DEQX active linear phase digital crossovers

In addition to detailed correction of loudspeaker frequency response, phase and group delay timing errors, DEQX’s ‘active’ implementation also provides extremely steep linear-phase crossovers to 300 dB/octave.

This compares with today’s ‘passive’ speaker crossovers that are typically 6 to 12dB/octave, with no phase correlation, no ability to correct frequency response errors and usually unable to correct even gross timing errors between drivers.

While "going active" offers some improvement over a passive setup, the listener will still miss the full benefits of a digital linear phase crossover, as the following diagrams explain.

Figure 1: Loudspeakers with passive crossovers use a single amplifier to drive them. Its high power is only roughly separated into high and low frequencies for tweeter and woofer using up to 12dB /octave filter slopes. Note that high frequencies (blue) sent to the tweeter also contains significant levels of low frequencies (red) that cause tweeter distortion. Yet the woofer also receives significant highs’ that it’s large diameter must ‘beam’ narrowly towards the sweet spot while unable to product high frequencies as cleanly as the tweeter. This results in ‘crossover distortion’ and unnatural dispersion over several octaves. Additional distortion is caused by passive components that present complex loads to the amplifier.
Figure 2: In a normal active loudspeaker design, such as those oftern used by audio professionals, each driver has its own amplifier. This allows the crossover to run at ‘Preamp’ (rather than amplified) signal levels. This enables steeper crossover slopes, being typically up to 24dB/octave, which provide better separation of highs and lows going to the drivers. However, these loudspeakers are still NOT able to maintain ‘linear phase’ due to each drivers inherent errors.

Figure 3: DEQX ‘active’ crossovers correct phase and frequency response for each driver. Note the far steeper crossover slopes than ‘normal’ active (Figure 2 above). Steep crossovers, up to 300dB /octave, quarantine energy to the ‘comfort zone’ of each driver.The results include:

• Increased power handing
• Improved dynamics
• Better dispersion and a wider sweet spot
• Elimination of interaction between drivers while maintaining phase coherence.

The resulting frequency response and group delay behaviour is corrected to a level that is impossible to achieve with normal passive crossovers, or even with normal active crossovers.

Figure 4: DEQX allows various configuration options. Popular 2-way configurations for Stereo and Home Theatre are accurately integrated and time-aligned with sub-woofers.

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