MTM baffle layout

[BDixon]

I've been searching and I'm starting to understand the reason for some of the baffle designs. What I'd like to know is why there hasn't been a MTM design where the mids are really close to each other and the tweeter is centered above them? A pyramid shape if you measured from the center of each speaker.

Just so everyone knows I'm ordering The Loudspeaker Design Cookbook so hopefully that will help while reading the forum. Also maybe I won't be asking such basic questions once it's here and I've had a chance to read it.

Thanks,
Brad

[JonMarsh]

With typical MTM crossover frequencies, you've have rather poor lateral dispersion. This is why most MTM center channel speakers don't work all that well.

OTOH, the Modula MTM uses low crossover frequencies, a special crossover network, and is close to what you describe.



The other problem is that a roughly square baffle, as the layout you're talking about might wind up with, has fairly poor baffle diffraction frequency response issues. Try simulating it in BDS, or something like LspCAD.

[PMazz]

If you're talking about a CC design, that's what I did (with Jon's blessing ). Since I had plenty of vertical height to work with, I just moved the midwoofs closer together and mounted the tweeter below them.




If you're talking about a vertical MTM, then you'd be talking about a TMM, and those are usually done as a 2 1/2 way to compensate for baffle step, for one thing.

How my doin Jon?

Pete

[JonMarsh]

You're on the money, MazzMan! :T

[BDixon]

Pete,
Yeah that was what I was talking about. Since I(and I'm sure many) don't really need woofers in their LCR's do to having subs, I just thought a setup like that would be used more. That was assuming it wasn't a bad design.

Brad