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View Full Version : Should "sound quality" builds ever use ported boxes?



mugen08
07-09-2013, 12:51 PM
Yeah I don't really have much experience with enclosure design, but my basic understanding is that a ported box will be 50-100% louder at the tuning frequency than a sealed box, but basically the bass isn't as accurate as a sealed box.

I guess my question is how much of audible difference is there between a good ported box and a sealed box in terms of accurate bass reproduction both at tuning frequency and way outside of it?

Would a ported box (even a good one) mask the attributes of a good sound quality sub?

RangerDangerV2
07-09-2013, 12:53 PM
all in the design really... I have found that bass reflex has a better transient response most of the time over a sealed enclosure. many will say that is false, but it is what I have found to be true.

mugen08
07-09-2013, 12:58 PM
Also what Q factor ranges are suitable for sealed vs ported?

NoLoud4U
07-09-2013, 01:07 PM
Scott Bulwalda had the highest SQ ever score with a bandpass.

loudlittlefvkus
07-09-2013, 11:51 PM
I've had my kicker cvx's in a sealed box(which im pretty sure were too big, 6 cuft.), and in a ported box i made on sketchup, and i think the ported box sounds a hell of a lot better. again, i think it might have been because the boxes were too big, because they sounded kind of muddy.. but i dont hear a huge difference in volume when it goes from lows to highs, (tuned at 34), it all sounds pretty natural. it all really depends on how you build it, and if its designed right. dont sealed boxes have a resonant frequency too, where itll sound a little louder at that frequency?

Danometal
07-10-2013, 12:11 AM
Sealed = SQ / Ported = SPL is an unfortunate misconception, just like the misconception that larger speakers are "slower" than smaller speakers.

My system is straight SQ oriented, and I went ported (tuned very low to 25 hz) for flat frequency response.

Garbage pre-fab ported boxes are largely responsible for the anti-SQ reputation, as most of them are way too small and tuned way too high. So, by comparison, yes, any sealed box will mop the floor with a pre-fab ported box for SQ. Most pre-fabs fart like box fans at any kind of reasonably low frequency.

loudlittlefvkus
07-10-2013, 12:17 AM
^^yup. if you can properly design and build a ported box, or pay someone who knows what theyre doing to make you one, youll get great sound quality

DUBSLIFE5150
07-10-2013, 12:26 AM
this may help
http://www.caraudio.com/forums/enclosure-design-construction-help/68635-sealed-vs-ported-basic-info.html

Danometal
07-10-2013, 12:32 AM
Oh, and to further add; sealed boxes REQUIRE cabin gain to somewhat balance out the typical early roll-off of the frequency response as the frequency gets lower.

In a 4 door sedan like mine, rolling every window down and opening the sun roof removes quite a bit of the cabin gain, and that also introduces a ton of wind noise at the same time. Overcoming all that is a tall order to ask of a sealed sub.

Both problems are solved with a good ported box; 1). Doesn't need cabin gain to get low 2). More output period, good to have with extra noise going on.

T3mpest
07-10-2013, 05:59 PM
Yeah I don't really have much experience with enclosure design, but my basic understanding is that a ported box will be 50-100% louder at the tuning frequency than a sealed box, but basically the bass isn't as accurate as a sealed box.

I guess my question is how much of audible difference is there between a good ported box and a sealed box in terms of accurate bass reproduction both at tuning frequency and way outside of it?

Would a ported box (even a good one) mask the attributes of a good sound quality sub?

Subwoofer SQ is almost exclusively about frequency response. Anyone that says different is wrong, that's the honest truth. Generally in a car for sq your looking for a fairly flat response from the midbass to subbass, generally down to 40hz or so. From 40 and down you actually want a rising spl, around around 6-12db/octave. Not super exact, but those curves generally sound the flattest to the ear and won't be missing anything. Despite what many think, you do NOT want RTA flat for SQ, even in competition. Outside competition, the curve I described still sounds VERY good, but most people will bump the whole subbass region up, so the flat transition from midbass to subbass might have a bump, how much depends on what you listen to. The curve i described is basically what the sub itself should be doing between 80 and 20hz, how much louder you want all that vs the rest of the music is up to you.

Anyway sealed boxes tend to produce good frequency response in most cars without a lot of guess work. Is it perfect, no, no setup is, but it'll get you in the ballpark as long as your box is appropriately sized for the vehicles cabin gain and you used a good sub for a sealed enclosure.

Now if you have equalization, ported becomes a better choice all around. Ported has some inherent SQ advantages. Since the sub moves less during tuning and is more effecient overall, distortion is reduced. A ported sub playing anywhere near tuning has less distortion than a sealed sub playing the same note. The issue is again, the frequency response, which is the most important thing and what tends to make many ported boxes not sound as good. Anyway, if you have an EQ you can simply reduce the frequencies that your ported box is playing too loudly, then your getting great effeciency since your ported, lowered distortion AND good frequency response.

Lastly, some subs work better in some boxes than others. A high fs high q sub isn't going to have good sq in a sealed box in a large car, it's going to lack too much low end. Even with EQ, you may have mechanical or thermal limits to take into account. That sub, may however, do very well in a large car if it's in a large box tuned low.. A higher q lower fs sub would be the opposite, it'll be fairly flat in a sealed box, but in a ported box would be very loud and boomy wherever you tune it. For example, my last subs were very low q AND low FS. Somewhat unusual pairing, but they EXCELLED in a small ported box. 3-3.5cubes tuned to about 25-30hz has great frequency response in most cars. Better than a sealed box would have been in most cases and certainly more accurate than a larger ported box, unless it's a suv, then you'd want to go a bit bigger.

So it's not really all in the box as some say.. Really, it's all in the box that the combination that sub and vehicle dicatate works best. If you only have 5 cubes to play with a sub that will need a ported box of at least 6 cubes to play flat, isn't a SQ sub for that vehicle.

Danometal
07-10-2013, 06:21 PM
I'm glad to see someone else has accepted the not-so-secret secret of SQ ported boxes; tuning low. Your average installer at an average stereo shop will generally recommend tuning in the mid 30s for lots of output.

The bad news with that is you get a harsh peak around 40-60 hz, a low end response that falls off a cliff (some people think 35 hz is low), and the inescapable group delay will be on the low end of the audible specrum vs. well below it.

Tuning low solves each of those problems.

So, in the end, tuning low nets you a response curve that stands above the rest, and you also get superior output compared to its sealed counterpart. This is woofer dependant though. Some subs only respond properly sealed..

bubbagumper6
07-10-2013, 06:45 PM
I'd say it's more of a question of tuning. SPL guys will tend to tune higher for peak numbers while tuning lower produces a more broad response (i.e. 'getting lower') and would be more SQ oriented.