MTM vs TMM, 2 WAY vs 2.5WAY sound quality question.

[marchel]

Hello to all,

I've been seeing alot of designs using MTM 2 way and TMM 2.5 way .

To those who've experienced both designs , Whether by listening to commercial speakers or DIY ones, What do you think sounds better between the two designs in terms of imaging , soundstaging and detail retrieval, Given than both use similar driver and similar baffle width?

Thank you

[MaVo]

i have not heard those besigns, but i assume an mtm will sound better since its more symmetric. the distance between each woofer an tweeter is smaller, so there will be less interference at crossover frequencies, thus a better sound.

i could be wrong, since i dont exactly know what the 0.5 way is.

[rj45]

I built a nice TM with a Dayton RS180 woofer and good tweeter.
Sounded real nice, but could not play very loud.
I added a 2nd RS180 for the .5 woofer, and found that the system could play much louder without distortion (expected), and that the upper midrange was much clearer (unexpected).

The textbook answer is that Intermodulation Distortion from a mid-woofer trying to handle both bass and mids is reduced, because the "regular" woofer has less excursion in a 2.5 way TMM system.

Downside is that there are not a lot of TMM 2.5 way designs to learn from, compared to MTM designs.

HTH
-Don

[Nemophyle]

i think that's really one of the things you have to test to know since the characteristic are just plain different

Also you have plenty of ways of designing boths wich will sound different.

I'd tend towards TMM 2.5 ways for myself, but i'd say it really depends on what you want to get.
TMM 2.5 ways is really fun cause it's an elegant design, if you're using the second woofer to compensate for BSC.
MTM 2 way is more special. It does have a more limited dispersion pattern in the vertical plane, wich can be a good thing

i guess the best thing would be to you to build some testboxes of both with same drivers to see what you like most

[newfinish]

mtm i like,but I really think it all depends on the woofers,if they are not efficent use mtm,you get more efficency,better overall.

[454Casull]

Originally posted by MaVo
i have not heard those besigns, but i assume an mtm will sound better since its more symmetric. the distance between each woofer an tweeter is smaller, so there will be less interference at crossover frequencies, thus a better sound.

i could be wrong, since i dont exactly know what the 0.5 way is.

Generally speaking, the bottom M in a TMM does not "pass over" to the tweeter, thus attenuating lobing.

[audiokinesis]

In my opinion matching up the radiation pattern in the crossover region is a good thing. So from this standpoint, a TMM 2.5-way would be preferable to the same drivers in an MTM configuration - but neither is what I'd do if the T is a direct-radiating dome.

Duke

[LineSource]

Marchel,

I would build a full frequency range 3-way TMW. I would try to get clever on the large bass cabinet design to minimize the apparent size. There are several good DIY 3-way designs that can be cloned in custom cabinets.

[marchel]

" but neither is what I'd do if the T is a . "

Well, I already ordered a pair of peerless HDS tweeters, But would'nt you use direct-radiating dome
In such designs?

Linesource,

My options on the midbass are still open, Cause I havent ordered midbass yet, I 'm thinking of usher 8945 A or P 7" woofers, 2 per channel ,.

OTOH , A 3 way with 10" woofer should be louder, I'm thinking about using Seas aluminum 10" woofer for a 3 way design and use the usher 7" as mid for its low distortion. but so far I havent seen a design that uses this combination and Madisound cannot design a crossover system for it , cause they dont carry usher brand.

[audiokinesis]

Marchel,

With a dome tweeter I'd do a TMW, probably using a 2" or 3" dome midrange. This results in less discrepancy between the on-axis response and the reverberant field response in the crossover regions, something that I believe makes an audible difference.

Duke