MTM’s or TMM’s: using sealed upper and TL (or similar) lower drivers?

[Andy G]

I know this sort of configuration theoretically introduces different “Q”, group delay , phase etc etc on the 2 “M” drivers if they are wired in parallel, but so does adding a coil on one of them in a 2.5, doesn’t it ??

Is this configuration really just a cabinet introduced 2.5 ??

How much does the different loading on the two drivers effect each of the drivers?

In an MTM, how much does introducing these anomilies effect the lobing, and other sound qualities?

and does the same apply if they are in a TMM configuration ?

Is there any simple way of electronically counteracting any group delay or phase problems this configuration might introduce??

So many questions, hope someone can answer !!

[planet10]

Originally posted by Andy Graddon
I know this sort of configuration theoretically introduces different “Q”, group delay , phase etc etc on the 2 “M” drivers if they are wired in parallel, but so does adding a coil on one of them in a 2.5, doesn’t it ??

I'll only sidestep this a bit... the 2.5 has the phase differences at the top of its range (and these can be mostly shielded from the FR driver by the cabinet if you mount the 0.5 driver on the back).

Different driver loading effects the bottom of the drivers range where the wavelengths are much longer.

To judge the magnitude of the effect you would have to add the complex FR (mag+phase) of the 2 together.

dave

[Jimmy154]

I seem to use this link a lot cause I don't know many websites, but it seems to be relevent http://home.hetnet.nl/~geenius/Auriga.html This dude made a 2.5-way with a sealed top woofer and vented bottom woofer.

[navin]

me think a aperiodic or TL bottom driver would pose less of a problem than a ported. just instinct.

another alternate is to TL both the drivers in indepenant TLs.

my definition of a TL here is a well damped TL which absorbs almost all of the back wave.

my 2 paise worth :-)