Fear of going ported. - AVS Forum
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post #1 of 9 Old 01-09-2013, 10:36 AM - Thread Starter
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The past few weeks I've been working on designs for a dual 12" sub enclosure. Using Winisd Pro I came up with a good design that would allow for my 12" subs to reach about -3db at around 16Hz. With an fs=29.1 Hz, I designed the box to be ported and tuned for around 18Hz. (without ports it was around -3db at 28Hz)

My design called for around 6ft^3 internall for each sub, with a single port with 4" D and 10" L. Basically a massive 4'x2'x2' box with a divider in the middle.

Now, this past weekend I built the box without adding the ports as they haven't arrived yet. But, after testing the subs with a few songs it sounded amazing. It hit very deep with plenty of output. It played notes my Bic F12 was oblivious to.

I'm at a point right now that I'm afraid to add the ports for fear of ruining this quality sound, so I am here for advice. Are my fears unfounded? Can I trust my winisd design or is there something that can possibly be miscalculated?

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post #2 of 9 Old 01-09-2013, 10:57 AM
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Quote:
Originally Posted by Louquid View Post

The past few weeks I've been working on designs for a dual 12" sub enclosure. Using Winisd Pro I came up with a good design that would allow for my 12" subs to reach about -3db at around 16Hz. With an fs=29.1 Hz, I designed the box to be ported and tuned for around 18Hz. (without ports it was around -3db at 28Hz)
My design called for around 6ft^3 internall for each sub, with a single port with 4" D and 10" L. Basically a massive 4'x2'x2' box with a divider in the middle.
Now, this past weekend I built the box without adding the ports as they haven't arrived yet. But, after testing the subs with a few songs it sounded amazing. It hit very deep with plenty of output. It played notes my Bic F12 was oblivious to.
I'm at a point right now that I'm afraid to add the ports for fear of ruining this quality sound, so I am here for advice. Are my fears unfounded? Can I trust my winisd design or is there something that can possibly be miscalculated?

That is a big cabinet for sealed. It seems like with the size of the cabinet you would benefit from going ported, that said, your port seems pretty small for a an 18hz tune...
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post #3 of 9 Old 01-09-2013, 11:00 AM - Thread Starter
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Originally Posted by ack_bk View Post

That is a big cabinet for sealed. It seems like with the size of the cabinet you would benefit from going ported, that said, your port seems pretty small for a an 18hz tune...

Yes, the box was built this large with full intentions of going ported. What problems would arise with a port that's too small? Would it simply not be tuned for 18Hz, or would it create noise and chuffing?

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post #4 of 9 Old 01-09-2013, 11:07 AM
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Originally Posted by Louquid View Post

Yes, the box was built this large with full intentions of going ported. What problems would arise with a port that's too small? Would it simply not be tuned for 18Hz, or would it create noise and chuffing?

Yes, you would have port noise and chuffing. And perhaps if the ports were grossly undersized it would move towards sealed behavior?

Generally a low tune with adequate port velocity is going to require some pretty long ports.
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post #5 of 9 Old 01-09-2013, 11:12 AM
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Thats about the right port length, though I show it being closer to a 21hz tune.

There would be a single 4" port per 6ft^3 enclsoure right? Not sure what driver you have but tht should give plenty of airflow for a 12" sub. If you dont like how the ported enclosure sounds you could always plug up the port.
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post #6 of 9 Old 01-09-2013, 12:03 PM - Thread Starter
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Thanks guys. If my tuning is a bit higher then I'm perfectly fine with that. I just don't want it to be a complete disaster. But I'll give it a shot and see what happens. I'll try some more recalculating and see what happens with different port scenarios. Thanks!

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post #7 of 9 Old 01-09-2013, 12:56 PM
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What drivers are they? Sounds like they have a high Qts which is why they're working so well in the large sealed boxes, and require large ported boxes.

Like mtg said, you could always plug the ports.
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post #8 of 9 Old 01-09-2013, 01:14 PM - Thread Starter
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Pioneer TS-w303r. They do have a high Q of .65 Qts.

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post #9 of 9 Old 01-09-2013, 05:33 PM
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Be extremely careful of how much power you apply to that driver, listed xmax is only 5.9 mm... I dont see an xlim listed, hopefully it's substantially higher.
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