first post....compatability question

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bigmike1
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first post....compatability question

Postby bigmike1 » Sun Jul 06, 2008 4:05 pm

i bought 2 xxx 12's and a rockford t2001bd. woofers wired at a single 2ohm load. the birth certificate on the amp says 2220rms@ 2ohms. and that obviously makes the required rms rating for the speakers. now the question is i've been hearing from certain individuals that this amp is not enough....is that so? why would that be?? it hasnt been taken out of the box yet so i can still return it, its not too late. help me out please.
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Postby nismo » Sun Jul 06, 2008 4:44 pm

It may not be enough to get 100% of the performance out of the woofers...BUT it should be enough to go deaf. The thing most people don't understand is that it's all about the install/design, and not as much about the equipment. 2kW is plenty of strain to put on your wallet and your ears. Even at that, you may want to seriously look into replacing the underhood wires (battery+ to alt+, battery- to chassis, and chassis to alt casing/engine block), as well as looking into a bigger alt/better battery. I HIGHLY suggest at least 1/0 from the battery to the amp, and from the amp to a goooooood solid ground in your car.

Do you have any idea what kind of box you're looking for? What kind of car do you drive, etc?

Eric
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Postby bigmike1 » Sun Jul 06, 2008 5:06 pm

thanks for the info. ive purchased the alternator (200a iraggi) but havent begun doing the things you mentioned, which was all already considered from the beginning. umm... pretty sure gonna be a sealed box due to space limitations since this will be going into ford ranger extra cab. plus im not too good a designing fancy ported boxes. any info or constructive criticism would be appreciated.
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Postby emperorjj1 » Mon Jul 07, 2008 6:04 am

not sure if u can get a 1 ohm load or how much u paid for the T2kw but i have a T3k for sale

oh is this the new XXX or old ones. I have 2 sealed 05 15s i ran off the T3k and it was awesome
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Postby 95Honda » Mon Jul 07, 2008 2:23 pm

The RMS power of the sub has absolutely nothing to do with how much power you may need, it all depends on your box. You could fry those subs with that amp, you could fry alot of subs with that amp. If you built an efficient enough box, that will be more thna enough power. If you put them in sealed boxes that are like 1/2 ft3 each, then that won't be enough power to get full output, but if they are in 4ft3 ported boxes each, they will get full output, see what I mean?

There is no such thing as "underpowering". This is a word/term/myth made up by speaker building/car audio arm-chair quaterbacks. If this were true, any time you listened to your system at any level except "Max" than you would be "underpowering"

The only reason manufacturers put RMS ratings on speakers is to cut down on the amount of fried voice coils they see...

The only specs that tell you how much power you need are Vas, Qts, Fs, Xmax and Sensitivity. Power handling doesn't fall into this equation anywhere.

If you need more in depth on this subject, say the word, you came to the right place....
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Postby KU40 » Mon Jul 07, 2008 4:44 pm

95Honda wrote:The RMS power of the sub has absolutely nothing to do with how much power you may need, it all depends on your box. You could fry those subs with that amp, you could fry alot of subs with that amp. If you built an efficient enough box, that will be more thna enough power. If you put them in sealed boxes that are like 1/2 ft3 each, then that won't be enough power to get full output, but if they are in 4ft3 ported boxes each, they will get full output, see what I mean?

There is no such thing as "underpowering". This is a word/term/myth made up by speaker building/car audio arm-chair quaterbacks. If this were true, any time you listened to your system at any level except "Max" than you would be "underpowering"

The only reason manufacturers put RMS ratings on speakers is to cut down on the amount of fried voice coils they see...

The only specs that tell you how much power you need are Vas, Qts, Fs, Xmax and Sensitivity. Power handling doesn't fall into this equation anywhere.

If you need more in depth on this subject, say the word, you came to the right place....


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.
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Postby nismo » Mon Jul 07, 2008 5:59 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.


You are correct. There is a possibility of destroying a driver by either mechanical or electrical means.

As far as underpowering, well I say it can happen...but not like you'd think. A lot of people think too small of an amp will kill a speaker. What often happens is that someone will buy an amp that isn't really enough to do what they want to do, so they crank the gains. They end up feeding square waves to their speakers, thus killing them. So technically NO you can't underpower a speaker and blow it, but its more a factor of abuse than anything else.

Here's a great example. A XXX powered off a 25 watt amp. You could crank it up until its a square wave (1 bajillion percent distortion) and it will never hurt it. Put a 1kW amp on it (its below RMS so technically could be considered underpowered by some) and crank the gains because its still not enough for somebody...it could blow the speaker--but its actually overpowering it through the square waves.

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Postby bigmike1 » Mon Jul 07, 2008 10:54 pm

i really appreciate the input! so sealed @ somewhere around 2.75-3.0 ft3 per woofer would be, ok??? oh and yes i would love more info as far as Vas, Qts, Fs, Xmax are concerned. i mean, i know the definiton of the terms but not how they apply to builiding a nice box. this is the first time im doing more than the basic install and you guys are really helping me out ALOT. thanks much.


95Honda wrote:The RMS power of the sub has absolutely nothing to do with how much power you may need, it all depends on your box. You could fry those subs with that amp, you could fry alot of subs with that amp. If you built an efficient enough box, that will be more thna enough power. If you put them in sealed boxes that are like 1/2 ft3 each, then that won't be enough power to get full output, but if they are in 4ft3 ported boxes each, they will get full output, see what I mean?

There is no such thing as "underpowering". This is a word/term/myth made up by speaker building/car audio arm-chair quaterbacks. If this were true, any time you listened to your system at any level except "Max" than you would be "underpowering"

The only reason manufacturers put RMS ratings on speakers is to cut down on the amount of fried voice coils they see...

The only specs that tell you how much power you need are Vas, Qts, Fs, Xmax and Sensitivity. Power handling doesn't fall into this equation anywhere.

If you need more in depth on this subject, say the word, you came to the right place....
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bigmike1
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Postby bigmike1 » Mon Jul 07, 2008 10:58 pm

emperorjj1 wrote:not sure if u can get a 1 ohm load or how much u paid for the T2kw but i have a T3k for sale

oh is this the new XXX or old ones. I have 2 sealed 05 15s i ran off the T3k and it was awesome



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.
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Postby emperorjj1 » Tue Jul 08, 2008 2:35 am

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.

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