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Old 29th December 2002, 03:34 AM   #1
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Question porting a sealed sub, yes or no

I have a 12" sealed box 200 watt sub in a 1 cubic foot wood box, and I was thinking about porting it. Would there be a big difference , and, how should i go about calculating the size and length of the port? Thanks!!
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Old 29th December 2002, 04:17 AM   #2
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We'll need to know what the specs for the driver are. You'll also probably need to make the box bigger.
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Old 29th December 2002, 04:28 AM   #3
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There is archaeological evidence that ancient cultures performed a primitive form of surgery involving the cutting of coarse holes in the skull.

We are not sure exactly why, perhaps the individuals suffered from some aliment involving the head, or perhaps they thought there was some evil demon within the skull that needed to be allowed to escape. We do know that many of these operations were fatal since some of the found skulls showed no sign of healing, although others apparently survived a long time afterwards.

It seems to me that these ancient operators might have been using the same diagnostic approach.

There is a very tiny chance that this will cause some benefit.
There is a huge chance that you will want to bury your experiment afterwards. Vented drivers and sealed box drivers are often quite different. We would have no idea without exact specs.

The likelihood is, your subwoofer needs to be ported about as much as you would need a hole in your head.
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Old 29th December 2002, 04:53 AM   #4
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i think ill stick with it like it is, it doesn't sound very promising anymore. But thanks for the advice and the stories........
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Old 29th December 2002, 03:30 PM   #5
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I don't know if you know about Qtc, etc.

Subs can have Qtc's between .5 and 1.

If your sub has a Qtc much over .5, the answer is no, don't port.
If your sub has a Qtc around .5, the answer is yes, you can port.

I wouldn't go porting the sub unless I knew this info.

If you have some measuring equipment like a good microphone and a multimeter, you can perform tests using an online freeware tone generator.

If you don't want to get into that, do you have some frequency response charts and impedance charts you could scan and post? Sometimes they are incuded with the sub. We could tell from that.

Failing that, what is your sub? There might be info on the net.

It is not as crazy an idea as you might think. In the past, several models have been manufactured that had a plug for the port so the owner could switch from ported to sealed style.

One of our members here built his sub with a screw on cap for the port. He likes it sealed for music, ported for home theater. So it can be done. The individual sub just has to be built right.

Here is the thread where he designed the sub. He said in a later thread that he was happy with the results.
Calculating room gain

So it can be done,
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