Hi. I am building a box for 4 of the MJ-18's. They will be used for home theater and music. So I think im going with 4.5 cubic feet each and tuned to 30hz. Should each subwoofer have its own chamber or should they all be together. If they are together how many ports should I use and what dimensions should they be.

Thanks alot!

Hi Keith,

The 4.5 cube box size is a good recommendation for music, however, if you plan to use them for home theatre as well, many folks suggest building a bigger box and tuning lower to take advantage of the near-subsonic content in movies.

Its all dependent on what you can accommodate in you room of course. You can use one MJ-18 in an 8.8 cube box tuned to 18Hz to catch those lows for HT and still be fine for music. The sub will of course, not be as efficient when playing music as you are not able to take advantage of the port output (due to the extremely low tuning).

On the flip side, if you are strapped for space and can only do the 4.5 cubes per driver, you can always compensate by using an EQ or some other boost when watching movies.

I'd suggest you consider how you plan to use them most of the time and work towards that.

Best,

Mark

Thanks for the response mark.

They will primarily be used for music and My space is limited. So i am going to build 2 boxes. 2 woofers per box. 9 cubic feet. My ports are going to be 4x18 and 16.5 inches long.

does this sound right to you?

thanks

Yup. Sounds about right. Remember, if you used WinISD to calculate the port tuning, the program already includes the port volume in its calculations. IOW, don't add the port volume to your 4.5 cubes - you will end up with a lower tuning then.

Best,

Mark

OK thanks alot Mark.

I allready had these speakers in some huge boxes tuned real low and they sounded really good but they took up alot of space

thank you

Build two separate cabinets and run them in stereo

That would be fun...would require some pretty stout monitors for everything above 40Hz, though...