Ported, bandpass...difference???

polkaudiosupra101

can someone please explain the difference between a ported box and a bandpass box? and which would be better for my 88 supra? thanx.
scott

polkaudiosupra101

cmon i know someone reading this knows the difference and can take the time to explain

TroyD

Sorry! I would venture to say that most of the guys on this side of the fence are all HS/HT guys. The guys that are into car audio scope out the infield as well.

Russman is somewhat into ca but he hasn't been on the forum much of late.

Troy

TrappedUnder Ice

Band pass is tuned more to a frequency and accents that crertain frequency. While you tune all boxes... a banpass is more dedicated to that certain frequency. Both ported and bandpass boxes are sloppy....ported being louder spl wise and taking less power for the spl.... the bottom line is you want to tune the box to your cars (darn..it just left my mind) but your car will be loudest at a matched frequency....it has a certain name..but cant it just left me.

I have never been a fan of band pass boxes. I favor sealed wich result in a tighter hit- but takes more power...

ported would be better iMO than a bandpass

ha...just remembered- tune it to your cars resonant frequency. I dont know the formula... but on sounddomain.com..they can help ya out there...

polkaudiosupra101

anyone there?? i know yall know this stuff because its an easy one. but when i ask hard questions everyone loves to jump on my q? c'mon. i mean.....c'mon

RuSsMaN

TUNED PORT ENCLOSURES
The tuned port enclosure is similar to the acoustic suspension box
except that it uses a port to take the back wave from the speaker and “tune” it to reinforce the front wave. A system becomes more efficient when the frequencies of the port and the front wave are in phase. It is absolutely critical that the dimensions of the box and the port are perfect, or the back and
front waves will cancel each other out, reducing your bass output. Tuned port enclosures tend to be peaky in the bass, and many people (particularly Bassheads) like the punchiness of the sound. Tuned port enclosures roll off at a very steep 18 dB per octave below cabinet resonance, which means that the room gain of the car will not help to extend the lowest of frequencies. In addition, the woofer becomes “unloaded” below the tuning frequency of the port and very loud musical information below these frequencies can damage a woofer.

BAND-PASS ENCLOSURES
Band-Pass boxes can be built in a near infinite amount of
configurations. They incorporate at least two individual chambers and are by far the most complicated box to model and build. The theory behind band-pass boxes is to limit the frequencies
produced by the subwoofer, thereby making it more efficient in the frequencies that it produces. A by-product of this efficiency is that it is often possible to build a band-pass box much smaller
than its equivalent acoustic suspension box and get the same quantity of acoustic output. If you have a very small car with limited room for a subwoofer box, a band-pass box may be a good choice. The downsides of the band pass box are numerous. First, the construction must be flawless, any airleaks or rattles will seriously degrade performance. Second, designing band-pass boxes is as much art as science, just because a computer
program says that a certain design will work is no guarantee that you will like the performance of the finished design. Third, all subwoofer enclosures exhibit a phenomenon known as “group delay”. It means that the sounds from the subwoofer will lag in time from the sounds created by your high frequency speakers. This causes a smearing of the sound and in worst cases a ping-pong effect from the highs in the front of your car to the bass in
the rear. Band-pass boxes are especially prone to long group delays. Finally, the pressures and vacuums formed within a band-pass box can be extremely high, if the subwoofer you
are utilizing does not have a very stiff cone. It can buckle under the high pressures, making very bad noises.

Polk subwoofers utilize thick mineral filled cones, and are extremely well suited for use in band-pass enclosures.

I prefer sealed or ported for home use, and bandpass or sealed for car use. Polks are best sealed or bandpass, period.

Cheers,
Russ

polkaudiosupra101

now.......... to bandpass or to seal ha ha ha ha haaaaaaa haaaaaa (mad scientist laughter)