Good idea to close the port on a vented 8-inch 2-way ? - diyAudio
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Old 10th December 2007, 04:26 PM   #1
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Default Good idea to close the port on a vented 8-inch 2-way ?


I have Paradigm 8-inch 2-way speakers. They are in a fairly large cabinet so they have bass extension below 50 Hz. I want to add a subwoofer or possibly a pair and also a high pass for the Paradigms.

My question is: would blocking the port on the Paradigm speakers make a smoother roll-off so that subs can be more seamlessly mated with them ? Do you think that there could be other (negative) affects if I did this ?


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Old 10th December 2007, 04:28 PM   #2
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Your speaker was designed as a ported enclosure and you should not just close off the port. A sealed box for the same drivers would be much smaller than what you have. Impedence curves would change and your results would be unpredictable.
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Old 10th December 2007, 04:50 PM   #3
Dan2 is offline Dan2  South Africa
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stick something nice and heavy next to your enclosure so it blocks off the port and see if u like how it sounds

but if you are going to use a high pass filter then you may not have to do anything with the box
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Old 10th December 2007, 06:33 PM   #4
BHTX is offline BHTX  United States
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Resonances in the mids. Close it. Or, get/build new speakers. Place the sub properly, make proper phase adjustements, set the crossovers where they should actually be, and EQ as necessary to obtain the closest possible match to the Paradigms, or whatever speakers you're using.
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Old 10th December 2007, 07:47 PM   #5
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"Resonances in the mids. Close it."

Are you saying that I have resonance in the mids now because it is a vented box and that I should close the port ?

I am not findings much of a consensus here about whether closing a port on a speaker that is designed as a vented inclosure will introduce problems or if it will just make the bass cutoff smoother at 24 db from the cabinet resonant point downward. I can deal with the lost bass, especially if the now closed cabinet would give tighter midbass and mids, because I would be adding a sub or two. I can't deal with new, weird colorations caused by closing the port.


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Old 10th December 2007, 07:59 PM   #6
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Stick a sock in it and call it aperiodic. No I'm not kidding.

I often put a sock in the Paradigm Titans (6.5" 2 way) when using it with a powered woofer. Helps damp the cone movement when running them hot. If I ever decide to keep it that way, I will consider adding some filler to the box and make the volume smaller.

Or not... YMMV
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Old 10th December 2007, 09:46 PM   #7
BHTX is offline BHTX  United States
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Adding to my previous post, I agree with Cal, and have done the same thing several times in the past with smallish vented bookshelf speakers. Works fine. As far as "weird colorations caused by closing the port", I can tell you that there's probably far more 'colorations' from simply having that port than anything. The way I see it, ports are usually a sacrifice to get more bass from a specific driver. It often causes problems in other areas that need to be addressed, especially resonances in the mids from the box and port that need to be carefully damped just to reduce these problem areas.

Anyway, yeah, put a sock in it.
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