i need some help setting my amp

[social atrophy 10+ year member]

Hello im runin 2 american bass 12's in a ported box 800 watts a piece.4 gauge wiring.now and a 2500 watt american bass mono block class D. i was told to only have my gain turned 3/4 of the way,as for my low pass, and subsonic what should i have them set at. i have all my deck setting on minus and my loud on my deck off

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[i2ain2thunder 10+ year member]

gain settings are for sending your subs the recommended RMS wattage (or user choice). You should be setting your gain according to your sub power handling. i'm sure if you use the search feature of this site and just type gain setting you'll find enough threads on how to do so. 20$ Digital Multimeter can get you close. If you want max power with as close to 0 distortion as possible an oscilloscope is necessary but they are very pricey. Most of us just use a DMM.

Subsonic filters remove any frequencies that may be too low for safe operation of your subwoofer. I personally don't care for them but most would set theirs around 20hz.

LPF Low Pass Filters allow any frequency below the setting threw. Depends on the octave of your slope and your blending needs with speakers, but generally speaking a setting anywhere between 70-90hz is pretty common as bass is a lot harder for your brain to tell direction at those lower frequencies. So it becomes less apparent to listeners that the bass is coming from the rear.

 

[quackhead 10+ year member]

HUH?..you set your gain to 3/4 turn clockwise??

do you understand the actual function of your amp gain?..it is to match HU output voltage to the amps' input voltage. When you set your gain, how much were you able to turn up the HU volume before you felt like it was loud enough, or too loud, even?..1/4?, 1/2?, 3/4?

I am not too familiar with AB subs, so I cannot guess which ones they are just by power rating. But the AB amps i have ran across do close enough to rated, and maybe more during peak transients. What ohm load are you running?..is the box specd to optimum dimensions?..a little smaller might handle more power, a little bigger might handle less power.. what is the tuning frequency of your box?..this should determine the subsonic filtering, due to uncontrolled cone travel below tuning frequency. This can destroy your subs from over excursion..personally, I use the -6 db mark on my setups. Most subsonic filters use a 24-36 db/octave cut-off slope.

As far as LP filtering, a good target is around 60-65 on subs and 80 on HP, to account for the 70 hz spike common in a lot of vehicles, but this also depends on your sub tuning frequency, midrange driver extension/placement. I prefer a 18 db/octave slope on subs at 63hz and 18 db/octave slope on mids at 80hz...but I usually play with that depending on my listening tastes...you prolly will too.

all of the above should be taken into consideration in some form or another when setting your gain(s) as well...u might use a DMM, but trust your ears, eyes and heart.

 

[social atrophy 10+ year member]

OK sorry i didnt inform much more info i have a ported box,they are the american bass DX 12's and the box is huge has 3 ported holes upfront i turned my gain to the middle not all the way up my lowpass is between 60 an 70 just cant get my subsongic down i have a cheap jvc deck maybe i need a better deck for a better output in voltage.Its weird cause when i had the subs hooked up in my girls car,i had a 1200 watt mono block planet audio an a kenwood deck an that **** thump so hard,the miles in the computer were shifting when it hits,now that its in my car it doesnt even compare to that.i wana feel the thump inside not outside my trunk raddles like **** an so does my license plate

 

---------- Post added at 12:25 PM ---------- Previous post was at 12:24 PM ----------

 

sorry i have the subs wired down to 2ohm load

 

[quackhead 10+ year member]

OK sorry i didnt inform much more info i have a ported box,they are the american bass DX 12's and the box is huge has 3 ported holes upfront i turned my gain to the middle not all the way up my lowpass is between 60 an 70 just cant get my subsongic down i have a cheap jvc deck maybe i need a better deck for a better output in voltage.Its weird cause when i had the subs hooked up in my girls car,i had a 1200 watt mono block planet audio an a kenwood deck an that **** thump so hard,the miles in the computer were shifting when it hits,now that its in my car it doesnt even compare to that.i wana feel the thump inside not outside my trunk raddles like **** an so does my license plate---------- Post added at 12:25 PM ---------- Previous post was at 12:24 PM ----------

 

sorry i have the subs wired down to 2ohm load

As far as amps and subs go, the subs are rated for 400 continuous/600 max. each. If you have either the black PH 2500, or the silver HD 2500..they are rated at around 1200 to 1250 watts at 1 ohm (2500 watts max rated)...if this is what you have, I would guess at roughly 600 to 900 watts available @ 2ohms...just a guess...you should be good there. The JVC, I know nothing about still, but it should be sending enough to satisfy the 6v - .2v inputs you require, depending on where you like to keep the volume set...when you open the trunk are you hearing any bottoming out ?...subs wired correctly, no phase issues?...on the subsonic cut-off, is it set at half or a little less? roughly @25 - 30hz..again, just guessing, not knowing your tuning frequency and all. Finally, what is the difference between your car and your girls'? you have them sealed in the trunk... with seat up?...facing back?..up? forward?...any holes in the deck for the sound to escape?