box question (frequency change mostly)

[k_schutte 10+ year member]

Well, I have a really nice box I built a while back for my RE XXX15 and got rid of it about a motnh later and have had the box sitting here since. It is 4ft^3 tuned to 33hz.

I now have a pair of MTX 8500 10"s and was thinking about making a new front baffle for those. Of course, they only need like 1.5ft^3 per sub so the box is a little big. My plan is to just add some decent sized corner pieces to bring the volume down a decent amount but I was wondering how that would change the tuning frequency of the box? I am hoping to get the tuning closer to 38hz or so anyways so If removing box volume would in turn raise the tuning frequency I think I might give that a try.

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[westman995 10+ year member]

The frequency i think goes up when you make the box smaller, but keep the same port.. Thats the way i see it.

 

[k_schutte 10+ year member]

Yup... I figured it out yesterday pretty easily by just using a box calculator and then just subtracting some area... Looks like if I can remove close .75ft^3 I will be around the 36hz~ I am looking for.

subs are .15 each so all I need to get rid of is roughly .45... some corner pieces, bracing and a PVC pipe on the port end should do the trick easily enough...

 

[westman995 10+ year member]

Ya thats the same way i figured it out. I was considering getting rid of a little space in the box i just built too by adding some braces and/or corner pieces, but that would raise the tuning and its already at 37 so im just going to leave it as-is, dont want to take it apart since its already glued together and all that.

 

[k_schutte 10+ year member]

yeah, mine is at like 32hz right now and should be closer to 37 after removing about .75-1 ft^3 of air space...

The box use to house my RE XXX15, now it will hold a pair of MTX 8500 10"s

 

[westman995 10+ year member]

Should work out pretty good. Should also be a good frequency for the subs too i would think.

Hmm, just realized something.. You wanted to sell the 8500's right? I dono if the guy would be interested or not, but this guy that is like 20 mins away from me hes on another forum and he had one 12 8500 i think, and he messed up the dust cap really bad. I wonder if he'd be interested in these if you still want to sell.

 

[k_schutte 10+ year member]

I'd sell them... just don' tplan on anyone buying them so I figured I would toss them in my car in a week or so if I stil have them...