MultEQ XT at upper frequencies

It seems the main value is how MultEQ XT applies both time- and frequency-domain corrections to low frequencies. This makes some sense as room modes and geometry can lead to pretty bumpy bass response.

What does MultEQ XT do at mid- (say ~300Hz) and high-frequencies (above 2K)? Is it mainly frequency response shaping to the target curve? You can't do much time-domain correction at high frequencies, but 300Hz is low enough to do something. How precise is this adjustment, are there typical performance expectations like +/-1 dB within 1/10th octave bands? Obviously the smoothness of the underlying speaker has something to do with this.

2-way speakers often have an abrupt directivity change at crossover, which results in changes to the direct/reflected balance. Waveguides and multi-ways can help, but typically there is still some change at crossover. Can MultEQ XT do anything to address this? Presumably weighting the number of samples on-axis vs. off-axis could "tune" how hot the center seat is relative to the side seats.

I personally do not think it is very audible, but does MultEQ XT try to improve time alignment between between drivers in a multi-way system?

I've mentioned MultEQ XT above, but what are the differences between the different levels of MultEQ at mid- and upper-frequencies?

Gl Ok -
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3 Comments

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    Audyssey Labs

    MultEQ filters operate in the time domain so octave band notation doesn't apply.  Impulse responses are measured at multiple locations and then they combined by weighting the most significant problems first.  These generally happen in the lower frequency range and so higher resolution is applied there.  We don't publish the filter resolution, but the relative resolutions are shown here for the various flavors of MultEQ.

    Because the filters operate in the time domain, any phase issues that arise from misalignment of drivers will be addressed.  Obviously the results will be even better if we are allowed to control the delay of each individual driver, but this doesn't happen in home speakers.  Our automotive customers do take advantage of that portion of the algorithm.

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    Gl Ok

    Hi Chris,

    Thanks for the explanation. I don't know if it is fair to mention competitive products, but it seems the DEQX processors do something similar to MultEQ. However DEQX can correct upper frequencies (if desired). It understands the net phase and amplitude response of a multi-way system, and can correct anechoic speaker response separately from room correction. There is a claim of +/- 0.5 dB response correction -- though it is kinda meaningless without knowing smoothing or averaging bandwidth.

    http://www.deqx.com/technology.php

    Now I realize that DEQX is a very high-end product, and I also appreciate that the biggest benefit might be taming room modes at low frequencies. My question is more that there seems to be an opportunity to apply mid-band and higher corrections as part of MultEQ, and I'm wondering if that happens vs. just the bass corrections.

    Anyway, it's the model year switch and just ordered a "last year's model" Denon AVR-2312ci at a nice discount. If I have time, I'll try to measure quasi-anechoic response for the fronts with and without MultEQ and then I'll know what it does (at least for my setup).

    Thanks, Glen

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    Audyssey Labs

    MultEQ corrects the full frequency response, not just the low frequencies. 

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