# lows cut off for some reason.



## Billy Mays (May 11, 2009)

some of the lower tones in the rap stuff i play gets cut off. it seems like i have nice level output until something low comes and all of a sudden it's like the amp is putting out half as much power. i have a JL 12w6 on a RF 500.2 at 4ohm. the amp is bridged and gain is about half way to full. 

the box is a prefab 2x12 but i only have one sub in. JL says to give it .9 cubes sealed. any recommendations?


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## Austin (Mar 12, 2009)

Sealed or ported? Sounds like your sealed. Normally sealed boxes roll off at low notes steeply. Going ported would solve this issue very quickly.


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## ehkewley (Jul 19, 2008)

Austin said:


> Sealed or ported? Sounds like your sealed. Normally sealed boxes roll off at low notes steeply. Going ported would solve this issue very quickly.


It sounds almost like a power issue. Does the amp have a protect light? are any of the amp lights dimming when it tries to get loud? Does this happen at any volume?


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## TREETOP (Feb 11, 2009)

Could be a leaky box, could be too small of a box, could very well be an electrical issue. Billy Mays, did you get the electrical issue in your other post figured out? I don't remember much except that you hadn't done the big 3 and your amp ground was loose enough that you could move it by hand..


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## Oliver (Jun 25, 2007)

If you are not using the full enclosure volume, try that 

If the sub is rolling off it will do a little better in more volume with the RF 500.2 at 4ohm.


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## Billy Mays (May 11, 2009)

TREETOP said:


> Could be a leaky box, could be too small of a box, could very well be an electrical issue. Billy Mays, did you get the electrical issue in your other post figured out? I don't remember much except that you hadn't done the big 3 and your amp ground was loose enough that you could move it by hand..


for the most part this is situated. it was the cap. now that i've wired around it the car isn't completely drained in the morning. it does need a battery but at the time of posting i wasn't having issues with lows due to the battery. i know this because i now am. volume in general isn't as loud as it should be at a given value on the head unit. seems like it's going almost completely off the alt now.

it's a prefab sealed box. i'm going for SQ more than SPL but would like to have some output. dynamics i guess it's called? i want loud stuff to be loud and tight/fast stuff to be tight and fast. it sounds great for the tight and fast stuff but when i play certain things i don't have any bass. i'd rather not get into any arguments for sealed vs ported for SQ. i don't think port noise will be heard over the rest of the music when the box is in the trunk of my coupe so i'm not worried about that. power handling is a concern though. this speaker only wants 600w. i don't want to have to cut that down if i go ported/larger box.


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## Oliver (Jun 25, 2007)

As the notes get lower they get longer [ read , U need some serious powa for them ].

Youe electrical system is coming up short


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## Billy Mays (May 11, 2009)

a$$hole said:


> As the notes get lower they get longer [ read , U need some serious powa for them ].
> 
> Youe electrical system is coming up short


so even with a bigger box or a ported box i'd need an HO alt?


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## Oliver (Jun 25, 2007)

The battery is in bad shape, replace it and you'll be okay for a while.

Your system design appeared to have what you needed in it.

It seems as if the battery was drug down repeatedly, thus causing the problem.

If you can swing an alternator that puts out more it'll help too !


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## Billy Mays (May 11, 2009)

it's kinda ironic that a guy called ******* is actually pretty nice.

the charging system is back to normal now. if i need more power and a quality box to push out the lows then i guess class D amps and a homebrew box are in the mix. 

about going ported. it seems that Fi Q will play very flat in a 2.2 ported box tuned to 25hz. do i want the sub to play flat or do i want to add some gain somewhere?


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## Oliver (Jun 25, 2007)

The ported will work very well for you.


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