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cockeyed00
01-28-2003, 01:44 PM
I just wanted to know that the difference between a bandpass and a sealed box and how much does porting a box effect it?
thanks
Jon

Randy Savage
01-28-2003, 03:00 PM
Originally posted by cockeyed00
I just wanted to know that the difference between a bandpass and a sealed box and how much does porting a box effect it?
thanks
Jon If it is a prefab bandpass box(one that was generically built), then sealed is much much better. Generally speaking, sealed boxes are for more tight, accurate bass. Ported boxes are for SPL, more boomy, loud bass.

nick3470
01-28-2003, 05:33 PM
one rule of thumb, bandpass(unless made perfectly) ****

SoundsUnlimited
01-29-2003, 12:43 PM
I think bandpass box's **** ***..They really restrict u on everything SQ/ SPL...Sealed boxes are much tighter nad accurate and can generally be used for Clean bass(SQ)..Ported box increase more air-flow which in return with give u a great DB rating so therefore ported boxes help the subs to move more air and increasing the SPL..But remember with ported boxes, they are much more complicated and requre the right tuning requency for the subs/ and for box size in order for the ported box to work properly, NEVER BUY Pre-FAD vented box's..Even though box is ported..if the sub needs a 3.5 tuned to 45 hz and u have a box which is 1.5 tuned to 65hz..That sub Aint gona do ****..So u got to know the specs on the sub and the type of vehicle to matcht he PERFECT ported box, but if done correctly can be MOST PLEASING..So good luck, and if u need any additional help, sned me a IM on AIm

Good luck,
Blake

cockeyed00
01-29-2003, 05:01 PM
Okay, if sealed boxes are for tight accurate bass and ported are for boomy bass that means that:
sealed = boom
ported = boooooom

it holds a longer note?

Where would you determine whether to use a bandpass or sealed? When would you say, "...okay, for this set up you should use a bandpass..."? What benefits are there when using a bandpass and using a sealed? what is SQ? and SPL?

thanks
Jon

Randy Savage
01-29-2003, 05:05 PM
Originally posted by cockeyed00
Okay, if sealed boxes are for tight accurate bass and ported are for boomy bass that means that:
sealed = boom
ported = boooooom

it holds a longer note?

Where would you determine whether to use a bandpass or sealed? When would you say, "...okay, for this set up you should use a bandpass..."? What benefits are there when using a bandpass and using a sealed? what is SQ? and SPL?

thanks
Jon If you are new to car audio, I would strongly suggest staying away from bandpass boxes. They are extremely difficult to build and to tune properly. You pretty much stated the benefits of a sealed box, tight and accurate bass notes. A ported box will have more boomy bass notes. Usually choosing between a sealed and ported box is deopendant on the owners personal taste and the sub. Say you have an Alpine Type-R sub, most people would recommend a sealed enclosure for this because it is mainly a SQ(sound quality) sub. However, say my subs, Audiobahn AW1206Q, this is mainly a SPL (sound pressure level) sub, which is strongly recommended for ported enclosures. Hope this helps.;)

cockeyed00
01-29-2003, 06:59 PM
thanks for all the info guys. No one really explained that much about bandpass though. All that I got was they are hard to tune, hard to make. Don't getme wrong, everyone was real helpful, I am just the type of person that wants to know how things work and why. My buddy's friend has an integra and said"...I'm not sure whether to put a bandpass box or a sealed box...." in my head, I was like.."...what's the difference?.." that's why I wanto know.
If anyone can help......
thanks
Jon

ChefJoe
01-29-2003, 10:28 PM
Sigh, ok, find some speaker specs, go to www.linearteam.dk >isdonline >new driver and use their on-line calculator to find the optimal bandpass, ported, and sealed boxes.... look at the little diagram that does frequency vs level. What you'll see is that the proper bandpass box is a little louder at lower freqencies than the other types of boxes... and cuts off at higher frequencies (which would, in theory be great... less interference noise). The sad thing is when you adjust the volume of the front chamber, the volume of the back chamber, or even the frequency of the box by less than 10% (yeah, that's not much when you're talking about a .6 cft space) you can redraw the line and see the level goes all wavy at the top (not what we want, flat response throughout the range you want to reproduce is desired in speakers). By adjusting all the levels by less than 10%, I was able to get the 50-60 hz range to jump by 3 db (which is a little more than doubled) at the expense of the low end response. this is why they're incredibly tricky to build.

Bandpass relies on frequency cancellation to get an even response, if you're off just a little bit, the cancellation doesn't work out even, and you're screwed. I'm about to ditch my crappy bestbuy bandpass box in favor of ported (sigh, the things I did in high school).