why is a ported box better than a sealed?

why is a ported box better than a sealed?

Actually, you can't say that. It's like saying a Toyota Tundra is better than an 18 wheel truck. It's comparing apples to oranges.

Where sealed or ported is better is based on usage, available power, size of the room (vehicle), etc.

In general, a ported speaker needs less power than a sealed one. It really depends on the speaker and the speaker box design on how well each performs (and the kind of music you listen to).

Alan

Actually, you can't say that. It's like saying a Toyota Tundra is better than an 18 wheel truck. It's comparing apples to oranges.

Where sealed or ported is better is based on usage, available power, size of the room (vehicle), etc.

In general, a ported speaker needs less power than a sealed one. It really depends on the speaker and the speaker box design on how well each performs (and the kind of music you listen to).

Alan
i have 2 15 inch kicker L7 sucbs being power each by a kicker kx600.1 mono block amp.Brand new pioneer deh-p250 head unit.I listen to mostly rock such as incubus,tool,nirvana.I hate trance and techno and rap in genereal but if it had ALOT of bass I'll crank it up.

It's really a matter of preference. Ported can be better than sealed but then again it depends on the circumstances. Ported are generally louder and not as clean sounding enclosures. Sealed enclosures generally provide a tight bass and sound better but not as loud. Obviously you don't care about sound quality, hence the two 15" L7's and all you want to do is shake everything within a mile radius. Ported is the way to go for you. Also, get a better Headunit :devil:

depends on your goal. sealed has a natural roll-off at lower-freq than ported. in a ported setup, you'll most likely gain more SPL around the tuning freq.

get the group delay down under 25m/s at 20hz and you'll be fine. some of the world's best companies recommended ported box for their drivers (ie. focal). ported box requires more power and motor force than a sealed box. not more power to get louder, but more power to move the cone at the same excursion as if it was in a sealed box.

sounding good is subjective to the human ears. most people don't know how to build a ported box well enough to get the sub to work at its optimal range. some people tune the port to 34hz and expect world class SQ.

take an idmax and put it in a 1.5 cube sealed box vs a 2.3 cubic feet ported box tuned to 28hz. you'll notice that the 2.3 cube ported box has more dynamics to it than in a sealed box. the sub does much better down low in a ported box than a sealed. :)

i have 2 15 inch kicker L7 sucbs being power each by a kicker kx600.1 mono block amp.Brand new pioneer deh-p250 head unit.I listen to mostly rock such as incubus,tool,nirvana.I hate trance and techno and rap in genereal but if it had ALOT of bass I'll crank it up.

Creating a *good* box is actually quite complex due to the dynamics of sound. Putting a port in or going to a band pass design basically modifies the sound curve that speaker is going to emit. Often it's trial and error.

Think of it this way (very simplified). You're familar with the bell curve for grades at school. A couple get As, More get Bs, The most get Cs, then someone has to get Ds (same number as B), and finally some get Fs (same number as number of As). (That is if the teacher forces grades to be distributed that way. Personally, I never liked this method, but it actually does represent "real" life as hard as it might seem.) The important thing is the shape of the curve - small, larger, largest, back to down to only "larger", and finally back to "small".

If this teacher gives a test and no one get's any As, then he's got to shift the grading curve so that highest person (even though they really got a B-) now gets an A. Then the next group who really got a C, are bumped up so they get a B, etc.

Well, porting or using a bandpass work like this, but in reverse. Putting in a port would be the equivalent of making sure that NO ONE gets an A and only a couple get a B. Everyone who would have gotten an A now gets a B. And those that would have gotten a B now get a C. (Actually, what really happens is that anyone who would have gotten an A is removed from the class so their grade really doesn't even matter any more in the big picture. Everyone else gets to stay in.)

So what happens is that a ported speaker will be more efficient for certain frequencies in the lower ranges. The tradeoff being that it won't be very good at transmitting frequencies in the higher range. So this makes it more efficient if you want the lower frequency notes and don't even care about the higher ones. (You've got another speaker that's handling the higher ranges).

A sealed speaker box is like a "normal" grade distribution (full spectrum - majority in the middle) where a ported speaker is like a shifted grade distribution where the higher performers are eliminated, or weakened so much that you don't even know they exist (majority in the lower). This lets the energy then be concentrated on the lower frequency areas.

People that really like pounding bass oriented music, they tend to really like band pass (ported on steroids) or ported speakers because in the really low ranges (where you can hear them even though you can't see the vehicle yet) they really crank and you don't need huge bass amplifiers (like you would for a sealed box).

The downside to porting or bandpass (since they don't transmit the higher bass frequencies well) is that you can get holes in your music if you don't compensate. That is you get the real low bass but don't get the upper bass and your midrange speakers start to pick up at yet a higher frequency. So you totally skip over a frequency range. If your music isn't really much in that range though, you don't even notice much (or at all).

The big advantage to porting or bandpass is that you don't need as large an amplifier to get the same amount of bass sound (in certain ranges). The downside is that the actual bass isn't balanced. The higher ranges are weakend while the lower ranges are strengthened (for the same amount of power).

Oh, one more thing. In a sealed box when the speaker goes in it's hitting [now] compressed air and the compressed air is pushing the speaker back out. When the speak is going out a vacuum is being created in the box and the air is trying to pull it back in. Kind of like having an air shock absorber. That's why it's "tighter" - more appropriate for classic music, country, vocals, etc.

There is very little vacuum in a ported or bandpass box because of the "holes". The compression\vacuum effect is practically nil unless the speaker is moving so fast that the air doesn't have time to rush in or out the holes. As a result the speaker "bounces" around more (just like a car with no shocks) so it sounds boomier.

Now you can see why a ported speaker needs less energy. Which would you rather get "a rockin' "? Pushing up and down on the bumper of a car that has no shocks (ported speaker) or one that has a strong, efficient shock absorber on it (sealed speaker). The first is much easer to get moving up and down. In a speaker the larger the movement, the larger the sound wave, and the more bass sound it's going to emit. But the tradeoff on a speaker is that you don't have the tight "maximim movement" control over the speaker movement in a ported box like you do in a sealed box. And the upper effective range of a ported speaker drops for the same same exact speaker (which might be fine if you're compensating elsewhere or just don't care).

Alan

ok... i have to tell you akauth... when i first started reading your post, i was COMPLETELY lost as to where you were going with that... then as i read on, it pulled itself together. good analogy by the way. :cool:

http://www.jlaudio.com/tutorials/magic/index.html