MTM vs TM , TMM ?

[donc]

What benefit if any does a MTM have over a TM or TMM considering SPL is the same ?
donc

[Jeff B.]

Re: MTM vs TM , TMM ?

The MTM has symmetrical vertical lobing. That doesn't mean it's always the best choice though. For example, a TMM tower may place the tweeter at a more optimum height and may be preferred in some designs.

[Greggo]

Re: MTM vs TM , TMM ?

I am a complete hack compared to Jeff B, but I would add for clarification (and hope I am not getting it wrong here) that symmetrical vertical lobing translates to less floor and ceiling reflections but also to a more constrained listening position, better for seated listener or being more on axis with tweeter and much less ideal for standing or sitting on floor. I normally find this less significant in practice however YMMV.

Even when overall SPL is the same, versus TM, I would assume that the MTM also offers greater dynamic range and efficiency, greater bass extension, lower distortion, less heat compression, etc... all the usual benefits of having a pair of drivers versus a single driver covering the same frequency range.

MTM vs TMM is more nuanced and a bit more beyond my knowledge base. In my experience as a listener I have tended to prefer TMM but that is just a useless generalization...

In terms of the three configurations you listed vs each other, I think it all depends on drivers, crossover points and system priorities.... any one of them can be a better option than the other two depending on the specific scenario.

[Chris Roemer]

Re: MTM vs TM , TMM ?

Two woofers don't really EXTEND the bass, they just increase power handling in (probably) the bottom octave (or 2).

[chrisn]

Re: MTM vs TM , TMM ?

The crossover for an MTM can be simpler/less expensive than a TMM, and is usually easier to implement.

[Wolf]

Re: MTM vs TM , TMM ?

The crossover for an MTM can be simpler/less expensive than a TMM, and is usually easier to implement.

Depends if the TMM is done as 2.5 way or 2-way as well.
Later,
Wolf

[Face]

Re: MTM vs TM , TMM ?

Depends if the TMM is done as 2.5 way or 2-way as well.
Later,
Wolf

A TMM that is not a 2.5 is not a good design choice, IMO of course!

[Paul K.]

Re: MTM vs TM , TMM ?

Don't agree with you, Face, but it is an IMO situation. MTMs generally have a bit forward sound to them that I don't like, which I assume is due to their symmetrical vertical lobing, and I definitely don't like them needing a taller cabinet to get the tweeter to a typical ear height.
Paul

A TMM that is not a 2.5 is not a good design choice, IMO of course!

[biff]

Re: MTM vs TM , TMM ?

Paul I don't see any real reason an MTM needs to be taller, one can angle the cabinet to align the two M/W's AC's and get the same outcome. They also can be monuted way up, and canted to the listener to get the arrivals matched. IMO, of course, ;)

[Face]

Re: MTM vs TM , TMM ?

Don't agree with you, Face, but it is an IMO situation. MTMs generally have a bit forward sound to them that I don't like, which I assume is due to their symmetrical vertical lobing, and I definitely don't like them needing a taller cabinet to get the tweeter to a typical ear height.
Paul

That forward sound can be addressed via voicing, a downward sloped treble can fix that.

[Deward Hastings]

Re: MTM vs TM , TMM ?

A TMM that is not a 2.5 is not a good design choice

If you're going to do 2.5 why not just do a 3-way? You'll almost always get cleaner mids and deeper bass . . .

[Jeff B.]

Re: MTM vs TM , TMM ?

A TMM that is not a 2.5 is not a good design choice, IMO of course!

I would strongly disagree with this statement. But I guess you wouldn't like my Testarossas or my Solstice speakers. Both began as 2.5 ways, but I ditched that because I got so much better results as a straight 2 way. In fact, I find these to be two of the best speakers I have done.

[Deward Hastings]

Re: MTM vs TM , TMM ?

The MTM has symmetrical vertical lobing.

In what circumstance (other than horizontal placement) does that give (what) benefit? The speaker is rarely placed symmetrically between floor and ceiling, so the "bounce" is going to be asymmetric in any case. Better, if one is going to add a third driver, to just go 3-way and reduce or eliminate the lobing issues altogether . . .

[Wolf]

Re: MTM vs TM , TMM ?

If you're going to do 2.5 why not just do a 3-way? You'll almost always get cleaner mids and deeper bass . . .

Doesn't happen often, but I agree with you on this, Deward. I've often contemplated doing a 2.5-way TMM, but when you factor in the driver cost, you might as well go 3-way. This is especially true if the drivers are quite expensive. Granted the xover gets more expensive, but it's worth it, IMO.

Mike- The forwardness of an MTM lobing pattern, IME, is not in the upper treble. At least that is how I read your reply.

Later,
Wolf

[Wolf]

Re: MTM vs TM , TMM ?

In what circumstance (other than horizontal placement) does that give (what) benefit? The speaker is rarely placed symmetrically between floor and ceiling, so the "bounce" is going to be asymmetric in any case. Better, if one is going to add a third driver, to just go 3-way and reduce or eliminate the lobing issues altogether . . .

You don't get as much bounce due to radiation pattern, and you also get a wider horizontal profile.
If you have low ceilings or hard floors, this can be a good thing.

Later,
Wolf