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Aaand yet another Shiva-X thread... DUAL!

11412 Views 30 Replies 9 Participants Last post by  Jugix

Hello all! This thread is to show my limited DIY skills to all you out there. I have had project ongoing for whole springtime here in Finland meaning 1.1.2009 all the way to date. Project is almost done so pretty much all the flaws you see in my design cannot be corrected! :bigsmile: I have quite a patch of pictures and I will upload all of them soon but here is the intro. Hope you enjoy! :neener:

Enclosure: 115 liter sealed sonotube (4,06 ft^3)
Drivers: Two Exodus Audio Shiva-X both in the same sonotube opposing ends.
Amplification: The T.AMP TA2400 [~1x2000W continous 8ohm)

Pre-project thoughts:
Why sealed. Because I have had many different flavours of vented subs last one being CSS SD12 @ 120 liter tuned to 18Hz. SD12 was excellent at movies but it lacked the musicality somewhat... So therefore I took the route to build sealed for these reasons:

+ Group delay very low across the whole frequency range
+ Phase response more even
+ Ultra low frequencies do not *CRITICAL HIT* the sub so badly compared to vented --> no HPF to add delays of any kind.
+ Frequence response rolloff better suited for massive room gains at lower end.
+ Subs 1m apart from each other vertically. Might do something to those bad standing waves which are room generated between floor and ceiling. Dunno, just a theory....
+ I wanted to build something! :R
- SPL lower to vented --> dual sub needed to achieve same SPL (and more) as my former CSS SD12 vented.

Unibox simulations:

As you can see from the pictures this enclosure is very tight fit for two Shiva-X. Can not go much smaller than this, eh! :whistling: Power requirements are ofc higher in smaller box but I can afford it. Here are couple more pictures but remember WORK IN PROGRESS! :foottap:




Feet are *NOT* going to end up looking like that! I am going to cut them so only 6cm chrome tube is left. I just quickly threw the tube on footplate and chromefeet and it barely stood there while I took the pics! :nerd:

So, I really appreciate all the input you give. I try to update this thread as soon as I have time. Pretty wild week ahead of me but hang in there people.

-- Jukka
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Hi Mika it's not tuned, it's a sealed enclosure.
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.
+ 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 ?
Jugix: Did u ever think to go with 2 separate single driver enclosures ?
Yeah, I thought about it, but wife-factor made me think other way... :bigsmile: Anyways I am happy of the result.
You have good response there.
Did you put a grill over the top driver?
You have good response there.
Did you put a grill over the top driver?
Grill is under construction. I finish it in summertime when I have more time available.
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
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. :)
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.. :)


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



Measurements taken from listening position. Sub 2.6 meters away.
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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?

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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.

Text White Line Plot Pattern
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