Huge Concrete speaker cabinets in foundation

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Hi Guys,

I need some help here. I've built lots of guitar amps and speaker cabinets but only a very few home audio speakers. I have never had the opportunity to do something like this but seeing as we are adding an addition to our house, I now have an opportunity to build some gigantic speakers right into the foundation of the studio downstairs. In this photo you can see the foundation walls which form two speaker cabinets. I now have the forms made for the top which will be 6" concrete also. Just outboard are two narrow "closets" which can be used as part of the speaker system if need be. I imagine I could pop a hole in the outer wall of each cabinet near the back and use the outer narrow closets to house the mouth of a large folded horn. I have been considering using an active crossover and triamping the system. The space between the two cabients will be used to house amps/crossovers, etc and probably a large screen TV before too long.

What goes into the large cabinets is up in the air. I can do anything that fits in this enclosure. My tentative plan is to mount a pair of 18s on each baffle which will attach to the front of the cabinet with angle iron frames which will be anchored to the concrete. What I use for mids and tweeters is completely open at this point. I'm looking for suggestions regarding the best drivers to use, how many, what kind of crossover to use, etc.

The room will be 16' x 24' with a 7.5' ceiling. I will be free to treat the room in any way I need to make it sound good.

Any ideas? Am I crazy? 😀

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Thanks, yes, I've seen that. I would like to have gone to that extent but I decided that it was just more time and money than I have currently.

Sorry about the 600k photo. It only takes 15 seconds to DL on my machine so I guess I forget some don't have fast connections.

OK, it is fixed now... only 180k.
 
Im not sure I understand the purpose of building the concrete closets. It looks to me like there is quite a bit of wasted space near the sidewalls and inbetween the closets. Can you draw a sketch of where the speakers are going?
 
In the middle is an open space for equipment. The speaker cabinets are on each side of that and are 40" wide by 44" deep. They are going to be 7.5' high. Then on the very outboard ends are two narrow cavities which can be used for folded horns if I decide that is useful. Otherwise I'll build a couple pull-out media closets to fill those cavities.

I'll see if I can upload a sketch of the tentative plan later.
 
Graydon said:
In the middle is an open space for equipment. The speaker cabinets are on each side of that and are 40" wide by 44" deep. They are going to be 7.5' high. Then on the very outboard ends are two narrow cavities which can be used for folded horns if I decide that is useful. Otherwise I'll build a couple pull-out media closets to fill those cavities.

I'll see if I can upload a sketch of the tentative plan later.

Make the cabinet holes a fraction deeper and you can load in a pair of LABhorns per side as well as some long J shaped midbass horns and HF horns. Yum.
 
Some have suggested the Lab horn but I'll suggest some alternatives that are cheaper and simpler.

Adire have a horn design for the Tempest which is about as simple as a horn can be. It can go up to 200 Hz so crossed that high you would want a stereo pair. IIRC it's about 0.6m wide x 0.9m deep x 0.9m high.

Bill Fitzmaurice also has a horn design (Tuba) based on a single driver.

To match the output you could do:

* 3 way with high efficiency drivers eg. Adire HE10
* array with hifi drivers

Since the Tempest horn will go quite high, you don't need to go further than 3 way. A simple solution would be an array with the CSS 4.5" XBL2 driver and you might even be happy without a tweeter, depending on your tastes.

Consider Ultradrive for the crossover and be ready to put in some room treatment and do some eq for room correction. Those concrete walls will have horrendous room modes!
 
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Hi Guys,

I need some help here. I've built lots of guitar amps and speaker cabinets but only a very few home audio speakers. I have never had the opportunity to do something like this but seeing as we are adding an addition to our house, I now have an opportunity to build some gigantic speakers right into the foundation of the studio downstairs. In this photo you can see the foundation walls which form two speaker cabinets. I now have the forms made for the top which will be 6" concrete also. Just outboard are two narrow "closets" which can be used as part of the speaker system if need be. I imagine I could pop a hole in the outer wall of each cabinet near the back and use the outer narrow closets to house the mouth of a large folded horn. I have been considering using an active crossover and triamping the system. The space between the two cabients will be used to house amps/crossovers, etc and probably a large screen TV before too long.

What goes into the large cabinets is up in the air. I can do anything that fits in this enclosure. My tentative plan is to mount a pair of 18s on each baffle which will attach to the front of the cabinet with angle iron frames which will be anchored to the concrete. What I use for mids and tweeters is completely open at this point. I'm looking for suggestions regarding the best drivers to use, how many, what kind of crossover to use, etc.

The room will be 16' x 24' with a 7.5' ceiling. I will be free to treat the room in any way I need to make it sound good.

Any ideas? Am I crazy? 😀

An externally hosted image should be here but it was not working when we last tested it.

Your ceiling height is too low for reasons having nothing to do with acoustics.
At this point a vaulted ceiling and steps for ground floor access is your only choice.
Basements with floors set 9-10' below grade, provide space overhead for a drop ceiling and utility runs. WHG
 
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