1200W or 600W for 12" Brahama?

[nambo25 10+ year member]

How much of an audible difference would there be between running a 12" Brahma off a 600W amp and a 1200W amp (you can use the JBL 1200.1 vs. JBL 600.1 as an example)? The reason I ask is that I would like some decent SPL and with good SQ, but I don't want to have any electrical issues. BTW, my stock alternator is 100 amps and I also plan on running a 90-150W X 2 amp for my components. Thanks.

Click to read more...

 

[wesleysh 10+ year member]

With that alternator and a class D amp, you'll have no forseeable electrical issues with 1,200 watts. In theory you should receive a 3 dB increase between 600w and 1200w.

 

[nambo25 10+ year member]

I don't know how much of an audible difference 3dB is, I'm pretty new to car audio. I am currently running a 12" Brahma off a JBL 1200.1 and my interior lights are dimming, I'm not sure if this is something I should be concerned with. How much louder is 3dB?

 

[abercrombie2582 10+ year member]

3 db is the equivelent of another sub. Oh, and how bad are your lights dimming? If they aren't that bad, just get a capacitor for the amp and that should reduce the dimming. If it doesn't, id consider getting your alternator rewound for about 20 more amps!!

 

[wesleysh 10+ year member]

3 dB is supposed to be twice as loud, in theory. The average person can't tell a 1-2 dB difference, which is the real world expectation most of us can expect from doubling the power. I would say come down to 600w, and if you are lacking SPL, port it.

 

[nambo25 10+ year member]

Thanks for the input.

The dimming gets progressivley worse as I turn the volumn/and or bass up on the HU. I wouldn't say it's severe, but it is noticable. When the bass is turned all the way down on the HU, there's no dimming. I think I will keep the JBL 1200.1 and get a capacitor (although I've heard differing opinions about using caps). I'm kind of worried about having my alterator rewound, since it's a fairly new car. I don't want to introduce more electrical problems - is rewiring the alternator safe?

 

[wesleysh 10+ year member]

Capacitors work for people with small electrical "hiccups." If your lights only dim slightly and its annoying more than a real issue, go with a capacitor. If they dim majorly and the bass is even weak, it will actually hurt things more than help them.

I can't see it being too much of a problem with a 100 amp alternator and the JBL, but what do I know.//content.invisioncic.com/y282845/emoticons/banghead.gif.8606515f668c74f6de0281deb475b6fd.gif

 

[Mark_ab 5,000+ posts]

The JBL has a max current draw of 114A.

 

[MikeofTulsa Moderator]

getting the alt rewound will not hurt anything...good luck

 

[nambo25 10+ year member]

Thanks for the help guys. I changed my mind. I am going to have my JBL 1200.1 rewired to 4 ohms, ~600W, since I will not lose that much SPL going from 1200W to 600W. This way, my alternator is happy.

 

[blackgeltabs 5,000+ posts]

Getting the alternator rewound is a good idea. Also a deep cycle in the trunk wouldent hurt, itwould solve most of the electrical issues.

 

[Mark_ab 5,000+ posts]

Originally posted by nambo25 Thanks for the help guys. I changed my mind. I am going to have my JBL 1200.1 rewired to 4 ohms, ~600W, since I will not lose that much SPL going from 1200W to 600W. This way, my alternator is happy.

Good plan. I dont' know alot of people who need 1200W in a driver as capable as the Brahma for daily driving, that's just silly. //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif

 

[Llamas 10+ year member]

Originally posted by wesleysh 3 dB is supposed to be twice as loud, in theory. The average person can't tell a 1-2 dB difference, which is the real world expectation most of us can expect from doubling the power. I would say come down to 600w, and if you are lacking SPL, port it.

I think that's half right. I thought it was:

10db (1 bel) is a doubling in loudness (logarithmic)

2 x power = 3db increase in sound

The result being that after a certain point, ridiculous increases in amp power are needed to raise the volume appreciably. For instance, to double the max loudness from a 600W amp, you'd need a ~5000W amp.

Anyway, like wesleysh said, coming down to 600W would probably not be too noticable.

--Mike

 

[nismo 10+ year member]

caps...

once theyve discharged to keep your lights from dimming, they are nothing but another electrical load on your alt. if youre having problems with dimming, make sure that your battery-to-ground wire, alternator-to-ground, and alternator-to-battery wires have been upgraded to 1 size larger than your amp wire, b/c it must support the car also.

alternators...

theyre built to be able to dissipate a certain amount of heat, and when you rewind them, they will not last as long, as a result of higher heat. you gotta pay to play here, cuz nothing is free //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

as for you front amp, it should draw very little power, regardless of what its fused at. sub amps require a lot of current due to the fact that they must move large volumes of air, with very inefficient drivers, whereas the amp on highs needs to push the drivers very little to get a lot of output.

eric