6 replies to this topic

[Shreknos]

hi guys.. i dont know if this has been asked before but i dont think it has... i was just on the DD website, and DD in all thier glory claim that a ported box is actually better for sq than a small sealed one... how much truth is behind this claim, and would a few different people in the know be so kind as to explain this phenomenon to the rest of us idiots (me)!!! i found it interesting because i dont believe that DD actually sell prefab boxes, so why would they make such a claim if subs actually did sound better in sealed boxes... also, im thinking of upgrading my type x to the 9112 with the m1 to match, if i make a big ported box, tuned to say 35hz, will this suit my type x and my 9112 until i upgrade??? is it bigger the better and louder, or will they both need a box to suit neach sub?? thanks for the help...

[~Spyne~]

it all depends on the sub.
dd subs suit ported boxes, so will provide better sq in a ported enclosure
other subs suit sealed boxes, so have better sq in sealed enclosures

[Caldor]

From the sound pros Ive listened too, a passive radaitor enclosure will eliminate the problems of port noise and the other issues with vented boxes.

A sealed box will have better transient response though, and if you ask me, the lower F3 from vented boxes may not be worth it for the downside they bring.

As Spyne has said differences in the Q of the driver and the free resonance will influence the box performance anyway

[fuddbutter]

sealed is easy to get right, build a box, slap in a sub and if it is close to the right size it will sound nice.
ported box's if there not 100% they will sound like crappy.
if done right they can sound awesome (look at nearlt every home audio sub, there all ported)

bandpass is the same, get it wrong and it will sound like crap, get it right and it will probly still sound like crap (still yet to hear one to change my mind haha)

passive radiator can sound nice but there is a lot of mucking around.

if you want perfect sub bass go an AP mat and get it over and done with.

[s_tim_ulate]

I run DD's in a sealed box for SQ. You won't have any problems.

Either option (sealed vs ported) can be EQ'd for SQ, just that low end extension below the tuning frequency will suffer in the ported box.

For straight SQ I agree with Rob go IB / AP

[Caldor]

s_TIM_ulate, on Jan 5 2006, 01:22 AM, said:

I run DD's in a sealed box for SQ. You won't have any problems.

Either option (sealed vs ported) can be EQ'd for SQ, just that low end extension below the tuning frequency will suffer in the ported box.

For straight SQ I agree with Rob go IB / AP

Exactly, in fact a vented enclosure is akin to a 24bd rolloff crossover.

I really dont like the port resonances and other noises from vented boxes.

Also you have the problem of subsonic frequencies below the tuning range over excursioning the driver and you need to run a lowpass filter to protect it should source material have stuff that low down.

[DG Phil]

Send me an email, I'll forward out this entire review. It's by Howard Doctor and appears in the Jan 2006 issue of "Performance Auto and Sound Magazine" in the USA.

Here's some relevant quotes from it:

"A couple of musicians visiting the lab while this was going on had the opportunity to listen to the DD3515d in sealed and vented modes, and the verdict was unanimous in favour of the vented set-up"

"we found the 3515d tight and solid as a sealed system, the vented system was powerful and had a very satisfying weight at the bottom end of the scale. "

"In the lab, this gave impressive amounts of throbbing bass (with a -3dB point below 40Hz), clean as a whistle sound, and enough decibels to affect your eyesight."

"the vented enclosure gives you a better bang for your buck."

Woofers that are designed for small sealed enclousres tend to have a high moving mass and weak suspension. This is not a recipe for control at high output levels. A woofer with a low moving mass, long excursion and solid suspension in a vented enclosure is hard to beat!

A woofer in a vented enclosure can deliver the same output with far less power, heat and cone excursion - all good things!

A ported box gives more "tuneabilty" to match the car's transfer function. Port noise isn't a problem if you go with our recommended 16sq" per cubic foot.

Everyone who's heard our RX8 SQ demo car has been blown away and admit it's really changed their thinking that a tiny sealed box was the path to take for SQ bass.

I too used small boxes back in the days, using mainly JLW6 and then MTX Black Golds. I wouldn't go back.

Phil

Edited by DD Phil, 06 January 2006 - 11:43 AM.