How does DEQX correct the room?

After the loudspeaker calibration phase is completed one or more room measurements are taken from the listening position to compensate for room acoustics. Multiple measurements are made to average calibration over a wide listening area, or a single sweet spot measurement provides reference-quality results for an audience of one or two. Four presets allow a variety of configurations to be saved.

If the bass is independently amplified, as is the case with powered subwoofers or bi-amplified speakers, it can be measured for speaker calibration from the listening position that provides better results as it includes room acoustics without compromising midrange clarity.

After speaker calibration is completed only minimal room calibration is required and that focuses mainly on bass frequencies. DEQX’s multiband minimum-phase parametric EQ can be automatically or manually set or manipulated for personal preferences. Four profiles can store different preferences for recall via the remote.

Why not use speaker designs and drivers that don’t need calibration?

Compared to a quality audio signal arriving at any loudspeaker’s terminals the measured output from the speaker will be between ten-to-one-hundred times worse in all relevant measurable categories depending on the loudness and complexity of the music being played.

Hopefully good passive speakers fall into the “only” 10-times worse category but even that’s based on static measurements that can’t measure dynamic degradation due to intermodulation distortion at higher volumes especially with complex orchestral music explaining the size and cost of the most expensive speaker systems.

The ear is sensitive to less than 1dB of volume at different frequencies yet a 6dB window is considered acceptable for a passive crossover speaker. We also detect timing inaccuracies on the order of microseconds that sound unconsciously unreal to us. An exciting you-are-there audio experience requires minimizing subconscious cues that tell us what we’re hearing isn’t real. All speakers benefit from active compensation such as DEQX provides as it minimizes the need for subconscious psychoacoustic reality checks.

Is frequency-response calibration related to phase/timing calibration?

The precise phase/timing calibration that DEQX pioneered goes hand-in-hand with its frequency-response calibration where frequency-response errors imply group-delay errors. Traditional EQ provides frequency-response compensation with a broad brush adjusting all frequencies in the vicinity whether they need it or not, nor does such EQ maintain linear-phase.

DEQX corrects phase and frequency response at thousands of frequencies only to the extent specified by the anechoic speaker measurements while maintaining or correcting phase accuracy. This simply can’t be done in the analog domain.

What is impulse response and what does DEQX do with it?

A speaker’s impulse response refers to the reaction of its drivers to an input as a function of time. One of DEQX’s main features is providing low-latency impulse response correction. This new generation of low-latency FIR/IIR digital signal processing was actually pioneered by DEQX for speaker calibration in the 1990’s.

The speaker’s measured impulse response defines its timing/phase and amplitude accuracy at any given frequency. DEQX uses Convolution FTT to redefine the speaker’s impulse response to correct the relatively dramatic errors it introduces compared to the more subtle errors of other component your system.

The audio signal is processed prior to the power amplifiers that drive the speakers so it is connected like a traditional equalizer but that’s where all similarities end. DEQX compensates for the errors measured in your speakers! This is very different from traditional equalization that’s unable to correct critical phase errors at different frequencies.