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Help building box for 2 Polk MM1040

4K views 2 replies 2 participants last post by  amkarlix 
#1 ·
I would like a little bit of help from the people here that are more experienced than myself. I built a box for 2 Polk MM1040 subs a month or so ago. I followed the recommendations on Polks website for the box dimensions, but am not happy with the results. I think the box is too small. I plugged the dimensions into the box calc on the RE website, and the volume turns out to be slightly less than what Polk recommends, not even accounting for displacement. The subs sound really good on some songs, but seem to lack range and have kind of a boomy sound. I was wondering if someone here had experience with these subs in ported enclosures, or could tell me what size enclosure might be more appropriate for the subs. Thanks in advance for any help.

Aaron
 
#2 ·
What is your amp?

Does it have a subsonic filter? It might be too high. The low pass filter might also be too low.

Have you tried test tones? 20-100Hz should be perfect for finding the peak frequency of the box.

If you have an ipod touch or iphone, get "tone; the ultimate tone generator" or "audiotest" or "oscillator lite" or "tono"

OR just make the tones yourself in audacity or google search for test tones

The sub itself is only 10", and 350w rms. That's hardly going to shake the car even at peak box placement.

If the box is too small, try inverting the subwoofer(s) or adding polyfil or both!

by inverting the subs, you get more volume inside since the sub is not taking up that room anymore.

How hard do the subs actually hit?

why don't you build a box that is exactly to spec that the subs require (width, length, etc) and judge for yourself if those are even capable of what you expect them to do.

Also might be the way you have them wired.

Are they both on 350w rms @ 4 ohms from a dual channel amp that does at least 350w rms per channel?

Or in parallel presenting a 2 ohm load to the amp that has 700w rms @ 2 ohms?

Lots of things to think about here.

Pictures would be nice too.
 
#3 ·
The box that they are in is built exactly to the specs that polk recommends for them. They are powered by a cadence zrs7000d wired at 2 ohm, which provides more than enough power. I will check the settings on the amp, and adjust the subsonic filter and see if that makes any difference. I'm not complaining about the output of the subs, just how they sound with a lot of music.
 
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