'Assymmetric' bass tuning MTM and similar?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hello!

The topic might seem a bit vague, but the question is regarding speakers with more than one woofer. A good example would be a d'Appolito MTM. I did a quick test in a pair of Dali 104's (2x6,5" + 1" tweeter). It is the typical floorstander d'Appolito with both woofers in the same box.

I folded a piece of foam and stuffed it pretty hard just above the lower woofer, effectively dividing the box making two separate enclosures. In my ears this sounded better, tighter and more controlled bass. Some 'boominess' at certain bass notes was noticed before, but improved after.

I can say that before this I had already plugged the BR port, so that was out of the equation. To my preferences that was an improvement too, but dividing the box improved things even further. Better transient responce and lees 'boom' at some notes.
The woofers are now playing in two closed boxes with diffrent volumes. I guess one could add another port and retune the lengths to have them as BR again, but I generally prefer the bass from closed boxes.

I imagine a few reasons for the subjective improvement:
-Killed the standing wave top to bottom in the tall box. (box was not so well damped)
-Resonances for driver/box are offset, so the sum is more 'even' with woofers complementing each other in 'problem areas'.
-Maybe an easier load for the amp too, with impedance peaks att diffrent frequencies, giving a smoother summed impedance?

I've been trying to search for some wisdom around this, but I don't see a lot of info, and I don't see manufacturers/DIY:ers doing it, so there must be a reason for it? Why not tune parallelled woofers differently like in my example?
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.