PDA

View Full Version : What's the difference in sound?



bonbon989
07-06-2004, 01:25 AM
Hey,

I currently have my 10" sub in a 1.25 cubic foot sealed enclosure. I was just wondering what the difference in sound is between sealed, bandpass, and ported enclosures? Thanks for listening! :patriotic

BIG_SUPERMAN72
07-06-2004, 01:31 AM
it will be much better in ported.

violator5spd
07-06-2004, 07:07 PM
Hey,

I currently have my 10" sub in a 1.25 cubic foot sealed enclosure. I was just wondering what the difference in sound is between sealed, bandpass, and ported enclosures? Thanks for listening! :patriotic

It can depend a lot on the type of sub you have. Not every sub will work well and all 3 types of enclosures. Here is some text I got from Crutchfield's website, a nice little overview...

Sealed boxes: For deep, precise bass
A sealed box is an airtight enclosure housing your subwoofer. A sealed box is best for any music that demands tight, accurate bass. Expect flat response (not excessively boomy), deep bass extension, and excellent power handling. Since a sealed enclosure tends to require more power than a ported box, use an amplifier with ample wattage for optimum performance.

Ported boxes: For forceful bass
Ported boxes use a vent (called a port) to reinforce low bass response. You get more output than you would from a sealed box at any given amplifier wattage. Some people prefer the sound of ported boxes for rock, heavy metal, or any hard-driving music. Ported boxes can deliver deeper bass than sealed boxes, though they need to be much larger than sealed enclosures to accomplish that.

Bandpass boxes: Maximum slam!
Bandpass boxes are a special type of ported box designed for maximum slam. The woofer is mounted inside a dual-chambered box (one chamber sealed, the other ported), with the sound waves emerging from the ported side. The sound that comes out of the port is extra loud within a narrow frequency range. Because bandpass boxes are super efficient within that range, they tend to boom. Their aggressive sound is great for rap, reggae, and hard rock. Not all subwoofers work well in bandpass boxes, though.

helotaxi
07-07-2004, 12:44 PM
You got it from Crutchfield, so I won't blame you for the inaccuracy and glaring generalizations. Some clarifications:

Sealed: It all depends on the sub and the enclosure and the relationship between the two. In an optimum enclosure the sub will play as accurately as it possibly can. In an enclosure that is too small, it will have a peak in the response just before it begins to roll off on the bottom end. You will lose some low frequency extension as well. A bit of a peak is not that big of a deal in the car, nor is the higher (realtive to a ported enclosure) half power point. The transfer function of the car will fill in the lower octaves very nicely. With too big of a peak the sub will sound boomy through that frequency range. Too big of an enclosure will help with efficiency, but will cost you power handling and will give you bass that sounds sloppy as there is not enough control of the speaker cone exerted by the enclosure.

Ported: Again, a lot depends on the sub and the enclosure. A ported enclosure plays flatter to a lower frequency (ususally by 15-20 Hz) than a selaed enclosure but rolls off twice as fast below that frequency and is not giving accurate output below the tuning frequency. They provide additional output compared to a sealed enclosure typically from around 30-50hz which is where most rock and rap center most of their bass energy (kick drum, low end of the bass guitar, synth bass, etc...). This frequency range is amplified even more by the transfer function of the car and makes it seem like the ported enclosure plays lower bass better. For my definition of low bass, a ported enclosure doesn't do it justice. I have several CD's with a decent amount of information well below 30Hz. My XXX in a ported enclosure pretty much just flops around on those notes whereas the sealed enclosures I've had in the past would actually play the notes. I am running my sub in a fairly low power application and the ported enclosure makes a huge difference on most music allowing it to give good impact and get pretty loud without a lot of power. You can play with the enclosure design of a ported enclosure a good bit to adjust the sound but once you get away from the few basic optimized alignments, the accuracy of the output will suffer greatly. The tuning of the enclosure can be manipulated higher to help efficiency and combined with a large box will yield excellent SPL, but at the cost of anything resembling accuracy or low extension. Basically a one-note box. If you try to push the tuning frequency lower than optimal, you basically end up with a sealed enclosure and lose most all of the benefits of a ported enclosure and it still rolls off sharply below tuning. To get a ported box that plays REALLY low, you need a sub with a REALLY low resonant frequency and the huge enclosure that a low Fs dictates. This is not practical for most car applications.

Bandpass: You can make a bandpass sound pretty much however you want it to sound. A 4th order (one chamber sealed and one ported) can be made to behave like a sealed box with slightly better efficiency through the pass band at the cost of transient response and box size. You can make it really efficient at the cost of passband width and transient response. You can make it have great transient response and accuracy but it will be less efficient than a ported design. A bandpass is basically one huge compromise. To get one benefit you sacrifice on several other areas. The difficulty of designing and building a proper bandpass box for a given sub compounds this even further. The tuning must be perfect. The volumes must be perfect. Mess up even one measurement a tiny fraction and your great design turns into a large paperweight. A 6th order box (both chambers ported) can sound great and get loud. Again you have the tradeoffs, though. A great sounding 6th order box is going to have a fairly limited passband (1 maybe 2 octaves depending on the desired efficiency) and will be huge. For both types you have to factor in the complete lack of midbass response and the execution of the design gets even more difficult. You must have a great set of midbasses to even think of being able to integrate a bandpass into a system intended to play music if you plan on getting any of the efficiency benefits of the bandpass design. The final result is almost never worth the trouble when compared to a more conventional sealed or ported design. Bottom line is unless you have a lot of time and energy and MDF to burn getting the design right and working on the system integration, stick with sealed or ported.

Berry47
07-07-2004, 02:19 PM
it will be much better in ported.

This is 100% subjective. I prefer tight accurate bass so I use sealed boxes. As other posts say, it largely depends on the type of sub and the music you listen to.

helotaxi
07-07-2004, 06:00 PM
My sub is in a ported box and I would challenge you to audibly distinguish it from a sealed box without prior knowlege of which was which. Once you get to really low frequencies it becomes more obvious, but with an optimum tuning, the difference is almost inaudible through the normal music frequencies. I was a big proponent of the sealed box for accuracy myself until I gave this a try.