MTM or TMM

[LaraBingleHo]

I have read through most of the MTM TMM threads and still need an opinion or some help.

I have 4 of the SEAS M15CH001 with the stonehenge magnet and plastic cones, I want to use these with a pair of Raven R2's. What solution would give the most integrated sound, the MTM certainly looks better and looks like it should sound better, they will be on an OB.

The X/O will be by my DEQX absolutely no passive X/O.
Bass will be taken care of by my ATC drivers from my old ATC150's.

[Inductor]

Originally Posted by LaraBingleHo

I have read through most of the MTM TMM threads and still need an opinion or some help.

I have 4 of the SEAS M15CH001 with the stonehenge magnet and plastic cones, I want to use these with a pair of Raven R2's. What solution would give the most integrated sound, the MTM certainly looks better and looks like it should sound better, they will be on an OB.

The X/O will be by my DEQX absolutely no passive X/O.
Bass will be taken care of by my ATC drivers from my old ATC150's.

What you are used to see is the MTM, not the TMM, I guess. Maybe confusing with the WWMT, like the Wilson Audio Sophia. So if you want, and I would go with that, unless some other information is missing, you need a MTM to go with your woofer/s. Some concepts aesthetics are good also from WA, Focal or others.

Wilson Audio CUB (pic from)
Wilson Audio Specialties Alexandria X-2 (pic from)

[LaraBingleHo]

hi Inductor,
Thanks for the input. The SEAS are the same mid as was used in the Jamo R909, I originally wanted to copy or mimic that design. Unfortunately the 15" ATC drivers are not good for OB.
So far I have got a basic design using the seas and raven in MTM with the ATC in a sealed box with a 700 watt amp, it sounds fabulous. the ravens are driven by UCD 400ad and the mids with a modified Samick power amp. The deqx does a good job and the whole thing sounds quite nice, as soon as I can find enough parts I will try a TMM with the raven freestanding on the OB mids.

[rabbitz]

If using them in OB then MTM is the way to go. The best use for a TMM is a 2.5 way in a box (sealed, vented etc) and that arrangement is no good for OB.

For ideas there are a lot of OB MTMs here and have heard all of them.
Andy G constructions

[StigErik]

I'm using a MMT config in my OB's, but I XO much lower than possible with the Raven R2. I actually found that MMT was the better solution in this case, and I mean MMT, with the two mids above the tweeter. The advantages are that the mids come higher off the floor, pushing the floor bounce dip lower in frequency, and the two drivers couple somewhat to each other providing slightly less roll-off below the dipole peak. The inevitable dips in the vertical off-axis response with MTM config is also less of a problem with TMM or MMT.

[StigErik]

Originally Posted by LaraBingleHo

Unfortunately the 15" ATC drivers are not good for OB.

Why not?

[rabbitz]

The only OB that I've heard that doesn't use a TM or MTM is the Infinity RSII which uses 3 mid drivers to help address the roll off under Fp. The top and bottom mids use a different low pass crossovers to the centre mid which rolls off later and steeper than these.

Infinity RSII.... yum

Your use of the MM to provide less dipole roll off is interesting. Would there be an advantage by crossing of the 2 mids at different points on the low pass to flatten it further (i.e. top M earlier with a lower slope than the bottom M)?

[Syncroniq]

Hi,

A minor correction. The Jamo R909 uses a 12cm unit, not 15. I have asked Seas if it was possible to get a 12cm with hexadym magnetsystem, but no.

You should think about your listening axsis. The length from you to each unit. If both mids should be playing all the way up, i would go for a MTM as the phase would shift faster with a TWW (up and down).