i want to build a sub for my home theater

[michelevit]

i am finishing my basement theater. i currently am using a
logitech surround sound computer system and its ok, but now
i want to start building my speakers. the logitech was just a temporary system and now its time to upgrade.

i have some good woodworking tools and want to begin with
the sub.

the room is very small 12 x 12 feet with low 6 foot ceilings.

i've perused the forums and the net, but i havent found
any good plans yet. i'd like to build something that is great for movies and ok for music.

i've seen the partsexpress kits, but i'd like the satisfaction
of building the cabinets myself.


any leads would be greatly appreciated.

thanks in advance.

mv.

[454Casull]

6x12x12? Be prepared to make/buy some bass traps - you most likely have some severe bass modes.

[VT67]

Have a look at this.
http://www.hardwareanalysis.com/content/article/1789/

Regards

[BassAwdyO]

6x12x12? Be prepared to make/buy some bass traps - you most likely have some severe bass modes.

Or go with dipoles and cross to sealed subs for the low bass

[michelevit]

Or go with dipoles and cross to sealed subs for the low bass-

I am not sure what that means. I spent some time at
the lumber yard and am ready to start this weekend.

Any other ideas?

[JinMTVT]

just buy as many 18" as u can afford
make 2 ported boxes and slap em all on

buy a good low distortion amplifier ..

get enough oumphh..

[BassAwdyO]

Or go with dipoles and cross to sealed subs for the low bass-

Dipoles are Boxless speakers where the front and rear of the driver both radiate. They create a figure 8 polar response pattern and interact much less with the room(minimizing the effect of room modes). They will give a much more even dispersion throughout the room and almost certianly have better sound quality.

Then you can cross over the dipoles to sealed or Bass reflex boxes at the frequency which a half wavelength equals the longest room dimension(where no modes exist), and you will have the full range of bass with minimal room interaction.

The reason for crossing the dipoles is because they have poor low bass performance due to the front wave and rear wave canceling eachother at low frequencys. A sealed or ported enclosure will have much better performance at those low frequencys.

If you dont go with dipoles and cross them low then You'll probably want to put your subs very close to the listening position to avoid the bass modes. Otherwise things might get very funny

[dangus]

The Adire Tempest isn't the bargain it used to be, but it's still a worthy driver. See the plans at Adire's web site. One or two (if you're criminally insane) of those, driven by a Behringer EP2500 power amp (amazingly cheap), should be adequate.

[Timn8ter]

I like the Tempest but one (or two ) of the 15" in a 12 x 12 room would be a bit much IMHO. One of the smaller drivers like a 10" or 12" probably will do the job. If the dimensions you provided are accurate you're going to have a 47Hz mode right in the middle of the room. Try to avoid placing speakers and seats on any 3 foot distances.

[paulspencer]

6 ft ceiling? That can't be right! That is less than the height of a regular door! I'd be touching the ceiling with my head when walking in!

The room might be a bit small to fit in some dipoles, but then again he could make some and put them in the corners. Yes dipoles can be made in corners.

First thing that comes to mind though it either a compact sealed sub or just make some mains which have some decent bass.

In fact you could easily make mains 3 way and use some 10" woofers from 80 Hz down and a 6.5" midbass in a sealed box. Just put a 2nd order lowpass on the woofers and put them in a sealed box (side firing to make em slim).

This will probably work better than subs in this case. The woofers would be bi-amped with a simple active filter on them and their own amp.