Concrete IB subwoofer

[Ile]

Didn't find many IB builds around here, so I thought some might find this project interesting or least funny. It's based to two Fi IB318 drivers in 7.3 m3 sealed concrete enclosure, it's about ten times elements vas so I call it IB. Here's few shot during project.

























Now I have tested it and it seem to work as expected. Next I will build theater room over my subwoofer enclosure.

Here's my sort of build thread with more info and pictures.

[j.michael droke]

Hi there: Fabulous project! Hope you provide more details as the construction moves along. What is the black square surounding the driver (shown in the top side photo)? Are the drivers resting on rubber pads and then supported by the channel clips? I suppose the large boxout in the floor is for access to the drivers in the enclosure(?), what type of cover will be used in this opening? Will any lining be used in the enclosure? Is the enclosure moisture proofed for protection of the drivers? What crossover frequency will be used for the subs? ...regards, Michael

[Dave Holloway]

Now that is what you call a concrete speaker. I will have to have a word with my landlord.
Great stuff. cheers Dave.

[Pano]

Fantastic stuff. And Wow! what a lot of work.

BTW, thanks for your Genelec photo in the other thread. Interesting wall treatment.

[m R g S r]

wow thats dedication to building a theater room! nuts!

are they strictly true sub woofers (40hz and lower?) where you don't care about direction? aka where will these be firing in relation to the listener/viewer

[454Casull]

Where the hell is your dust mask?

[epa]

CHEERS
i like your dedication.
i wish i had room to do this.

[Ile]

Originally Posted by j.michael droke

What is the black square surounding the driver (shown in the top side photo)?

Element embeddings are coated using polyester resin to prevent crumbling particles from concrete embeddings to go jumping over elements. I dyed second layer black just to test how it will work and embedding might look bit better when element grilles are removed.

Polyester also prevent moisture coming to heated theater from cold cellar. Other areas of that concrete floor will be insulated.

Originally Posted by j.michael droke

Are the drivers resting on rubber pads and then supported by the channel clips?

Those elements have c-profil shaped rubber surrounding ring for sealing.



So I pressed elements to concrete empeddings "as is" using diy clamps.

Originally Posted by j.michael droke

I suppose the large boxout in the floor is for access to the drivers in the enclosure (?), what type of cover will be used in this opening?

Yes it will be cellar hatch to access elements, beer and potatos.

It already have weather strip sealed inner door made of film coated 3/4" plywood. There will be other one at floating floor level.

Originally Posted by j.michael droke

Will any lining be used in the enclosure? Is the enclosure moisture proofed for protection of the drivers? What crossover frequency will be used for the subs? ...regards, Michael

In theory it shouldn't need any lining inside, since it will be crossed at 80Hz (4.3m wave lenght) and modes shouldn't fit inside enclosure to cause problems. I'm not sure yet if this is true in practice. Have to make some measurements.

Cellar is pretty dry even it's been raining very much lately. Sure it have higher moisture than heated room, but surfaces are dry. It also have air ducts for venting. Elements are sort of moisture protected because those are made for car use, so I'm not very concerned about this.

[digits]

And to think some people live in houses made from sticks and leaves.

[Ile]

Originally Posted by Pano

Fantastic stuff. And Wow! what a lot of work.

Thanks from kind words.

Originally Posted by Pano

BTW, thanks for your Genelec photo in the other thread. Interesting wall treatment.

This study covers their main auditory acoustical treatments.

Here's all their academic papers.