need help with amp gain/subs problem

[trunks9_us 10+ year member]

Ok i know that the gain is not a volume control button but i am a lil bit confused on how the gain is working. Ok so heres the thing i got 3 jbl gti's 12's there 700 rms each sub so thats a total of 2100 rms. They peak at 4000 watts each, so i am running a zapco 9.0 4ohm version and i am running these subs at a 4 ohm load. Well I have been told many times by my dealer and ppl on here the the gti's can hanle 1000 rms easy. Well my zapco 9.0 is rated at 2200 rms at 4ohms and its under rated so lets be on the big side and say its putting out 3000 rms. Ok so i had a dealer build me the correct box and its right i got the measurments checked out , there 38x12.5x16 outside measurement. With polyfill in the box.

http://manuals.harman.com/JBL/CAR/Boxes%20and%20Parameters/W12GTi_rev_f. pdf

http://manuals.harman.com/JBL/CAR/Owner%27s%20Manual/GTi%20MkII%20Sub%20 OM%2005.pdf

Its in a sealed box, & I am running 16 volts preamp from my hu to my amp which is what the amp can take. so it has clean power going to it and when it was working i had the gain set to 25, max is 30 which is what they told me not to go over. I am told by zapco.

http://www.zapco.com/prod/comp_prods/documents/TechnicalBulletinC2K9.04KW.pdf

my hu's max volume is 35 i have it at 29 before it starts clipping.

I usally keep volume at 28-29.

Read that techbulletin.

I also have a bass volume control knob to control bass.

Ok so now my question when i have it at 28 or 29 volume control i turn up the bass a lil bit then as i start to get to the middle on my knob its still hitting hard but about at 2/3 of the way i am going to open my trunk and the subs are hitting but its not sounding right. They sound totally different like bad sound but in the car with the trunk closed the sound fine. So what i am wandering is why is it sounding bad theres no pops or anything but u can just tell by how there sounding and how there sounding when the subs are hitting cause it sound nothing like it would if it was hitting at 1/2 or 1/3 the power. So any ideas on what to do? Plz read the zapco tech bulletin cause i would think turn the gain down but then i would never get my full rms wattage. so if u think its turn the gain down let me know but plz help me thx.

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[northjmp 10+ year member]

what i suggest doing is turn gain down, open trunk and listen. turn gain up with trunk open until subs sound bad and back off alittle.

 

[trunks9_us 10+ year member]

what i suggest doing is turn gain down, open trunk and listen. turn gain up with trunk open until subs sound bad and back off alittle.

I am thinking the same thing but by the way the tech sheet shows me on zapcos tech bulletin then i would not be getting my full rms which shouldnt i considering the subs should be able to handle it? Does this have anything to do with being in a sealed box?

 

[csnut18 10+ year member]

Why do you only have a 160 amp alt. If you were getting a ho one, why didnt you just go all the way and get one at least 200 amps?

 

[trunks9_us 10+ year member]

Why do you only have a 160 amp alt. If you were getting a ho one, why didnt you just go all the way and get one at least 200 amps?

b/c thats the biggest i could get. thats the biggest they offered.

 

[NewToTheGrounds 10+ year member]

you said that was a bass controll knob? and u set ur gains before adjusting your knob? you could be slamming your self bak into clipping if your adjusting it after you've already done ur gains...

 

[trunks9_us 10+ year member]

you said that was a bass controll knob? and u set ur gains before adjusting your knob? you could be slamming your self bak into clipping if your adjusting it after you've already done ur gains...

well like u said i adjust my gains first then i control the bass from the gain settings i made. I believe your right though that my gains are just to high.

 

[2002XLT 5,000+ posts]

buy a dmm??

and i dont see how your amp would be overrated by 800 watts, does that seem high to anyone else??

 

[trunks9_us 10+ year member]

buy a dmm??

and i dont see how your amp would be overrated by 800 watts, does that seem high to anyone else??

it was on the high side just to be saying that it was 3000 rms im not sure it really is i am just lets forsay it is.

Btw What is a dmm? some terms i am not familar with.

I am guessing digital multimeter and i alrdy have one of those.