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post #1 of 9 Old 01-10-2019, 07:16 PM - Thread Starter
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UM18 question

Do i need a hpf while running 2 um18s each in 4.22 cuft sealed box by EP4000?
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post #2 of 9 Old 01-10-2019, 09:09 PM
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Most people prefer a 30hz shelf boost for sealed, to be flat to single digits.

But with only 2 18's, depending how how loud you intended to blast it, it is "possible" to run out of xmech or coil cooling;
and hpf might help with bottoming.
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post #3 of 9 Old 01-10-2019, 09:41 PM - Thread Starter
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Quote:
Originally Posted by BassThatHz View Post
Most people prefer a 30hz shelf boost for sealed, to be flat to single digits.

But with only 2 18's, depending how how loud you intended to blast it, it is "possible" to run out of xmech or coil cooling;
and hpf might help with bottoming.
Thanks BTH
I got minidsp 2x4 hd on hand too but not sure how it will work out with its input sensitivity being 2v where my avr x4400h outputs less voltage from sub out


2x4hd output might not be an issue for ep4000 input.
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post #4 of 9 Old 01-10-2019, 10:20 PM
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If it’s for home theater use head over to the bass eq for filtered movies thread. Sealed you might not need any other eq for movies depending on your room. Pretty much turned off my house curve for movies if using beq, my room is smallish, ymmv.


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post #5 of 9 Old 01-10-2019, 10:23 PM
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I am looking at doing 2 UM18s sealed off a Denon 4400 with a minidsp 2x4HD for any needed correction.
The benefit of sealed is stronger low freq. Vented would be louder.

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post #6 of 9 Old 01-11-2019, 12:45 AM
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Quote:
Originally Posted by nexus99 View Post
I am looking at doing 2 UM18s sealed off a Denon 4400 with a minidsp 2x4HD for any needed correction.

The benefit of sealed is stronger low freq. Vented would be louder.
That's the exact setup I have. Check my posts for the build thread.

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LG OLED55C6P, Denon X4400H 5.2.4, HSU 5.1 speakers, 2x18" Dayton Ultimax sealed, MiniDSP 2x4 HD, Pro-LITE 7.5 amp
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post #7 of 9 Old 01-11-2019, 06:03 AM
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Quote:
Originally Posted by Rcris View Post
Do i need a hpf while running 2 um18s each in 4.22 cuft sealed box by EP4000?
You don't need an HPF for those. You might need EQ to boost the low frequencies, but you won't need to cut them (HPF). It's the nature of sealed enclosures to restrict the cone movement at low frequencies (assuming the box volume is set correctly for that driver). I've got two UM18's in the PE 4cuft flatpacks. I ended up using a HS (high shelf) filter with negative gain; essentially boosting the low end. No issues.
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post #8 of 9 Old 01-11-2019, 06:29 AM
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A sealed design of reasonable size doesnt need an hpf but could still be damaged from over excursion down low, especially if boosting. I would suggest calibrating for worst case scenario with something like War of the Worlds.

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post #9 of 9 Old 01-11-2019, 08:09 AM - Thread Starter
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Quote:
Originally Posted by Vince_B View Post
If it’s for home theater use head over to the bass eq for filtered movies thread. Sealed you might not need any other eq for movies depending on your room. Pretty much turned off my house curve for movies if using beq, my room is smallish, ymmv.


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wow thanks for posting that thread info, will certainly go through it. Well this is not for my room and a couple of infi1262 places in the corners really rocked the room. If infi 1262 were able to handle the EP4k then why can't UM18s with no EQ or HPF . Just bcoz this is for my friends place I want to be on safe side.

Last edited by Rcris; 01-11-2019 at 08:13 AM.
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