Building an MTM design as a MMT instead?

Hi all,

Very interested in the Overnight Sensation design to use as nearfield monitors in my home DJ studio. I like the idea of the extra bump in output and extension the second driver in the MTM version would provide vs the basic MT, but given the way I would be using/placing the speakers I would greatly benefit from the tweeter at the top at the top of the cabinet with both of the mids below, like you would see on a floorstanding speaker. This would make it far easier to get the tweeters better aligned at my ear level given the short distances from the listening position (3-5 feet). Could there be any serious detriment to the response if I reconfigured the drivers in this way, though?
 
That depends on the path length differences between the drivers and your ears and the crossover frequency. When your ear is a distance d from the tweeter and the lower midrange speaker is h below the tweeter, the path length difference is sqrt(d2 + h2) - d. How much phase error does that cause at the crossover frequency, given a speed of sound of about 340 m/s?

Edit: I gathered from the first post that it is a two-way loudspeaker, but understand from the second post that that's incorrect.
 
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That depends on the path length differences between the drivers and your ears and the crossover frequency. When your ear is a distance d from the tweeter and the lower midrange speaker is h below the tweeter, the path length difference is sqrt(d2 + h2) - d. How much phase error does that cause at the crossover frequency, given a speed of sound of about 340 m/s?

Edit: I gathered from the first post that it is a two-way loudspeaker, but understand from the second post that that's incorrect.
Edit: I assumed it was 2 way with 2 drivers on the low pass leg but apparently it's a 2.5. Still learning.
 
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Sorry, it seems I missed some pages.

No, an MTM can be 2.5 way but normally it is a Butterworth 2 way, and sometimes a LR 2 way.

Overnight Sensation TM - https://sites.google.com/site/undefinition/bookshelf-speakers/diy-overnightsensations
Overnight Sensation TMM - https://ewhmz54ghhe.exactdn.com/wp-content/uploads/2019/01/Overnight-Sensation-TMM-Tower-Writeup.pdf
Overnight Sensation MTM - https://sites.google.com/site/undefinition/bookshelf-speakers/overnightsensationmtm
Ah. Those links are very helpful! I tried searching but I didn't come across any of those. Thank you!
 
So I'm still struggling a bit. Paul makes the design work as a TMM but has completely changed the dimensions and the crossover. I'm not sure if he did that because he assumes that the point of doing a TMM is to make it a floor standing speaker instead of a bookshelf, or because the change in configuration necessitates it. The original MTM dimensions suit my application better but if shuffling around the drivers is going to whack out the sound then it's obviously not worth it.
 
You may be able to navigate the range of components if you look at the issues behind them...

The tower is a 2.5 way which has to account for some of it.

Two mids playing at once in the MTM would account for less midrange (narrow directivity) so maybe chose a little boost there? As well maybe the MTM needed a phase shift?

Then there's the baffle compensation for the different uses of a bookshelf/tower.
 
So I'm still struggling a bit. Paul makes the design work as a TMM but has completely changed the dimensions and the crossover. I'm not sure if he did that because he assumes that the point of doing a TMM is to make it a floor standing speaker instead of a bookshelf, or because the change in configuration necessitates it. The original MTM dimensions suit my application better but if shuffling around the drivers is going to whack out the sound then it's obviously not worth it.
You could always go straight to the horse's mouth, and ask Paul directly. He is active on the PE Tech Talk forum.
 
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