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Discussion Starter #1

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:

Introduction:
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:

Pros:
+ 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
Cons:
- 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:

WORK IN PROGRESS


WORK IN PROGRESS


WORK IN PROGRESS


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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1st impressions (glue barely dried up, lol)!

Transformers beginning/base attack:
Right after voice in the movie beginning says '..but we we're already too late!" and helicopter shows up --> :hsd:! :devil: Really really nice semi-deep and floor shaking bass which I could not achieve with Creative Sound Solutions SD12 @ 120 liter box @ 18Hz tuning. Bass with this closed shiva box is really tight and fast. Continuing to base attack impressions we're pretty much the same. Bass sounds deep and controlled and truly shakes the room.

Transformers base attack survivors battle this scorpion type robot in the desert:
All the missiles fired by the decepticon transformer really makes the impact feel real. My ears were little numb because bass levels climbed as high as 109dB (+/- 3dB), but still Shivas we're completely in controll of the bass. I was impressed how controlled and detailed the bass was.

105 sabot rounds and the THUDS on the ground made Shivas work about 1cm P-P excursion which is even more impressive considering SPL was way over 100dB there. Those thuds must be at 30-40Hz range.

These drivers are beasts even in very small cabinet like mine! :unbelievable:

Next up is doing some measurements and maybe finally getting that BFD or anti-mode. I know there are few mountains in the Frequency Response without measuring it with REW! :R
 

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1st impressions (glue barely dried up, lol)!

Transformers beginning/base attack:
Right after voice in the movie beginning says '..but we we're already too late!" and helicopter shows up --> :hsd:! :devil: Really really nice semi-deep and floor shaking bass which I could not achieve with Creative Sound Solutions SD12 @ 120 liter box @ 18Hz tuning. Bass with this closed shiva box is really tight and fast. Continuing to base attack impressions we're pretty much the same. Bass sounds deep and controlled and truly shakes the room.

Transformers base attack survivors battle this scorpion type robot in the desert:
All the missiles fired by the decepticon transformer really makes the impact feel real. My ears were little numb because bass levels climbed as high as 109dB (+/- 3dB), but still Shivas we're completely in controll of the bass. I was impressed how controlled and detailed the bass was.

105 sabot rounds and the THUDS on the ground made Shivas work about 1cm P-P excursion which is even more impressive considering SPL was way over 100dB there. Those thuds must be at 30-40Hz range.

These drivers are beasts even in very small cabinet like mine! :unbelievable:

Next up is doing some measurements and maybe finally getting that BFD or anti-mode. I know there are few mountains in the Frequency Response without measuring it with REW! :R
Awesome job. I love the overall finish!

Keep us up to date with final measurements.

Kevin Haskins
Exodus Audio
 

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Discussion Starter #6 (Edited)
Thanks Kevin!

Did a little testing with music of Infected Mushroom -electronic band. Songs were Spaniard, Dancing with Kadaffi and never never land. Especially Spaniard which has bass drum 16Hz and up. It did a great workout for Shivas and I have to say... :scared: My friend guessed there was 115dB - 120dB in the air and he has experience of that with SDX15 LLT monster. :R I can't say for sure but as far as I could tell there was no problems with Shivas. Phenomenal subs I have to say.

I can't even imagine how some your LLT/IB monsters will sound like, but this is almost too much for me! :D When I can feel the bass in my jeans and in my chest, I call it quits! :dizzy:

EDIT: I used this SPL meter for measurements. I just could not get it to work with REW so here are 'manual' measurements by using sine waves. SPL meter is IEC 651/type 2 and ANSI S1.4/type 2 compatible which means it is accurate 30Hz - 8kHz. I don't know if <30Hz meas is accurate?! EDIT: Measurement done from listening position.

 

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Looks good. I like the veneer! I have been thinking about doing a dual Shiva-X myself (probably a pair of them). I know these are considered to be the "little" woofers by Exodus but they are very impressive. Also, based on my calculations, together two of these move more air than most 15" drivers so that doesn't sound so little to me.

I would like to see some REW measurements. What kind of problem did you have?

Mike
 

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Discussion Starter #11
I use Unibox to model subs and my box volume (115 liters) shows these Qtc figures:
  • No fill: 0.754 - Acoustic box volume seen by driver 116 liters
  • Minimal fill: 0.752 - Acoustic box volume seen by driver 117 liters
  • Walls covered: 0.723 - Acoustic box volume seen by driver 122 liters
  • Heavy fill: 0.643 - Acoustic box volume seen by driver 139 liters
I used about 1.5kg (~3pounds) of fill and I call that heavy! :)

This is WinISD model for both my box and atc .707 box.



I would like to see some REW measurements. What kind of problem did you have?

Mike
I'll get back to this once I get proper cables.
 

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Discussion Starter #12
Ok I did the magic with REW. Again I am using a SPL meter which is IEC 651/type 2 and ANSI S1.4/type 2 compliant so I don't know if <30Hz is accurate. But here they are all with 1/6 octave smoothing.

 

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Not bad at all. Assuming the graph is accurate (and I have no reason to doubt that it is) you are getting some nice <20Hz action there. A very capable sub indeed. Congratz!

For some reason I was thinking you built two of these. Did you build one or two?

Mike
 

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Discussion Starter #14 (Edited)
Not bad at all. Assuming the graph is accurate (and I have no reason to doubt that it is) you are getting some nice <20Hz action there. A very capable sub indeed. Congratz!

For some reason I was thinking you built two of these. Did you build one or two?

Mike
I have one 4,06cu^3 sonotube which has two Shiva-X drivers. One in both ends of the tube. And it really shakes the room which is pretty remarkable considering the size of the sub. (You know, it is small...)

EDIT:

Here you see both drivers:


There you see one driver:


And there you see another.
 

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OK. Yeah, I knew it was a dual Shiva-X design. This is a nice sub. You don't see too many sealed sonotube subs. I think it is a very cool idea. Even though the Shivas are considered the little guys in the Exodus family of drivers, this is probably more output than most people need and it should be nice and tight sounding bass too. Great sub!

Mike
 

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Discussion Starter #17
Is it me or is this sub a bit *hot* compared to the mains?
Ye, that is how it seems, but REW sub cal signal shows 75dB on the SPL meter and so does REW speaker cal signal with the mains. Funny how the level seems to rise so much in full range measurement compared to sub only. I blame the calibration procedure.

Although mains have that nice 'hole' between in about 150Hz and it rises a bit after 200Hz again. Should have taken the full meas up to 8kHz to see the median.
 

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very nice build this is something i might be interested in building myself. would you mind telling what diameter and length tube you are using and if the drivers are wired out of phase? thank you
 

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Discussion Starter #19
very nice build this is something i might be interested in building myself. would you mind telling what diameter and length tube you are using and if the drivers are wired out of phase? thank you
Tube lenght is 1015mm. Tube inside diameter is 400mm. Outside diameter 414mm.

Drivers are not out of phase because there would be no sound at all. Drivers must create pressure inside the box to create pressure outside the box.
 
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