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DEQX HPD3 Crossover DEQX HDP-3 High Definition Digital Preamp Processor with Room Correction, Speaker Measurement, and Speaker Correction Complete with remote control, manual and ECM 8000 measurement microphone. I used this as an electronic crossover for my 3 way tri-amped speakers. Wonderful adjustment for crossover points and slopes plus so much more. I have just gone to active speakers so no longer required. Condition: Excellent Payment Method: EFT, PayID, cash on pickup Region/State: (QLD) Queensland/Australia By Ladder413 0 Comments AUD $2,000 Date: August 26, 2025Aug 26
# DEQX HDP-4 at AUD $2,000 – Buyer Notes
At AUD $2,000, this is a solid buy if the unit is genuinely in good working order. The HDP-4 originally retailed around AUD $4,300, and used examples typically move between AUD $1,000–$2,500 depending on condition and completeness. You're at the higher end of that range, so condition really matters here. If it's clean, fully functional, and includes the microphone kit and USB input module, this pricing sits fair-to-reasonable. However, the HDP-4 is now a legacy product (discontinued years ago), so you're betting on long-term support and parts availability.
Before committing, verify the unit powers on cleanly and cycles through its menu without glitches—older digital processors can develop capacitor issues. Confirm the microphone calibration kit is present and functional; it's essential for the room-correction magic and expensive to replace separately. Ask the seller for proof of recent use and whether it's been recapped or serviced. Check that all input/output connectors are clean and the USB module (if included) works reliably, as these can be finicky on older gear.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
DEQX is an Australian digital audio specialist founded in the mid-1990s as Clarity EQ Pty Ltd and formally established in 2001 by Kim Ryrie, the legendary co-founder of Fairlight Instruments. Ryrie's pedigree in pioneering digital audio technology—Fairlight revolutionized music production in the 1980s through its groundbreaking sampling instruments—directly shaped DEQX's engineering philosophy and access to world-class design talent. This heritage positions DEQX as a company with deep roots in digital signal processing innovation.
DEQX specializes exclusively in digital pre-amplifiers and audio processors engineered around speaker calibration and room correction. Their current Gen-4 lineup features integrated systems like the LS200 and flagship pre-amplifiers such as the Pre-8, all built on multi-core 64-bit processing architecture. Rather than traditional component categories, DEQX's core offering centers on digital correction technology that compensates for loudspeaker distortions and phase errors, reconstructing audio signals with microsecond precision to achieve time-coherent reproduction.
DEQX occupies the high-end niche market, targeting discerning audiophiles who prioritize measurement-based accuracy and digital processing sophistication over conventional analog approaches. Over 95 percent of their products are exported globally, reflecting strong international recognition among serious listeners. The brand has cultivated a reputation as a specialist tool for those viewing speaker calibration as essential to achieving reference-quality sound, positioning itself distinctly within the premium segment where technical innovation and measurable performance command premium pricing.
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