3 and HDP-Express are both discontinued. We had a few units left but are now completely sold out. DEQX do not have any of the old units left either; production is switched over entirely to the new units.
  • The entry level DEQX processor, the HDP-Express II, is now $2995 $3495 retail, up from the $1950 of the original HDP-Express.
  • Both processors are based on all new main circuit boards with 32/192 DACs.

The flagship HDP-4 offers a number of refinements over the outgoing HDP-3 including:

  • Four 24/176 and 24/192 capable digital inputs, including an optical and SPDIF on BNC. Note the internal DSP still runs at 24/96. We don't know of any digital processors that run at 24/192...
  • Balanced outputs as standard. There is still an option for a Jensen Transformer balanced output board at the same price as previously ($988). Jensen option discontinued.
  • Digital outputs as standard, all on BNCs, including a 'pass through' output. The pass through output is a god send for those who want to run a four way, as it allows you to use a cheaper DSP crossover or DAC for a subwoofer channel without having to add an additional DEQX unit
  • All new main circuit board with 32/192 DACs
  • Optional 24/192 USB plugin board will be available later in 2012

DEQX HDP-4 back panelThe HDP-Express II differs from the HDP-4 as follows:

  • Simplified front panel, available only in black and made out of 6mm aluminum, with no front panel volume or profile selection buttons
  • Switching power supply, as opposed to the lower noise linear power supply in the HDP-4
  • No balanced outputs or balanced output option
  • No digital outputs or digital output option
  • Lower grade op-amps
  • Ceramic decoupling capacitors used in the digital section as opposed to higher grade film in the HDP-4

The calibration kits are unchanged, with three mic options available: the standard including a Behringer ECM8000 and two Earthworks units, the M23 and M30.

The HDP-4 and HDP-Express II are now available for pre-order. Please contact Acoustic Frontiers to discuss these new units today!

Nyal Mellor
Nyal Mellor


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Nyal Mellor, Founder, Acoustic Frontiers

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  • Fairfax, Northern California, USA

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