I’m talking about closed enclosure tuning. Assume we’re going to design the three-way speakers utilizing a 12” woofer per cabinet. And the purpose is to obtain emphasized bass frequency (heavy bass speakers based on closed box configuration). Which way would you go for?
A) using high Qtc enclosure design, above 0.8 up to 2, and no attenuations on mid/high drive units (0dB)
B) using low Qtc enclosure design, below 0.58 down to 0.5, and employing some attenuations on mid/high drive units (such as -3dB to -6dB)
What are pros and cons between A) and B)?
A) using high Qtc enclosure design, above 0.8 up to 2, and no attenuations on mid/high drive units (0dB)
B) using low Qtc enclosure design, below 0.58 down to 0.5, and employing some attenuations on mid/high drive units (such as -3dB to -6dB)
What are pros and cons between A) and B)?
The bass tuning makes practically no audible difference compared to room/speaker placement/listening position.
On the contrary - big difference in the same room between Qtc=2 and Qtc = 0.5.
You are right. Qtc=2 will give a peaky and ugly one note bass response.
But considering sensible tuning the influence of the room is the dominant factor.
Ageed, a Qtc past 0.707 & thru 1.0 will be "uncontrolled" and prone to an undifferentiated sound. While it may be subtle, one will say it's "just not right". Only in an instance whereby one hears a "ideally damped" example will one be aware of the differences.
------------------------------------------------------------------------------------------------------------------------------Rick...
------------------------------------------------------------------------------------------------------------------------------Rick...
Blimey, yet another thread. 
A Qtc of 2.0 is so excessive it's not worth thinking about -to say nothing of the fact that tuning will be much higher & the box much smaller to the point you'd probably struggle to fit the driver into it.
Well, ignoring external factors, if your purpose is 'to obtain emphasized bass frequency...' then you've mostly answered your own question, because a well damped bass alignment by definition is always a well-damped bass alignment. If the midrange driver is capable of getting sufficiently low that the LF unit only covers the LF and not the lower part of the midband (and since in one of your other recent threads you were talking about dome mids, this is very unlikely), then you could suppress the midrange & HF levels relative to the LF sufficiently to cause an emphasis in the mid & upper bass, but a damped LF rolloff characteristic is what it is & probably won't chime too well with a desired excess.
A Qtc of 2.0 is so excessive it's not worth thinking about -to say nothing of the fact that tuning will be much higher & the box much smaller to the point you'd probably struggle to fit the driver into it.
Yes, the speakers will be used alone without subwoofers help.
So, according to last paragraph, you tend towards option B), using low Qtc box and add some attenuations to mid/tweet, right?
Lowest F3, aka maximally flat, is 0.707 (Butterworth). Lower Q boxes = larger for a given driver, with F3 rising. Whether it's excessively big or not depends (like 'optimal') on the design objective though. If it's lowest F3, then sure, Butterworth is what you need. If it's transient perfect / minimised overshoot, then it's 0.5, aka critically damped. Fastest settling to an impulse with only a little more overshoot is Bessel (0.577). But to a point these are academic as you need to take the room & placement into account, along with power-handling requirements & a bunch of other factors.
I read through this discussion, and thus far, the above entry is the closest to the truth. Not mean to offend any of the other contributions, but, more often than not, the room is 1) not only the dominant factor, but 2) often times overlooked when "theoretical" discussions are taking place. The ROOM is by far the single most influential component in a music playback system. The speakers will interact with the room, and accordingly, must "play with the room". As in, "harmony".
That being said, a super high Q system will seldom work in harmony, but a low Q speaker with a high Q room, might just be magic.
The bass shouldn't need to be compensating for a lack of warmth. If it is you have other problems. It's not intuitive. If you have good (proper) balance in and above the voice range, you can roll off the bass and still be satisfied.