Sealed vs Ported Subwoofers

What Shadorne said. Ported subs are usually (though not always) less damped than sealed subs. That helps for high output capability at very low frequencies (read "HT"), but might cause some issues when optimizing for a music system. However, as the other posts note, individual subwoofer designs vary, as do main speaker designs. The trick re: damping is to find a sub and mains that are similarly damped at the crossover point. I'd guess that, more often than not, a sealed sub will be a better choice, but "more often than not" is not the same thing as always.

Good Luck

Marty

I agree, in general, with Shadorne -and- Gmuffley. Box size is another factor to consider. Using the same size box, you will get deeper extension and higher output with a ported design. The sealed box will give you a flatter and more gradual roll off. Recent sealed subwoofer designs use smaller boxes with very powerful amplifiers with compensation to achieve better output and extension. Some have been very popular. My old ported 12" Mirage(Energy) would shake the walls in a way my sealed 10" Parts Express Titanic subs will not. Ultimately, the sealed subs work better in my room.

Subwoofers are very commonly used with electronic equalization. The inherently-smooth slow rolloff of a sealed system is best suited to equalization, and the equalization can take care of the fact that the rolloff begins at a higher frequency.

There is no better..... but You can certainly prefer one over the other and there are implications of one being better over an extended period of time.
If a ported driver is ported correctly, it will be acoustically flat. If a sealed driver is in the correct encloser and you achieve a final QTS @ .707, you have an acoustically flat sealed driver. The big difference is that it is typically easier to find a driver that will achieve a very low frequency from a ported design and when the driver is at its minimum frequency a ported sub will then roll off @ 24 db per octave, so below its rolloff there is very little output. In a sealed design, once a driver hits its low frequency rolloff, it rolls @ 6db per octave, so you will still have very useable low end frequency below the point where it begins to roll. Because of this, the two do sound a little different from one to the other. Also, I had said that over time the implications are that one is better. That is because as a driver wears, its specs change, especially its qms... as the specs change a ported design has a tougher time maintaining its accuracy, where a sealed woofer will stay fairly true... Of course, that does take a fair amount of wear. As alluded to above by another... Any woofer in its perfect sealed box, will always need a larger encloser for its perfect ported box, But there are very few woofers (very few, not zero) that truly are versitile enough to use ported or sealed. I hope this helps, Tim

Timlub,

Very well said. Your reply zeroes in to the fact that cost is a major factor in loudspeaker design. While Wilson uses a ported design in it's flagship speaker it delivers sound that would take a much larger design, requiring a much larger room. If you have no constraints on the size of you room or budget you can always improve on commercially designed speakers.

Ported designs are a natural compromise that is utilized in many designs because of efficiency, both in size and cost.

Designing and building a loudspeaker that prevents the front wave and back wave of a driver from meeting is easy. Choosing drivers that crave that alignment is expensive. Doing it so that it sounds better than anything else is priceless! I couldn't resist saying that!!!

Ken