Sealed or Ported Boxs

 

New member
Username: Ryanoc

Post Number: 6
Registered: May-05
I had a ported mtx box with a compvr 12 kicker but had to return it because it smelled like a barn. I got a qlogic box that lets me choose between ported and nonported (it comes with a cap for the port) It realy sounds good both ways, but I think the sealed configuration is better. What is everyones oppinion on ported or sealed?
 

New member
Username: Adelphia83

Colorado Springs, CO USA

Post Number: 1
Registered: May-05
I've done both routes, not with the same woofer albeit, but my own experience mimics that of the general concensus.

Sealed boxes have excellent transient response which equals sound quality. Power handling is increased with a sealed box, but this is largely dependent on the size of the enclosure. I used two Audiobahn Alum12 woofers in sealed enclosures (1.25cf each with polyfill), and the sound quality was amazing. SPL was decent, about what I'd expected given the power I was pushing to the two subs (240w x 2). This combo was excellent with just about any music type.

For my next system, I chose seperate ported enclosures at 2.0cf each, with Audiobahn AW1200Q woofers installed. Port tuning makes all the difference in a ported application. I chose to use a happy medium between the manufacturers recommendations, and my own based on the theile small parameters. The port was tuned at 38.5hz.

Power was increased to 400w RMS per channel. This combo has some serious SPL, more than I was expecting. Sound quality is adequate but nothing outstanding. Most music sounds awesome, but occasionally you get the punchy type rock sound with varying frequencies, which is lacking. But overall I was very impressed.

Personally having used both types of enclosures, I'd used ported again. You are essentially creating SPL for free, and the SQ can be just as good if you know what you're doing. The only cons I can think of, is that the required enclosure size is generally much larger when using a ported box. Also some woofers are not best suited in ported enclosures, and vice versa.
 

Silver Member
Username: Lbeckner

Tulsa, Ok Usa

Post Number: 397
Registered: Oct-04
Its all about preference. Ported should be a little louder usually with a loss of sound quality. Woofers in sealed enclosures have better power handling capabilities.
 

DUB
Unregistered guest
hey what is pollyfill for?
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3911
Registered: May-04
About power handling, ported has higher power handling than sealed does above tuning. Plug a sub into WinISD and look at the excursion differences for an example. The activity of the port dampens the sub and limits cone excursion greatly, and also the transfer of air aids in cooling the voice coil. It is only when ported is below tuning that it has lower power handling than sealed.

Sealed has better transient response and phase response than ported, but it does have drawbacks. First, when you have reached the system resonance, the cone loses control and is thrown into high excursions (this is usually where you'll hit x-max in a sealed box other than very low frequencies). With those high excursions, high distortion also occurs, and this usually occurs in the 40s and 50s, which is the meat of the lower bass region. It's very noticeable at high volumes, especially with subwoofers that have a parabolic BL curve (less motor strength at high excursions).

Ported has worse transient response than sealed and since the port isn't in complete phase with the woofer, some phase anamolies (cancellation and boost) at certain frequencies occur. At any frequency above tuning, ported enclosures have lower distortion than sealed enclosures due to the superior mechanical control of them. This is especially noticeable at high volumes, you'll notice an audible difference between ported and sealed at high volumes, that difference being that ported will be cleaner, especially at low frequencies. Another benefit is that at the systems resonance, your excursion is at it's lowest unlike sealed, equating to lower distortion. With ported, you lose control of the driver below the tuned frequency, having the same effect as an infinite baffle enclosure and risking overexcursion if taken too far down. A subsonic filter is required to counter that.
 

New member
Username: Adelphia83

Colorado Springs, CO USA

Post Number: 3
Registered: May-05
Polyfill helps to eliminate any standing waves that might be generated by upper ordered harmonics (caused by distortion) in the enclosure. In general tt reduces high frequency resonances.

It also helps to increase subwoofer efficiency by dissipating some energy that affects the sub, particularly the voice coil.

In addition it "fools" a sub into thinking it is in a bigger box. For this effect, you have to play around with different amounts of polyfill within the enclosure.

I have tried using polyfill and without, and the SQ is definately improved with the addition of some dampening material.
 

DUB
Unregistered guest
So it would be a good idea to have some pollyfill then? where can I find some?
 

New member
Username: Adelphia83

Colorado Springs, CO USA

Post Number: 8
Registered: May-05
Just get some pillow stuffing from Walmart or your local crafts store.
 

Silver Member
Username: Rzarector

Coquitlam, Bc Canada

Post Number: 292
Registered: Dec-04
jonathan it always seems like your hating on the sealed boxes..you get so defensive when someone lists a negative point about a ported box :p
 

New member
Username: Adelphia83

Colorado Springs, CO USA

Post Number: 10
Registered: May-05
I think his post was right on the money.

Sealed boxes can be easily obtained and setup, while ported requires a knowledge of the subwoofers parameters, specific port tuning, and a subsonic filter among other things.

But while a ported system may cost more money in the long run (again some subs still won't be happy in a ported enclosure), it generally gives you SPL for free, with little expense of sound quality when done right.
 

Gold Member
Username: James1115

Wilton, Ct

Post Number: 2900
Registered: Dec-04
Jonathan runs a sealed box for his ID max:-)
 

Gold Member
Username: James1115

Wilton, Ct

Post Number: 2901
Registered: Dec-04
its prob cause of lack of room to go ported though lol!
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 3919
Registered: May-04
It's just that ported has the most misconceptions. Trust me, I respect the pros and cons of both, both offer good results, it's all in what you want. I do use sealed in my truck, it's because of limited space and also my goals for the system. I am not a huge SPL fanatic, sealed does the trick for me. Ideally I'd go AP, but not an easy task or a practical one for a truck.
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