first post....compatability question

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bigmike1
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Postby bigmike1 » Tue Jul 08, 2008 3:32 am

emperorjj1 wrote:esh they are even more power hungry. But all these guys are correct you cant really underpower a speaker but if the new XXX is like the MX (which it should be) it takes a bit to get it moving. I havent had any personal experiance with the new xxx's myself since the only one we've done at the shop happened on my day off. But ive dealt with a few MXs.

the issue i see you running into is going to be with the box. Sealed is allright but like nisimo said ported is going to stand out more especially when the speakers can handle more power wise. BUT ported boxes really need to be designed correctly to work right. If you got some crazy nonsense tuned to 60hz+ and leaking air its going to flop on its face.

Also when doing the box your going to want to be sure and do plenty of braces and probably double up on the face. Most of the boxes ive seen returned with the big speakers we sell (MX, SX, MT) all just have the single baffle. I dont think ive seen anyone with a dual baffle box come back with issues reguarding the box itself.



cool, thanks. ive tried my hand at designing a ported box but, im worried if its gonna come out right. im a mechanic by trade so i HAVE TO build it myself. but also ive had a few concerns. first off would be would the box need to have ports on either side of it?? essentialy like this: http://www.diamondaudio.com/PDF/current/WiringEnclosures/Dual12VentedEnclosure.pdf (didnt know any other place to reference)

or is a single port ok> the other problem is IF i can get that size box in my vehicle, is having the ports that close to the ears ok?? i know of rounding over the edges of the port w/ a router to reduce port noise, but we are talking like a foot away.

again you guys rock, thanks for helping me design a great system!!
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bigmike1
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Postby bigmike1 » Tue Jul 08, 2008 3:35 am

bigmike1 wrote:much appreciate the offer. for the moment im going to pass and see how this develops, but thanks. they are the newest xxx's btw.



oh and p.s. what was the specs on that box??
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Postby KU40 » Tue Jul 08, 2008 9:10 am

Well having the ports close to your ears is a personal thing. But just realize that the SPL right by the port is higher than a few feet away. People that hit 150 db with the mic at the dash usually hit over 160 db at the port opening if they do port wars.

as for the ported box, no you don't have to use two ports. One is just fine.

Where did you find those size specs for a sealed box? RE's site recommends around 1 cube per woofer sealed for 12s. Obviously like 95Honda was talking about, size of the box is power dependent, so since you have "only" 1000 watts going to those speakers, a larger box may be required to get to their potential. However, 3 feet may be a bit large. You may want to download some enclosure software, like winISD (I use the alpha version) to get a feel for how the woofers react to different enclosure sizes. You can also model up a ported box. That program can also allow you to plug in the power you are going to use so you can tell how the woofer will perform in a given box size.
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Postby 95Honda » Tue Jul 08, 2008 3:01 pm

KU40 wrote:Couldn't there be a situation in your example where 1/2 cubic foot may not be enough to mechanically limit the speaker, but the thermal limit is reached and the voice coil is fried? Maybe I'm not reading your example correctly. Are you just talking about mechanical maximization in that example? If so then I understand. But I would think that thermal power handling would be useful for the overall application.



Yep, I'm talking mechanical here, AKA how much power to get the sucker to move all way...

I'm trying to point out that if you are smart about the box, you can get full potential out of your sub without walking the thermal power handling tight-rope... So to say..
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Postby nismo » Tue Jul 08, 2008 4:51 pm

Yes, and the other mis-nomer is that a smaller box has 'tighter' bass than a larger one...but this is the opposite of the truth. If you use a smaller box, you get a peakier response and you need more EQ to fix it.

So to sum it up, you have to use more power in a small box because of efficiency, and you have to use more power (EQ) to get the lows...neither are good for a coil.

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Postby KU40 » Tue Jul 08, 2008 10:30 pm

95Honda wrote:Yep, I'm talking mechanical here, AKA how much power to get the sucker to move all way...

I'm trying to point out that if you are smart about the box, you can get full potential out of your sub without walking the thermal power handling tight-rope... So to say..


gotcha. I think I'd rather walk the mechanical tight rope rather than the thermal one. At least with mechanical you can usually hear it being stressed out, whereas with thermal, unless it's in the cab close to you so you can smell something burning, you have no idea.
-Nick aka NS1 aka mopey aka speedbump

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Crossfire CFQ5.2

JL Audio XR 650csi components, Planet Audio TT2300

Crossfire VR404 on factory rear 6x8's until I get them upgraded

SI 15D2 + 3.8 @ 30 hz + Crossfire BMF 1000D = :)
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Postby emperorjj1 » Wed Jul 09, 2008 2:03 am

its a littler harder to describe mechanical movement over thermal power since they are both codependent. the XXX will usuallyneed the full power to fully move mechanically. And if youve never seen one move your in for a surprise. Ive never done this in a ported box but a test to see full movement is a 60-0 sweep on low power in a sealed box no subsonic. You can easily max subs out mechaniclly very little power at those subsonic freqs but its not really a good idea in a ported box
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Postby emperorjj1 » Wed Jul 09, 2008 2:06 am

bigmike1 wrote:oh and p.s. what was the specs on that box??


my box?
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bigmike1
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Postby bigmike1 » Wed Jul 09, 2008 3:34 am

[quote="KU40"]

Where did you find those size specs for a sealed box?



i was going through some reviews on the subs before i bought them and i came across one from car stereo mag and it said in there, this is a quote:

"recommendations: a compact size of 0.85ft3 and an optimum size of 1.1ft3. Because of the sheer bulk of this subwoofer, I was surprised by just how small these two recommended enclosures were. As is my custom, I gave the manufacturer a call to get their absolute best enclosure recommen-
dation for sound quality. When Larry Ratcliff of RE Audio gave me the specs, I
was taken aback, shocked even, when the answer came back almost three times
larger then the recommended size at 2.843ft3! That’s one big box, but it is more
in line with what I would expect."

i just figured that was fairly reliable info, or is it? so i was just taking that appx times 2. no good?
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bigmike1
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Postby bigmike1 » Wed Jul 09, 2008 3:42 am

emperorjj1 wrote:my box?



yah, just curious.

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