MTM or MT speakers

[Landroval]

If you have to have a big multiway then 2 small mids (2-3") with a small tweeter in an MTM, flanked by woofers (with a low XO) would be the way to go.

I think most "Home THX Ultra" LCR speakers use this kind of approach. Basically it's a vertical MTM with two low-cut woofers on the sides.

 

[ocool_15]

I've been looking at doing the exact same thing! 2 woofers will go lower then a single. I have also seen tmm designs that have the 2nd one crossovered alot lower (~200Hz)and there just to extend the low end in a small box. I was looking at doing a MTMW but I think ill end up doing a tmw 1", 2.625" 5.25".

Any advantage in soundstage or upper(650Hz-5kHz) response?
~~~~~~~~~~~~~~~~~~~~~~
Hi,
You should be aware that 2 woofers don't actually "go lower" than a single woofer, ... but it really doesn't go any lower, just louder in the lowest frequencies.
Best Regards,
TerryO

I thought that if one had say -3dB point of 55Hz that if you had 2 of them they would only be -1.5dB at 55Hz so the 3dB point would be lower. Box size would be double that of a single driver of course.
Some quotes from parts express:
" ... and deep bass that does not "boom" or sounded muddied. Deep bass often comes at the expense of high group delay when using inexpensive speakers, due to the large box volume necessary to achieve a low tuning frequency. In this case, the enclosures are tuned to 36.75 Hz with an enclosure volume of just 31 liters. "
"The output levels and bass capabilities (down to the low 40's) of the twin 7" woofers is impressive. "

 

[planet10]

it's a vertical MTM with two low-cut woofers on the sides.

exactly.

dave

 

[planet10]

I thought that if one had say -3dB point of 55Hz that if you had 2 of them they would only be -1.5dB at 55Hz so the 3dB point would be lower. Box size would be double that of a single driver of course.

Nope. 2 drivers in 2x the volume will have the same cutoff but are 3 dB more efficient.

dave

 

[Salas]

6 db more efficient not 3 dB

 

[Salas]

''sensitive'' to be exact

 

[planet10]

only 6 dB more sensitive if your amp can deliver the current at the lower impedance you get if you wire the drivers in pararallel.

I never talk about sensitivity (i consider it only in general use because the marketing guys can deliver larger numbers) ... efficiency goes up 3dB whether you wire in series or pararallel. Any extra is from the amp not the speakers.

dave

 

[Salas]

I know your approach and I agree. But the vast majority with ss amps is going to observe more than 3 dB final spl increase when wiring 2 woofers in parallel and we have to be more elaborate in explanations unfortunately. I am a fan of tubes, bipoles and 16 Ohm loads anyway.