Subs lacking oomph in pickup. Please evaluate what I'm doing wrong.

[hleonard16]

Howdy,

New to the forum but am not new to forums. I apologize if I'm a n00b in the forum but I know my way around car audio fairly well and am looking for your insight to my issues. Yes I've searched the forums and scoured Google (not sure if "searching" before posting is a big issue here").

I own a 2012 F250 crew cab. JL audio C3 components, JL audio 5 channel amp running those, but that's not the problem. This amp is fed with its own 4 gauge line, separate from the sub amp.

Two Sundown Audio SD3 series 10" woofers in a 1 CF stuffed box behind the back seat (no room for anything). These are being driven with a Rockford Fosgate 1200 watt mono amp, 1 ohm stable and the subs are wired down to 1 ohm. It's something like 200 watts over what they're rated for but it shouldn't be an issue. I wanna say 10 gauge OFC wiring runs from the amp to the subs, and the amp is fed by a 4 gauge line with a hundred amp or so fuse. Dedicated line, grounded at a bolt in the body in the back (literally the only ground point I can find.) Settings are:
Gain 3.5/10
LPF ~80 HZ
Punch EQ (bass boost) Off
4 volt pre-out signal coming from Pioneer double dinn HU

The subs cut out at volumes above 1/2, like the amp is going into protect mode. Just when I feel like there right before they start slamming like they should, they cut out. More so on lengthy bass notes and such. I just do not understand. I ran a dedicated 12v line to the amp to see if that fixed the problem, and no dice, but did make them play clearer. It's like the amp is going into protect mode, but for reasons I do not know why. It's really starting to make me mad. I bought these subs because I figured it would be as close to slamming as I could get in a pickup, but have no dice. It's not a low voltage problem I don't think; alternator puts out a steady 14v and dips to 13.8 at the lowest when they hit. 200 amp alt.

Any clues..suggestions...insight?

I had two JL Audio W3 12s in my tahoe at 800w on the same rockford amp (2 ohm) in a ported larger inclosure and those SLAMMED. And sounded clean and detailed as all get out. I know that's not possible in a super duty without real custom setups, but I want to maximize what I have. I know it won't match my W3s, but I also know they should get after it. I mean, they hardly keep up with my JL C3s in the doors. Definitely get drowned out after about 3/4 volume.

Edit. Just went out and regrounded, sanding down the paint and anchoring to the body really good. While it does sound better, it is still cutting out, the amp turns red for a split second and contenues on.

I know in my Tahoe I had the subs in the cargo area basically staged to "bounce" the sound off the tail end doors, and it sounded loud as hell and clean up in the drivers seat. I had them mounted inverted to free up just a little more box space and I swear they sounded cleaner and a hair louder being inverted vs. traditional driver mounted in box. It was a clean setup and I miss it every day.

Where I'm going is I know I cannot image the sound in my pickup for my subs like I could in the tahoe due to space. So, I guess I'm trying to work around that.

[Ron36]

The only thing I notice is that box is alittle big should be around 1cube for both subs u got almost double that. Even with sub displacement still to big. U could fit 3 of those subs in that box

[hleonard16]

The only thing I notice is that box is alittle big should be around 1cube for both subs u got almost double that. Even with sub displacement still to big. U could fit 3 of those subs in that box

I apologize; it is a 1 CF box. Should be dead on for the subs. Maybe even a little small

[Bayuk89]

Double check ALL your power and grounds, make sure all connections are clean and tight and any paint is removed on the grounds

Sound like went you get 1/2 volume ur amp pulls more current and it cuts out. Sounds to me like a power or ground issue. Disconnect your speaker wire from the amp and double check your ohm load too. Some amps will cut out if your wired too low. May also need to check ur RCA cables, might be loosing signal for some reason... it could be a few things.

[hleonard16]

Double check ALL your power and grounds, make sure all connections are clean and tight and any paint is removed on the grounds

Sound like went you get 1/2 volume ur amp pulls more current and it cuts out. Sounds to me like a power or ground issue. Disconnect your speaker wire from the amp and double check your ohm load too. Some amps will cut out if your wired too low. May also need to check ur RCA cables, might be loosing signal for some reason... it could be a few things.

Yeah I've changed out the RCA's, know there is a good connection at the batteries and at the amps, know that the grounds are fairly good now, and I know for a fact that the wires at the sub terminals and box terminals are not touching because I taped them off to see if that was the issue. (spring loaded terminals). How would I go about checking the resistance at the amp without a SMD-1 or fancy meter?

[frogcase2002]

Can check It with a cheap dmm

[Triticum Agricolam]

Can check It with a cheap dmm

Yes

[ShadeTreeMechanic]

Make sure you have 4 ohm coils. If you have 2 ohm coils and all in parallel would be .5 ohms.

[diegoclass2010]

My buddy Had a Rockford fosgate that did the same thing then it blew, his install was good since i did it, but the amp was bought used,swamped out for a new Crossfire audio amp, hasn't had a problem since.

[hleonard16]

Make sure you have 4 ohm coils. If you have 2 ohm coils and all in parallel would be .5 ohms.

They are dual 4 ohm coils per woofer, and effectively wired down to 1 ohm.

My buddy Had a Rockford fosgate that did the same thing then it blew, his install was good since i did it, but the amp was bought used,swamped out for a new Crossfire audio amp, hasn't had a problem since.

I have a feeling the amp may be the culprit, but don't really want to shell out the money for another one unless I know it'll fix the issue (only one way to find out). I went rockford on this setup for the amps because I know they manufacture a good quality amplifier and made a powerful RMS one that allowed me for future expansion.

What other brands of amps are reputable for SQ and push the juice I need? I'm attempting to keep a 1 OHM load because pushing 1KW into a 4 OHM load (other way to wire the subs) will take a huge, expensive amp. I don't mind spending $300-400