Meaning of "Q" in Denon 3805 EQ measurements

[pbarach1]

After running the Auto EQ procedure on the Denon 3805 receiver, the results can be displayed as a series of 8 equalization adjustments per speaker. These results are in 3 columns, Freq, Q, and Gain. Can someone please explain what "Q" means here, and what difference it makes when the Q is determined to be 0.1, 0.5, or 0.9??

Thanks for the explanation!

 

[j_garcia]

Q, normally called Q(ts), is the resonance curve for a speaker. I'm not sure exactly what it means on your receiver, but those figures are usually associated with the way a driver will react and what type of enclosure would be used for it:

As a general guideline, Qts of 0.4 or below indicates a transducer well suited to a vented enclosure. Qts between 0.4 and 0.7 indicates suitability for a sealed enclosure. Qts of 0.7 or above indicates suitability for free-air or infinite baffle applications.

My guess is that the Q function on the receiver is the type of curve it applies to the EQ function.

 

[WmAx]

After running the Auto EQ procedure on the Denon 3805 receiver, the results can be displayed as a series of 8 equalization adjustments per speaker. These results are in 3 columns, Freq, Q, and Gain. Can someone please explain what "Q" means here, and what difference it makes when the Q is determined to be 0.1, 0.5, or 0.9??

Thanks for the explanation!

Q, as you are referring to, is the relative bandwidth of that filter. For detailed information, please refer to:

http://www.bcae1.com/equalizr.htm

-Chris

 

[pbarach1]

Now I get "Q"

Thanks for posting that link; the graphs make it crystal-clear!

 

[Swerd]

After running the Auto EQ procedure on the Denon 3805 receiver, the results can be displayed as a series of 8 equalization adjustments per speaker. These results are in 3 columns, Freq, Q, and Gain. Can someone please explain what "Q" means here, and what difference it makes when the Q is determined to be 0.1, 0.5, or 0.9??

Q is a feature of a filter (either electrical or mechanical) that determines the shape of the filter's response around the frequency where a filter transition is taking place. Different Q values make for different shapes in the slope of a filter. Because the different filters will sound different, Q is a convenient way to identify the different shapes.

The attached picture shows the several different frequency response curves of high-pass filters with differing Q values. In this case they are mechanical filters created by different cabinet volumes and alignments for a subwoofer. When Q is low, the slope is more gradual but ultimately extends lower in frequency the the higher Q slopes. As Q gets larger, the slope is steeper and a hump appears above the 0 dB horizontal line for Q > 0.7.

 

[j_garcia]

Yep. That's how my sub was designed. The "normal" alignment uses a higher Q tuning, but this alignment is tuned to give better extension and smoothness at the expense of some output (and since there is plenty of output, that isn't a problem ).