damping factor

Leo, please explain Q factor. I don't know anything about it. Also, how does one learn what a particular speaker's Q factor is? I don't think I've ever seen that data/spec reported. Thanks

Amps with low damping factors (high output imp) will have a Hz response curve that may not be flat and IS effected and influenced by the speaker load. -i.e. - you don't know the amps Hz response curve until you hook it up and measure it with the load. In ohter words, if you change speakers, you are kind of changing amps too.- Different beast. :) This effects how loud the amp plays at different Hzs. This is one of the problems with many tube designs esp. SETS and why you need speakers with very flat Z curves.

Q is a speaker's "resonance peeking factor". There is a Q for the bare driver and another Q for the speaker box with the driver installed. This is a measure of the output db at the resonant frequency of the driver and/or box. It has nothing to do with an amp's damping factor OR the speakers impedence curve. Q is measured and used in basic calclations for designing the speaker box volume and is usefull predicted bass responce.

I'm not sure I CAN explain speaker 'q' except that it is a design choice made and involves the TS parameters of a driver....the woofer....and box size and port tuning...where needed.
Critically damped is a value of .707 (sine of 45...coincidence?) while higher numbers result in bloated.....thick or boomy bass. The typical tuning of some of the old 12" 3-way monitor speakers of old was higher and I can't think of an example of a lower 'q' speaker, though they may exist.

Somebody that knows more / better can chime in, but as near as I can tell NO high damping factor can save a speaker with hi 'q'.

The parameter in question....please read....is QTc.......

http://www.bcae1.com/spboxad2.htm

or this discussion...look to 3rd or 4th post down.

http://www.hometheaterforum.com/forum/thread/135679/what-does-qtc-mean

I don't know if this helps. My personal take-away is NOT to depend of damping factor to 'control' a woofer. Whoever wrote that any value over 20 (atmo?) is fine may be on to something. Fullrange Single Driver speakers may benefit from low damping and produce the appearance of fuller bass....but this is conjecture on my part

And Bif, you will NEVER see this number reported. 99% of even those who are in the audiophile camp wouldn't know 'Q' from a bag of beans.....While, on the other hand, the speaker builder, DIY crowd make use of it every day in the design of the bass part of their homebrew efforts.

Thanks, Elizabeth, I owe you one....my login is WAY flakey.....

Does this help or hurt?