now it's too small and tuned too high. (who would have thought... haha) It was my first sub box. It's time for a new box.

A bit of Background
My setup is cheap...
sub - Boss SE122DVC - 450w RMS
Amp - Jensen power 900 - 340W RMS

a picture of the box I built (21"w X 15"h x 13"d)

I just checked, and the box is only 1.75 cubes after port reductions and owners manual calls for 2 cubes. (driver included)

Owners manual recommends a res. freq. of 36 Hz, but using the peak current method, it is actually tuned to a high ~47Hz.

Because I was(am) a noob, instead of using one port the recommended size(4" x 6" long), I used 2 (2.5" x 4") thinking that it was close enough, was I ever wrong...

Down to Business
The sub makes a sound (rattle?) when the amp is right at or before clipping that doesn't sound like distortion to me. It only happens on certain beats, and the amp can be driven right into clipping on some songs without making the sound. The sound can also be stopped by sealing the box by covering the ports with my hands, but it is not air noise. I am guessing this is due to the high tune?



Rather then messing around, I am just going to build a new box.(ported) But this time I am going to put a little bit of thought into it to try to get the most out of my sub. I have a couple questions.

Could the sub be damaged because of whatever it is that is causing the rattle? (it has been ran like this for ~3 months)

Will the sub actually be noticeably louder/sound better with a 2 cube box closer to 36Hz?

Owners manual recommends a port diameter of 4" and a length of 6". If I wanted to make a rectangular port down the one side of the box, what would be the best size/way? or would it be better to buy a round port? Can plastic pipe be used as an effective port?

What program(s) do you recommend for designing a box?

 

"the sound" you might be talking about could what i have, i tuned my box high so it got loud on SOME songs, but there are other i just cannont listen to... i like the loud but i cant listen to anything but rap and stuff like that or it just sounds like death. At low volumes does the sub make any other noise but bass?

 

I don't think it makes the noise at low volume. I will check tomorrow when I am outside of town. What is your box tuned to?


I'll also try to take a vid tomorrow.

 

4.2cuft @ 44hz.

 

Try using the RE Audio Enclosure Calculator. It lets you plug in different dimensions and such. You can adjust the length of the port and cubic footage.

 

Well... If it sounds like a rattle, it probably is....

pulled the sub out of my truck and the rattle stopped. The reason putting my hands over the ports stopped it is because it reduced the volume just enough.

I never claimed to be smart... haha
Thanks. I will look into it tonight and let you guys know what I come up with.

 

Ya lets us know. And post some pictures of the new enclosure

 

so I have a design that will work from the RE calc, but it has twice the port area of the recommended box. Is that a big deal?