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Discussion Starter #22
It's tuned to 38Hz, and ur in-room response is flat to 18 ?? :scratch:
It is sealed enclosure and we are not talking of the same 'tuning' as in vented. Sealed ofc has tuning freq which is comparable to volume and in this case it is 38Hz.

This means FR begins to drop ~12dB/oct after 38Hz but my lowest room generated resonance is in ~50Hz, and below that FR gains 12dB/oct. This phenomenom makes my sub FR go flat to 17Hz.
 

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+ Frequence response rolloff better suited for massive room gains at lower end.
After re-reading, this explains it better for me, I wouldn't be getting that sort of room gain at all :cunning:

Jugix: Did u ever think to go with 2 separate single driver enclosures ?
 

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how big was the room you put these in? i have a infinity simple build at 4ft3 tuned to 20hz and it does a great job but i think the room is a little large for it and i would need another one but wife says hell no to another large box so i thought maybe i could get away with a tube or two of the same size because it doesnt appear to be as large. (illusion lol) my room size is 18 X 35 its a open lay out with family room eating area and kitchen. i dont know what kind of room response i would get to help me achieve down to 20hz for some ht use if i would need one or two id be powering it with a day hspa1000r rack amp witch is rated at 1000w into 4 ohms i know the shiva can be wired in many different was to achieve a 4ohm load thats why i was thinking of build 2
 

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Discussion Starter #28
My living room is about 6meter x 4.5meter x 2.7meter (LxWxH). Also kitchen/eating and hall area are pretty much the same space because living-room opens up to them so whole area is about 55 square meters. I'd say my sub is in very open space. This is all very subjective but when Shivas approach half way of linear excursion in movie explosions I have to tone the volume down. It is just not funny anymore.. SPL meter shows 110dB about then. :)
 

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Discussion Starter #29 (Edited)
Watched The Incredibles. I took my decibel meter off the case in a section where Mr. Incredible fights 1st time this evil robot thingy in the tropical island. Measured 111dB at listeling position. Shivas did not even sweat.. :)

EDIT:

Measured MAX SPL when rocket takes off at the first time.



SLOW


FAST


Measurements taken from listening position. Sub 2.6 meters away.
 

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Discussion Starter #30
Hello again.

I suddenly noticed I can make waterfalls from my FR measurement. Can someone decipher what these waterfalls mean? :) Explanations in Frequence response image for each colour.









Any advices how to correct possible flaws? Anti-mode? Feedback destroyer? Phase knob?

Thanks!
 

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Discussion Starter #31
Finally got time to play with BFD. Here are initial results. I am still trying out different solutions but here is one graph using 4 filters on BFD. Notice 8dB level rise from 80Hz towards low-end. Full-range average is at 85dB.

I used Behringer ECM8000 calibrated by cross spectrum labs. Correct values from 5Hz - 20kHz.

graph.jpg
 
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