Ported vs. Sealed sub enclosures

[Amoeba]

I was reading through a recent thread and a question came up about sealed vs. ported enclosures. 1sty replied "ported" but with no explanation or reasoning. Now, I'll take his word for it (he *is* one of the gurus after all) but the question is why exactly?

First off, what is a "sealed" enclosure? Ported I would think would be an enclosure where there's a tube/hole which allows air to flow in and out of the inside of the enclosure moving with the throw of the speaker. Is this correct?

What are the advantages/disadvantages of Sealed sub enclosures?

What are the advantages/disadvantages of Ported sub enclosures?

In what circumstances would a sealed enclosure be a better choice than a ported enclosure or vice versa? (Like say, if the SQ or SPL depended on speaker size or something... I dunno, hence the question).

Let the debate begin!

 

[vindication]

Ported without a doubt!

 

[II-Savy]

The ported enclosures have a "blowy" deep, almost a bit slower reactive sound. IE the real deep long bass is usually unreal in a ported enclosure.

The sealed to me is a faster, harder hitting, compact tight sound. Not as blowy and "deep" sounding.

This backs up what I am saying -

"Sealed enclosure - air tight enclosure that completely isolates the back wave of the driver from the front. Very tight, defined sound (with Qtc = 0.707) with very good transient response and power handling. Low frequency roll-off is at -12 dB/octave. Less efficient than other designs, and higher distortion levels at resonance. Easy to design and build. Originally this design was pioneered and marketed by companies like Acoustic Research. See Qtc."

Ported Enclosure - a type of speaker enclosure that uses a duct or port to improve efficiency at low frequencies. Excellent design for lower power systems, as the port often adds up to +3 dB to low frequency efficiency. F3 can be set considerably lower with proper design, although low frequency roll-off is generally -24 dB/octave. Good transient response with proper tuning, although the driver loses damping below the tuning frequency. Excellent power handling about Fb, but source material or frequencies below Fb cause the driver to progressively perform as if it were not enclosed at all. Due to this, ported enclosures without a low frequency filter may have lower power handling compared to other designs. More difficult to properly build and tune than a sealed enclosure, with several "optimum" alignments available depending upon the Qts of the driver. I highly recommend Vance Dickason's "The Loudspeaker Design Cookbook," which goes into great detail concerning the different possible alignments of ported enclosures. The best way to model these alignments is with a software program, where changes in tuning and enclosure size can be immediately noted. Though it can be dated to the 1930's, the ported alignments were thoroughly researched and standardized by A.N. Thiele in the 60's and R. Small in the 70's. This work was further expanded by D.B. Keele and others.

 

[AODfan]

From what I know, Sealed is more for SQ, where as Ported is for SPL, pretty much its up to what you want to hear.

 

[got wake?]

http://www.diysubwoofers.org/


read up. i prefer ported, tuned below 35 hz.

 

[BeNegative]

it's a matter of what type of sound u want

 

[Poseur]

There is no particular charecteristic you can attribute to ported. it's all matter of tuning. there's many ways to port a box. however we're talkinga bout making a ported box, not buying a cheezy prefab. prefabs are notoriously hirrible cause they're tunes way high and generally not large enough. The disadvanatage of ported is the size and complexity of tuning your box right. Sealed is easy, and sounds fairly good without much work nto to mention takes up about half the space, however ported is much more efficient