In-Ceiling Speaker Crossover Issue

Hi everyone,

I just finished framing a drop down ceiling where I have added 4, Def Tech DT6.5 LCR speakers for Atmos. I was excited to 1) test a used Rotel amp I just purchased, and 2) to get Atmos running again, so I ran through the Marantz Audyssey setup prior to having the project finished. Audyssey set the speaker’s crossover to 250hz. Def Tech recommends 60hz.

Eventually, I’d like to add Rockwool to the ceiling by either placing cloth over the center area and putting the insulation above. OR, perhaps add drywall with various cuts in it (similar to PS Audio’s listening room’s sound absorbers/ diffusors)

My questions are: 1) Should I “box in” the Atmos speakers to create sort of a speaker cabinet for them inside the ceiling? If the “cabinets” are built and sealed correctly, could I expect better bass response from the Atmos speakers? And 2) Does anyone have experience treating a room for echo by mounting Rockwool in the ceiling, rather than on the walls? I have experimented moving treatments around the room with similar results, but they have always been on wall rather than on the ceiling. (And the ideal number of treatments is 8 - any less and echo still remains, anymore and the room sounds a bit too dead.)

Thank you all, again, for your help and I hope that everyone has a great 4th of July! (I have attached pictures below that can hopefully help everyone visualize this a bit better.)

I would expect the crossover to lower once you finish installing the ceiling as you alluded to you essentially have an open-baffle speaker now. Rather than build a box, I would just throw insulation around the speaker as it should also help improve its performance.

Def. Tech. is crazy to insinuate these can be crossed at 60Hz. My mains are full range, have two 12" woofers each and I still cross them at 80Hz. I am running a 9.2.8 set-up using Canton Plus XL.3 ( for the overhead. Just to give you an idea, these have a 5" driver (compared to your 6") and Audyssey recommends a crossover of 120Hz for me. I would expect a similar result for you when you finish the ceiling.

Sheesh - don’t ask for much, do you ; )

I was a former CEDIA-Certified installer, so this is the sort of thing I should be able to address. However, I’m a Marg and a Boulder Beer Chocolate Shake Porter in, so it’ll have to wait : )


sounds like a little would go a long way.


But, I don’t work impaired.

And frankly I had the notion that darker was stronger, but this isn’t. 5.9%.

1 Like

Apologies for the Thread Hijacking, J…peters…whatever.

All others, nota bene. Could be nothing.

J: Tried to respond to you, but seems like your response name isn’t there.

Guinness dispels that notion.


(extra letters so this will post)