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Hi guys.


I hope everyone is good.


What's the exactly different between the compact and the ported subwoofer ?


And what's the preferable to you if you need to buy a subwoofer ? Ported or compact ?.


Many thanks friends.

 

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Compact = sealed.


Roughly speaking:

- a ported sub will have more output around its tuning frequency than a sealed sub will have at similar frequencies;

- a sealed sub rolls off more slowly than a ported sub, and may benefit more from room gain to extend lower than a ported sub;

- a sealed sub may have more output at higher frequencies than a ported sub; and

- very generally speaking, ported subs work better (provide more output) than comparably powered / sized sealed subs in larger rooms.
 

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I was playing with an online speaker calculator and made this comparison which should illuminate the matter nicely.



[log frequency scale: 10^1 stands for 10Hz, 10^2 stands for 100Hz]


The optimal ported box is a lot larger than the optimal sealed box, goes lower into the bass without rolling off, but then rolls off faster than the sealed box. At some point in the subbass it would have rolled off further than the sealed sub. Whether the sealed sub has enough power to make this theoretical low bass extension stick is another matter (look at the crossing points between the black and blue lines; the ported sub is stronger than the sealed sub from 100Hz on down to about 15Hz, at which they cross over again. But by then both subs are already down nearly 20dB, so the better extension of the sealed sub may be academic at best)


A lot of subs come with multiple ports, which you can plug to extend the bass extension. The red line simulates the ported sub with 2 of its 3 ports plugged, equivalent to the "maximum extension" mode advertised on some brands. The bass rolls off at a high frequency similarly to a sealed sub but rolls off more slowly than either the sealed or ported sub, such that its response is greater than both of them at some point in the subbass.
 

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Quote:
Originally Posted by Joe0Bloggs  /t/1468818/compact-and-ported-subwoofers#post_23218123


I was playing with an online speaker calculator and made this comparison which should illuminate the matter nicely.
Unfortunately that's a vast oversimplification, and much of it isn't true. The choice of vented versus sealed is mainly determined by the driver T/S parameters. Depending on the driver you can even arrive with virtually identical response with the same driver and box size sealed or vented.

The question of which is best for a particular application can be answered with sufficient data, but that data can be very hard to find. Data-bass.com is one good source.
 

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Quote:
Originally Posted by Bill Fitzmaurice  /t/1468818/compact-and-ported-subwoofers#post_23218999


Unfortunately that's a vast oversimplification, and much of it isn't true. The choice of vented versus sealed is mainly determined by the driver T/S parameters. Depending on the driver you can even arrive with virtually identical response with the same driver and box size sealed or vented.

The question of which is best for a particular application can be answered with sufficient data, but that data can be very hard to find. Data-bass.com is one good source.

Sounds fun--can you give an example set of T-S parameters that would give such a result?
 

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I would checkout the DIY section and download Winisd and play around with the parameters for various woofers.


I would actually work the other way and tell you to determine what size subwoofer you can fit in your home. Along with that we need to know how large your room is, and your budget. Those three factors can help determine if you should go ported or sealed. 12", 15" woofer, or 18" woofer. Some drivers can model pretty well in both ported and sealed modes, but if you can't fit a big ported box in your room, sealed might be the best way to go.


Hope this helps.
 
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