Effects of an MTM arrangement on frq response?

[Osafune]

I was just wondering what the benefits or drawbacks are over a regular 2=way design.

How does the placement of the two midwoofers effect the frequency response and also dispersion characteristics?

Any knowledge you could share would be greatly appreciated.

Does this kind of arrangement limit the vertical dispersion?
What amount of sensitivity will be gained by using two drivers instead of just one? 3db?

Also if anyone can direct me to a site with good information on this or a related subject please do so.

Thanx!

 

[GM]

IIRC, this should give you a pretty good idea of what's going on:
http://www.birotechnology.com/articles/VSTWLA.html

GM

 

[Osafune]

Thank you I'm much obliged.

 

[navin]

i built a few MTM thinking that hte cylindrical wave front etc.. would be better but i still seem to prefer a standard 2 way dont know why. cant put my finger on it though.

 

[MarcelvdG]

I don't know if this helps, but as far as I recall, Joseph D'Appolito shows in his AES preprint that the main lobe of an MTM configuration for frequencies near the cross-over frequency is never tilted, regardless of what type of cross-over is used. (For a normal two-way system with one woofer and one tweeter, you need to use Linkwitz-Riley filters and to ensure that the drivers have roughly the same phase shift near the cross-over frequency to prevent a tilted main lobe.)

According to D'Appolito, the off-axis response in an MTM configuration is best when an odd-order Butterworth crossover is used and the vertical distances between the drivers are minimised. In order to get a flat on-axis response with a Butterworth cross-over, you again have to look out for driver phase shift differences.