Sealed vs Marty Sub Response - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 9 Old 12-03-2019, 03:26 PM - Thread Starter
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Sealed vs Marty Sub Response

I just built one full marty to test and am getting a huge dip in response for some reason. Both subs are Stereo Integrity HT18s - full marty vs 4cf sealed, no EQ. Blue line marty, red line sealed, placed in the same spot to measure. Any idea why the ported has the huge dip through most of its response or if it's fixable? I've moved the sub around some, flipped the port to the other side but nothing made an appreciable difference.


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post #2 of 9 Old 12-03-2019, 03:34 PM - Thread Starter
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Well, I'm mostly dumb, must have wired it backwards to the posts in the box I guess. Here it is with reversed polarity. Still a weirdly abrupt drop in response at 35Hz limiting the advantage of being ported, but it doesn't look horrible now at least.


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post #3 of 9 Old 12-03-2019, 03:35 PM
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Play with polarity and delay.

EDIT: you posted while I was composing. Now, I would try to pull everything down to match the low spot.
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post #4 of 9 Old 12-03-2019, 04:09 PM
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for the 2 subs involved here,

independently adjusted using mostly "delay" in terms of distance > many REW sweeps
so improvement is a possibility

YMMV
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post #5 of 9 Old 12-03-2019, 04:17 PM - Thread Starter
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Yeah, that is just one sub, so any delay shouldn't be an issue. I have a minidsp and XT32 to EQ/set delay with once I get the other ones done. I mainly just wanted to see if it was worth the ~$300 in supplies to make boxes that take up 3 times the room. I'm a little disappointed with the >10dB drop at 35Hz vs the sealed one, but I'll check some other spots in the room too.

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post #6 of 9 Old 12-03-2019, 05:17 PM
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That is likely the room and not the sub.

A full marty is flat from tuning on up, just like every other ported box.
Sealed only wins below 10hz.
From ~50hz up they will be nearly identical.
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post #7 of 9 Old 12-03-2019, 08:36 PM
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Quote:
Originally Posted by bradthebold88 View Post
Yeah, that is just one sub, so any delay shouldn't be an issue. I have a minidsp and XT32 to EQ/set delay with once I get the other ones done. I mainly just wanted to see if it was worth the ~$300 in supplies to make boxes that take up 3 times the room. I'm a little disappointed with the >10dB drop at 35Hz vs the sealed one, but I'll check some other spots in the room too.
You need drivers in exact same spot to compare above port contribution, so raise sealed up...
Its not a drop at >35hz, its a big boost <35 hz with the port contribution.
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post #8 of 9 Old 12-05-2019, 09:11 AM
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What size/dimensions of the room, where was the sub placed in the room, where is seating, and why have any confidence that the MLP in your room will mirror anechoic response? Show us a spatial average using the same mic positions that you used for xt32. That's the only viable way to reasonably analyze LF acoustic response when we are working with "small" room acoustic LF response.
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post #9 of 9 Old 12-05-2019, 09:31 AM
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Quote:
Originally Posted by Luke Kamp View Post
You need drivers in exact same spot to compare above port contribution, so raise sealed up...
Its not a drop at >35hz, its a big boost <35 hz with the port contribution.
I'm with Luke, you're getting a nice boost below 35 with the Marty, not a deficiency above 35 (assuming both measurements are at the same MV). That dip at 53 and peak at 70 are room related. If you EQ the Marty's low end the sweeps would be nearly identical … or you can use some of it in building a house curve … or, even better, move a sub around the room and find a second location that's strong from 35 to 65, add a second Marty there and use all those new-found dB's!

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