300w too much?

[Neb1373]

Right now I have a 12" jl sub with an underpowered 150w amp. I'm not running a cap right now because I didn't think I would need one with this low wattage. If I ever have my dome lights on they dim like crazy when the bass hits and also do the headlights. Right now I am debating adding another identical amp and sub but don't want to totally kill my jeep with double the wattage. What is everyone running? Cap or not? And do you have any dimming at all? Or do I have a problem? I am also running I believe 8ga wire. Which should be good...


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[JLRockies]

300 Watts at 12.5V = 24 Amps. This assumes low crest factor music run to high levels of clipping.

If you're having trouble with half this power, something is very wrong. Either your batt sux, your amp "gain" is improperly set and/or you're using excessive equalization.

A capacitor us always a bad idea and if you're amp need one to work properly, you're better off buying a properly built amp and a good installation.

I have a 500/5 in my system since 2007 and have no problems.

 

[Neb1373]

Oh yeah. It is an mtx rt-202 with the gain maxed out. Maybe this will be an excuse to buy a more powerful amp and bridge to 2ohm.


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[KJDevildog]

There is no reason a 150w amp should draw so much current that it causes your lights to dim. It sounds like you have electrical issues, or your sound system has some bad wiring somewhere.

I ran 1400w RMS in my last jeep with a 90 amp alternator and I barely had dimming.

Also, your gain is NOT a volume control and should NOT be maxed out. There is a method to setting your gain.

The easy way to do it is to turn your head unit volume to 75% and then turn the amp gain up slowly until you hear a little distortion, then back it off just a bit.

 

[Neb1373]

Well gain is similar to a volume, the gain knob adjusts the current being allowed to come in to the amp thru the RCA cables. With my small underpowered amp I have the gain at max allowing for full current and max "volume" of the sub. You tell me to set my head unit at 75% then adjust the gain on the amp until I hear distortion and back off? I have absolutely no distortion at all. I am wondering if maybe just a different amp would help me and maybe not draw as much power. The amp is about 8 yrs old or so. I will check my wiring tomorrow and make sure the grounds are all clean and snug, along with the power. And I like you could not see how I am getting any dimming also.


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[JLRockies]

Most people couldn't hear distortion with music and assume distortion is music if their exposure to music is anything recorded after 2000 and downloaded or ripped.
Even golden-eared audiophiles cannot detect distortion levels as high as 20% in the sub range. Since most modern music is recorded with such low crest factor, it renders the decades old "listen for distortion" technique moot.

There's a flash video on proper "gain" setting posted at jlaudio.com

BTW, in improperly set-up larger amp will only make the problems worse.

 

[Neb1373]

BTW, in improperly set-up larger amp will only make the problems worse.

should I maybe get a larger amp? Hook it up to the 2 subs, and maybe have my local sound shop "tune" it? Or set it up properly?


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[Neb1373]

Well, I have checked all of my connections and the only thing I can think of is maybe my battery is too small??? Could someone check and see if this is right? I ran a search on here and came back with nothing but when I searched for batteries on google I was coming up with higher cca....

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[Neb1373]

800cca/1000ca seems to be the going rate. I think my dealer slapped in a 4 cylinder battery for me. Looks like I gotta go battery shopping before I go amp/sub shopping...


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