Sealed Enclosure Or Free Air ??
Thread Starter
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
Sealed Enclosure Or Free Air ??
I'm no guru, but I do love good clean sound. 
I am upgrading my front stage to Focal K2 165KP and am looking for help deciding on sealed or free air installation.
The speakers will be powered with 75 watts RMS each and will be mounted in my 86's doors.
Your thoughts
I am upgrading my front stage to Focal K2 165KP and am looking for help deciding on sealed or free air installation.
The speakers will be powered with 75 watts RMS each and will be mounted in my 86's doors.
Your thoughts
Team Owner
Joined: Feb 2000
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From: Sacramento CA
Well it depends on the speaker, I thought you had the K2P mids which I've seen sound really good with a sealed box.
Focal will send you specs on a sealed box.
With a sealed box you have some advantages:
*Protects speaker from the environment.
*Significantly reduces, if not eliminates, door rattles.
*Cleaner midbass, as you won't be using the door as an enclosure.
*Less midrange/midbass resonance. The Corvette door is horrible for this.
Some speakers designed for car audio need ridiculous sealed enclosures to perform well. I would email Focal and ask what size they recommend and see if it is feasible.
Focal will send you specs on a sealed box.
With a sealed box you have some advantages:
*Protects speaker from the environment.
*Significantly reduces, if not eliminates, door rattles.
*Cleaner midbass, as you won't be using the door as an enclosure.
*Less midrange/midbass resonance. The Corvette door is horrible for this.
Some speakers designed for car audio need ridiculous sealed enclosures to perform well. I would email Focal and ask what size they recommend and see if it is feasible.
Pro
Joined: May 2007
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From: WayTooCloseToNY Northeast PA
Assuming you're using these in conjunction with an sub actively crossed, there's little difference in the style of mid enclosure. To put it plainly, the mid won't be reproducing frequencies at any substantial level that could be affected by the enclosure type.
More detail on your setup would make for a better answer.
More detail on your setup would make for a better answer.
Team Owner
Joined: Feb 2000
Posts: 51,504
Likes: 6
From: Sacramento CA
Assuming you're using these in conjunction with an sub actively crossed, there's little difference in the style of mid enclosure. To put it plainly, the mid won't be reproducing frequencies at any substantial level that could be affected by the enclosure type.
More detail on your setup would make for a better answer.
More detail on your setup would make for a better answer.
To the OP:
Very easy test. build a small enclosure with 1 speaker in it. The other, put it in the door. Compare them.
especially with some metallica. the midbass resonance in a door is excruciating.
Pro
Joined: May 2007
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From: WayTooCloseToNY Northeast PA
My C4s never had that problem, and it's not across-the-board in all doors. If isolation from the door is a concern, try some large-diameter PVC tub capped off on the back end and filled with something more dense than polyfill. Drivers the size of the 165 don't require much space, and again, if there is a sub(s), the size of the enclosure really won't matter.
Team Owner
Joined: Feb 2000
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From: Sacramento CA
Didn't realize we were addressing problems before they existed.
My C4s never had that problem, and it's not across-the-board in all doors. If isolation from the door is a concern, try some large-diameter PVC tub capped off on the back end and filled with something more dense than polyfill. Drivers the size of the 165 don't require much space, and again, if there is a sub(s), the size of the enclosure really won't matter.
My C4s never had that problem, and it's not across-the-board in all doors. If isolation from the door is a concern, try some large-diameter PVC tub capped off on the back end and filled with something more dense than polyfill. Drivers the size of the 165 don't require much space, and again, if there is a sub(s), the size of the enclosure really won't matter.
Thread Starter
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
Pro
Joined: May 2007
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From: WayTooCloseToNY Northeast PA
There's no such thing as a weak/strong midbass in terms that apply here, and factory speakers are a poor choice of comparison when you consider they're deliberately excessive in the midbass region in order to give the casual listener the perception of more bass.
There are a number of factors which play into this problem. They include the driver's parameters (Qts, Fs, Qm and Vas) and distortion characteristics, the door shape and volume, how well-sealed the door is, how well damped it is, the baffle material used and even where mechanical components are bolted. Crossover type, point and slope also play a huge role. That's why these things don't always exist, and vary in intensity when they do.
I happen to have a 165 driver sitting on the bench in my basement, so I'll get some quick numbers.
And, FWIW, in Komoman's C6 system we did NOT have this problem. In fact, I believed his front-stage midbass to be one of those components' strong points.
There are a number of factors which play into this problem. They include the driver's parameters (Qts, Fs, Qm and Vas) and distortion characteristics, the door shape and volume, how well-sealed the door is, how well damped it is, the baffle material used and even where mechanical components are bolted. Crossover type, point and slope also play a huge role. That's why these things don't always exist, and vary in intensity when they do.
I happen to have a 165 driver sitting on the bench in my basement, so I'll get some quick numbers.
And, FWIW, in Komoman's C6 system we did NOT have this problem. In fact, I believed his front-stage midbass to be one of those components' strong points.
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Pro
Joined: May 2007
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From: WayTooCloseToNY Northeast PA
With an appropriate crossover, I don't believe you should have any problems beyond notoriously lousy weatherproofing of the C4 doors. If you do, post #5 will fix the vast majority.
Team Owner
Joined: Feb 2000
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From: Sacramento CA
I'll start another thread later with some music samples... now im real curious. You dont hear it in all music, but definitely in stuff that has the bass guitar's mix pretty heavy. If you have Metallica's Better Than You on disc, check it out. (with eq off)
Last edited by Kale; Dec 13, 2007 at 04:04 PM.
Pro
Joined: May 2007
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From: WayTooCloseToNY Northeast PA
Hearing it and measuring it are two vastly different things. Human hearing is far from reliable.
Last edited by Spkrboy; Dec 13, 2007 at 04:09 PM.
Thread Starter
Team Owner
Joined: Jan 2003
Posts: 20,324
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From: Summerland B.C. Canada
Thanks for the help, guys.
Team Owner
Joined: Feb 2000
Posts: 51,504
Likes: 6
From: Sacramento CA
Thread Starter
Team Owner
Joined: Jan 2003
Posts: 20,324
Likes: 250
From: Summerland B.C. Canada
Made a decision
Not going with a sealed box, sealed door instead. Looking at Focals specs, they suggest 30 litres. Ordered another 50 sq. ft. of deaden-er and will add another layer to doors and do the floor boards and tunnel with the rest(back half is done).
Also decided, if I feel that 75 per channel is not getting them to their potential, I'll bridge my JL and get another amp for the subs.
Looking forward to spring.
Not going with a sealed box, sealed door instead. Looking at Focals specs, they suggest 30 litres. Ordered another 50 sq. ft. of deaden-er and will add another layer to doors and do the floor boards and tunnel with the rest(back half is done).
Also decided, if I feel that 75 per channel is not getting them to their potential, I'll bridge my JL and get another amp for the subs.
Looking forward to spring.