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well i didnt mean for a specific sub but one with the internal volume thats right. there are alot of sub boxes that have the right volume for a sealed box and sound great

Fishy wrote:I think it has a lot to do with the sub as well. I tried my 10w3's sealed .75 ft^3(JL recommends .625) and didn't like the upper bass "ring" they seemed to have. Even tried polyfill to no avail. Maybe I'm just used to the higher output of my ported box. Its tuned to 28 Hz and has a lot better low end extension and seems to blend better with my front stage. Then again it may be I turned the gains up a bit more with the sealed to compensate for the lack of bass in the 40-50 Hz range.

-Fishy

same exact story with quite a few lower/midrange xmax woofs... its just too hard to get good extension while maintaining a decent amount of output.

I think it has a lot to do with the sub as well. I tried my 10w3's sealed .75 ft^3(JL recommends .625) and didn't like the upper bass "ring" they seemed to have. Even tried polyfill to no avail. Maybe I'm just used to the higher output of my ported box. Its tuned to 28 Hz and has a lot better low end extension and seems to blend better with my front stage. Then again it may be I turned the gains up a bit more with the sealed to compensate for the lack of bass in the 40-50 Hz range.

-Fishy

yea, but a prefab box for a specific sub isn't really a "prefab".

That being said... nothing holds a candle to a custom box... and those subzone boxes arent cheap.

there is nothing wrong with a prefab box if its built good like a subzone box and made to the specs of the sub. and they save you alot of time. and i love sealed boxes but thats my opinion and taste its alot easier to get great sq out of the sub and they still get plenty loud for most people like an elevation audio pro 12 will get louder than alot of people want and sound very good.

I would think group delay and such could be addressed by a smaller sized lower tuned ported box. Its difficult to have enough port area in a small box to make it useful... what you end up with is pretty much a transmission line.

Some subs also dont take very well to smaller sized boxes - but an "sq" woofer definitely should.

I can't really see flattening out impedence as mattering all that much, effeciancy at different frequencies will be different anyway.

Jonathan pretty much summed it up before I got back here.
you can get a fairly flat response from a ported box, but by the time you do that, you're adding phase shift and delay from all of the EQing, and you're not gaining any of the advantages of going ported to begin with, so you may as well go sealed at that point.
I like ported enclosures. I use them a lot. They just aren't the ideal solution for actual accuracy (transparent response) in a car setting. This raelly doesn't matter to 99% of people though, since most folks don't want a flat response anyway. They want to crank the bass, have crisp treble, and acceptable vocal ranges.
ported can offer lower distortion with higher group delay and slower transiet response, but how much most people will notice this is really up for debate.

"Why does transient response suffer in a ported box? Can this generalization be made across the board?"

The increased mechanical control of the enclosure, due to the port, is what makes the response suffer. The generalization can be made across the board for any ported box, but good designs minimize problems. The tuning and enclosure itself will take an effect on where this occurs at and how negatively it affects it. After the port becomes inactive (too slow to react to changes in woofer movement, aka higher frequencies) then the enclosure will perform nearly the same as a large sealed. Group delay (which corresponds to transient response) can be minimized and be below what is considered to be the threshold of human hearing (many consider that to be 20 milliseconds, others consider it 10ms), but of course that is a debatable issue and the answer is usually left as ported simply having worse transient response.

You can get a flat response ported via EQing, but it's more difficult in a car simply because of the cabin gain. In home audio, ported can have a flatter response than sealed because you don't have a lot of room gain, ported has a lower system fs than sealed when tuned to do so. In a car, sealed, AP and infinite baffle offer the flattest response you can get. Remember that EQing adds phase shifts and complicates the load presented to the amplifier since you are cutting and boosting. The best EQing is none at all, IMO the best systems offer a relatively flat response from the get-go, and only minor tweaks are needed to get it right. AP membranes also help flatten the impedance curve presented to an amplifier, ensuring a consistent load and a predictable frequency response. The purist audiophile isn't going to choose ported, for the same reason that they wouldn't use high order crossovers on speakers. They are focused on good phase alignment and transient response, as well as a flat, predictable frequency response without a lot of tuning and extras to get it. That is where sealed, AP, or infinite baffle excel at. Most people in the car audio hobby want a loud system that sounds good, which is why ported boxes and high order crossovers give good results. That's also why I recommend ported to those types of people, because of the fact that sealed and AP, while they offer the best SQ IMO, don't do as well at high volumes. If you choose a sealed box and have nothing but high volumes in mind, you're likely going to hear a lot of distortion due to the higher excursions. IMO it is much more noticeable than a difference in transient response. Most top end SQ equipment isn't really that loud (especially components) because the drivers are less efficient due to the damping of the drivers, materials chosen, suspension used, etc. Being more of a purist SQ guy and also because of space restrictions, I use sealed, but I've used ported before for certain applications and have gotten good results with both. It's all about matching the horse to the course, you have to know your goals.

I'm fairly certain you can get a flat response with a ported box?

Would probably just take more work and some EQ work.

Why does transient response suffer in a ported box? Can this generalization be made across the board?

You made valid points, but I don't think I'd say ported is good for SQ per se.. it will however, as you said, give more output with less power, and actually tuned low, the box will peak right where all that nice deep bass is, which is what most people really want anyway, even if they hate to admit it, or don't realize it.
As for actual SQ, while distortion may be lower with a vented enclosuure, for strictly "SQ" purposes, sealed will give a flat response, with less group delay and no port coloration. This is why ideally, AP enclosures work so well in a car for SQ. They give the flat response of a large sealed enclosure, but they improve mechanical power handling, filter high frequency information, and reduce 2nd and 3rd order harmonics.
Like everything though, there's always a drawback. In this case, an AP box eats power to reach acceptable volumes, which is what your ported enclosure will correct.

Without getting into more esoteric designs like bi-chambered aperiodic enclosures (ABC boxes) I agree ported is the easiest way to use the least amount of power and get good sound with good volume levels. Purely based on SQ though, the ported box does have some drawbacks, but honestly unless you're worried about an RTA curve, or you really know what a flat response sounds like and you're sure it's what you want, ported boxes usually give a person the best results in a car for overall balance between efficiency, SQ, etc. I suggest them to just about anybody who doesn't know exactly what he or she wants from teh start.