DEQX, a company from Australia reknowned for their pioneering use of DSP loudspeaker correction, have released a new product called the HDP-Express.

Acoustic Frontiers is proud to be selling the DEQX HDP-Express and DEQX HDP-3 from our ecommerce store. HDP-Express and DEQX HDP-3 are now discontinued and replaced with the HDP-4, HDP-Express II and Mate, see the DEQX page on our website.

The HDP-Express ($1950) provides exactly the same digital room correction, digital loudspeaker correction and digital crossover functionality as the twice-as-expensive ($3995) HDP-3. The concessions that have been made are to replace the linear power supply with a switching unit and to implement a lower cost volume control system.

The DEQX HDP-3 and HDP-Express meet all of our criteria for a room correction product (see the table below for more details). In addition they provide significant opportunities to further improve your system through use of digital crossover and digital loudspeaker correction.

Acoustic Frontiers is an authorized dealer for DEQX. HDP-Express and DEQX HDP-3 are now discontinued and replaced with the HDP-4, HDP-Express II and Mate. If you have any questions on this awesome unit please get in touch!

Note that for home theater TWO HDP units in a special 'master/slave' mode must be used to provide correction of the LCR and surround loudspeakers. The DEQX units would be connected between pre-processor and power amplifier.

In case you missed the detailed explanation of the functional criteria that I am reviewing room correction products against please see here and here. If you didn't read the detailed and comprehensive introduction to room correction, see this article.

The functional criteria that we reviewed the DEQX products against have been shortened to fit into the table. Here is the interpretive legend:

• Choose Freq --> Must not apply correction filters above the transition frequency OR must allow the user to switch off room correction above the transition frequency. Since all these devices are designed to be used on subwoofers only (which are typically used only below 80Hz-100Hz) they meet this criteria by default.
• Choose Target --> Must allow the user to choose a target frequency response
• No A/D or D/A --> Must not perform an un-needed analog to digital or digital to analog conversion.
• Auto Measure --> Must provide automatic measurement and correction filter generation capabilities

If you didn't read the detailed and comprehensive introduction to room correction, see this article.