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Less cone = more bass ? Possible?

Old 05-31-2011, 10:33 AM
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Less cone = more bass ? Possible?

Here's a few pics of the setup as it was at the last comp. With 2k we managed to burp a 140.7db in qualifying. Not really the 143+db we had hoped for so we could 139.9 bassrace.
The subs we're very tight, only got reconed the day before, we also had no time to find a TL and our peak frequency. So I'm guessing there should be a db or 2 still in the box/3 sub setup.

But, back on topic.
On the advice of another competitor, when we got home, we unhooked the middle sub, rewiring at 1 ohm instead of .67
Left the sub in though, unhooked, and played some music. We didn't have a TL but we were both sure it was louder!! With one unhooked sub!!

The box is about 5 cubes after displacments tuned to 34 hz ( but probably wrong now that I understand boxes a little better)
Also I had forgotten, but the builder recommended 2.5 cubes per sub.

So could it have actually been louder on the TL(instead of our ears) with only 2 subs instead of 3, simply due to the efficiency of the box/subs together?

I don't want to call the box a FAIL yet, whats going on?
Attached Thumbnails Less cone = more bass ? Possible?-installed-002.jpg   Less cone = more bass ? Possible?-installed-004.jpg   Less cone = more bass ? Possible?-installed-006.jpg   Less cone = more bass ? Possible?-installed-008.jpg  

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Old 05-31-2011, 11:33 AM
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2k couldn't yield a 39.9 bass race? Something is wrong there.

Maybe the 3rd sub was creating a phase issue? In any case 2k on 3 12s(?), a 39.9 bass race should have been easy.
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Old 05-31-2011, 12:54 PM
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Originally Posted by fresh1 View Post
2k couldn't yield a 39.9 bass race? Something is wrong there.

Maybe the 3rd sub was creating a phase issue? In any case 2k on 3 12s(?), a 39.9 bass race should have been easy.
Yeah, 3 dvc 12s but I was real glad I foresaw not hitting 143, and signed up for 129..9 instead. small mercy

I'll need to do some reading about phase issues , then I'll comment on your idea. I have no clue about phase really thanks though
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Old 05-31-2011, 05:00 PM
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Left the sub in though, unhooked, and played some music. We didn't have a TL but we were both sure it was louder!! With one unhooked sub!
Doesn't that make it a passive radiator?

Shouldn't the amp be making more power at .67 ohm and therefore be louder?

Why phasing if they're all on the same dimension? Does wiring at .67 ohm create uneven movement?
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Old 05-31-2011, 05:37 PM
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Originally Posted by Lord Huggington View Post
Doesn't that make it a passive radiator?

Shouldn't the amp be making more power at .67 ohm and therefore be louder?
yes.
yes.

The weren't hooked up backwards fresh, if that what you were getting at, that seems to be all I understand about phase and subs

You see why I'm confused.

We just finished sealing up the middle sub cutout. Sounds better and a lil louder than the PR setup..lol
The amp will run cooler at 1 anyhow.
Maybe we need 2 boxes, daily and a SPL oriented one. Would solve some of the problem..maybe
Better ask someone that know his stuff to design me a box or 2
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Old 05-31-2011, 06:02 PM
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Phase is basically speakers moving in opposite directions. Easy way to test it is to wire them up the way you had them at the show, then take your + and - speaker leads going into the amp and touch them to a drill battery, they should move in or out as far as they can and stay there. Then just look to see if they're all in or all out. I've wired two dvc's to 4 ohms not paying attention to what I was doing and had them wired out of phase. Big PIA to take them out and fix it (even worse when you do the same thing over again and end up going through the process twice...don't install when its dark and you're drunk. Better yet, just don't drink)

But yeah as long as they're wired correctly the 3 should be louder.

My other guess would be that somehow your box rise is higher with 3 subs than with 2. Don't ask me how its possible, but I take nothing out of the equation when it comes to SPL. Time and time again I've found myself having no clue how things are working to do what they do in this game. Case in point, a 600 watt Sony amp producing more spl than a 2k watt amp
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Old 05-31-2011, 06:12 PM
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what subs are they?
5cubes sounds a little small for 3 12's.
I had a single 12 doing 144 tuned @ 34hz with 1500w
having unhooked one sub, you effectively gave the other two subs more air to play in, possibly allowing them to play louder.
there are SO many variables its hard to even guess over the net.
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Old 05-31-2011, 07:04 PM
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Easy way to test it is to wire them up the way you had them at the show, then take your + and - speaker leads going into the amp and touch them to a drill battery, they should move in or out as far as they can and stay there.
Right on, we'll try that sometime soon. The only drill battery I have is 18v, not 12v though ..

Case in point, a 600 watt Sony amp producing more spl than a 2k watt amp
I'm soo embarressed...lol...but that was great to see!!

what subs are they?
5cubes sounds a little small for 3 12's.
I had a single 12 doing 144 tuned @ 34hz with 1500w
having unhooked one sub, you effectively gave the other two subs more air to play in, possibly allowing them to play louder.
there are SO many variables its hard to even guess over the net.
TC9 motors and custom soft parts.. kinda a TC Sounds LMS-R 12", at least similar, but with 12 spoke baskets. Was told power handling was about 1500 wrms 3000 max .
Should be in more cubes probably, I took too many cubes out adding the sonotube curve inside, the box is over 7 cubes before displacements!! And like Yuli and others pointed out during construction.. dang hard to swap out ports

Could maybe cut out that curve , gain the cubes back and change ports easier too.. a start anyhow, don't think it does much

Gotta check the phase SOON

the box build - http://www.canadiancaraudio.com/showthread.php?t=247971

Last edited by SOULMUSIC; 05-31-2011 at 07:32 PM.
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Old 06-03-2011, 06:40 PM
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you can bassrace a 139.9 with $500 worth of equipment as long as you do everything yourself...
3 - 8" subs and a really old 2x150 amp! ( 600 watts RMS bridged , powered by only 4 awg from stock battery)
sometimes I would even overshoot 140 by accident
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Old 06-04-2011, 04:44 AM
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Tell me you did that in an extended minivan MTA and I'll just have to quite now..
Checked the phase, all good unfortunately, so its not that. I was kinda hoping really.
We're hopefully getting the box reworked this weekend, taking out the curve and raising the tuning a bit, try to tweak the amp some more etc.
If that doesn't do it, we'll try the box in a different configuration as suggested by a few guys. After that I don't know, just gonna cross my fingers and hope.
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