So what determines if a sub can be sealed/ported?

[PV Audio 5,000+ posts]

actually its the ebp

True, but...

Low Qts subs, high bl. Don't do it ported only (.1-.3)
Mid qts subs, mid bl, Sure ported or sealed (.3-.5)

High qts subs, definite sealed (.5-1.0++)

General rule of thumb...works well //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

This is the rule I always go by, and it always seems to work.Curiously though, you also need to look at the Fs as well, as it can lend a hint to what it wants to do as well. Look at the Ascendant Av18. Fs is ~15-18hz IIRC. I doubt she wants to be sealed //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[SeanDub 10+ year member]

So Fi SSD 15s would be better sealed?

Fs = 25.9

Qts = 0.57

 

[NDMstang65 10+ year member]

True, but...
This is the rule I always go by, and it always seems to work.Curiously though, you also need to look at the Fs as well, as it can lend a hint to what it wants to do as well. Look at the Ascendant Av18. Fs is ~15-18hz IIRC. I doubt she wants to be sealed //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

What's more important, Fs or Vas? //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[NDMstang65 10+ year member]

So Fi SSD 15s would be better sealed?Fs = 25.9

Qts = 0.57

It works OK in 2 cubes sealed.

We recommend ported enclosures though.

 

[SeanDub 10+ year member]

It works OK in 2 cubes sealed.
We recommend ported enclosures though.

But if it had to be sealed, 2 cubes net would be as optimal as it gets?

 

[528hz 10+ year member]

SO......which parts of the sub affects this?

 

[NDMstang65 10+ year member]

But if it had to be sealed, 2 cubes net would be as optimal as it gets?

If you are referring 'net' as to volume after all displacements yes....from testing and listening I like that box the best, even though we really do not recommend it because it can tend to cause a 'saddle shape' in the response curve...

 

[528hz 10+ year member]

 

[SeanDub 10+ year member]

If you are referring 'net' as to volume after all displacements yes....from testing and listening I like that box the best, even though we really do not recommend it because it can tend to cause a 'saddle shape' in the response curve...

Ah, where are the peaks and what range is the valley?

 

[NDMstang65 10+ year member]

Peaks are right at 40Hz and 60Hz, the valley is roughly from 41-59...granted its only ~3dB or so but it's a weird little response curve that i really don't like...it sounds ok, but the ported enclosure sounds much better.

 

[Nosferatu333 10+ year member]

Great stuff fellaz,

now the question becomes how do we determine the ideal size of the enclosure? ie. cubes needed.

 

[audioarsonal 10+ year member]

I usually go with ported on anything over 65 EBP. EBP stands for Efficiency Bandwidth Product if no one has said this yet.

 

[audioarsonal 10+ year member]

EBP = Fs/Qes //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif
So your idq 10 will be 25.528/0.470 = 54, So a sealed box is optimal for the idq 10's

General rule is closer to 50 sealed and closer to 100 ported

45 and under I would do sealed.45-65 either.And 65 and up ported.

So it could go either way with that sub.