Subwoofers causing door and dash speaker distortion(?)

[StoneBullet]

Ok, so I put off getting my ghost flames painted on my 07 so I could finish my audio system. This is what I ended up with

Alpine CDA105 head unit
Boston S35 3.5" dash speakers
Alpine SPS 6.5" door speakers
Got rid of the rear speakers. They're pointless
2 12" JL W1V2 subs in a ported box
Rockford P200-1 pushing the door and dash speakers
Rockford P500-1 pushing the subs

Ok, so when I kill the subs and turn the volume up, the door and dash speakers sound great. However, when I add the subs at a moderate level, I get distortion from the dash and door speakers. I could take my car to a shop and pay who knows how much to get it fixed, but I thought that I would check on here first to see if anyone knew of a cheap fix to this problem. Thank you for any advice anyone may be able to provide.

[darkpt06]

you could have a possible grounding issue. Or need to purchase some type of cap.

where do you have your amps grounded to??

[bobdole369]

No point in a cap, like pissing in the wind. Ground the system better. period. 4 AWG from a very good (read NEW, as in drill the hole, tap it, put it in yourself) ground point to the negative terminal of the battery. Connect the alternator and engine block to the same point. Run your ground cable for your amplifiers from that same point.

Also you should have at least 4AWG from the positive terminal of your battery, through a big ole fuse (like 50-100A) within a few inches of the battery. Make sure you grommet any hole the 4AWG runs through, esp through the firewall. Use a good quality distro block at the amps, each line should be fused in addition to any fuses the amps/crossover/processor uses.

Quite likely when you turn on the subs you are using a bit more power, and the PT is known for terribly ground loops/lost voltage/drops from any run into the back hatch area. You pull a couple hundred watts and its voltage drop city. It's quite good advice to search "hypergrounding" on this forum.

What are you using for a crossover? Perhaps you are loading the processor/crossover and thats causing a mismatch elsewhere in the system?

[StoneBullet]

I actually have 2 power wires coming off my battery. One is 8awg for my P-200 and I have a 4awg for my P-500. The same goes for the grounds. I have a 40 amp fuse on the 200 and a 100 on the 500. As far as my crossovers, I'm using the ones that are on the amps.

The thing that confusing me is if I have a voltage drop when my subs are getting pushed fairly hard, wouldn't my lights dim? If it were a voltage drop, wouldn't hooking up a 1 farad cap fix that problem?

My initial thoughts is that maybe my speakers aren't sealed very well, causing my speakers to "flutter" whenever the bass notes hit. I'll do whatever is necessary to get rid of this problem, but I'm not about to mess with the "Hypergrounding" thing you just described. I'll pay someone to do that.

Darkpt06--I have them grounded next to the latches that the rear seats hook on to.

Sorry if that didn't make too much sense. My sleep medication is kicking in.

[darkpt06]

Ok well that ground may not be the best ground. thats most likely your issue

i have my sub amp and highs amp grounded to the bolt NEXT to the drop down bolt for your spare tire, and i have no feedback.

the power wire may not be an issue but you maybe limiting your self with power due to the gauge of the wire your using.

for example, i have a One 4gauge power wire running to a Fuse box and from there splits into 2 wires going to my amps.

what you said about the dimming of the lights is a problem that would be fixed by a cap.

If you didnt no or for the people reading this that do not know, caps are used to store extra voltage, that extra voltage is used when you get a spike in power (ie when you subs hit), thus if you do not have a cap, and you getting dimming headlights and gauge lights you would have to purchase one to keep that from happening.

i personally do not have a cap in my car.

[bobdole369]

I actually have 2 power wires coming off my battery. One is 8awg for my P-200 and I have a 4awg for my P-500. The same goes for the grounds. I have a 40 amp fuse on the 200 and a 100 on the 500. As far as my crossovers, I'm using the ones that are on the amps.

Wonderful. So you aren't getting a voltage drop. You can verify with a meter, connected AT the amps, but I think you are OK with that setup.

The thing that confusing me is if I have a voltage drop when my subs are getting pushed fairly hard, wouldn't my lights dim? If it were a voltage drop, wouldn't hooking up a 1 farad cap fix that problem?

Nope. a 1 farad cap actually compounds the problem. You need to recharge the cap, further pulling down the system. To actually fix a voltage drop like that the way is with a filter, with a big ole coil and small cap combo. It requires some engineering, but the best fix is to solve the cause of the voltage drop. i.e. upgrade wiring, increase battery capacity, upgrade alternator, etc. You don't need to do this, its already done.

Quite possible you get a ground loop going when power draw is heavy. Try running a heavy gauge from the head unit to the neg on the battery too. Just a thought there, since your head unit gets ground through the dash, which is generally pretty poor.



You do have the high-pass on the non-subwoofers going right? so you aren't sending bass to your door and dash speakers? Just checking.

[chris15]

As bobdole stated, I'm almost certain the problem lies with your sub amp. If it isn't the sub amp, then it could possibly be crossovers.

You even stated that when the sub is off, the front speakers sound fine, but when the sub is turned on, you end up with distortion. This is most likely caused by a grounding issue or (though this is quite unlikely) your RCA/speaker wires are too near your power cables. I had this same problem in my PT.

To check to make sure that it's just the amp, disconnect the subwoofer from your amp, but leave the amp connected and ensure that it turns on with your deck. This negates the effect of bass on your hearing. If you still have interference when the sub amp comes on, then it's definitely one of the two issues I just mentioned.

I patched the problem temporarily by adding a ground loop isolator ($15 or so at Radioshack) but eventually I looked into the theory of hypergrounding and ran a couple wires from my battery to 3 places: common ground point in the engine compartment, the ECU and the camshaft position sensor. I was skeptical of its effectiveness, but figured I'd test it out. I removed the ground loop isolator and no longer had any interference whatsoever.

Now, my problem is that I'm pushing 1200+watts RMS total and even the hypergrounding deal is keeping my headlights from dimming and I need to install a cap.

[StoneBullet]

Chris15--My sub amp is always on. I kill the bass by using my subwoofer gain on my head unit. I know I have a ground loop because I hear that turbo-sounding whine when I accelerate and have the stereo at a low volume. I remember way back in the day that a local radio shop fixed the ground loop I had in my 72 Dart by running a wire (I have no idea what it was from) into one of my RCA wires. For $15, I think I'll try one of those ground loop isolators. If that doesn't work, I'm too busy with my kids (I'm a single dad) and college to mess with anything more complex, so I'll just take it to the pros and have them figure it out. Then I'll have to put off getting my baby moons

Of course I have the High Pass filter running on the 200! The worst part about all this is if this had happened 10 years ago, I'd have all this fixed with no problem. I figured the 2 years of electronics I took in high school would help me with all this...

Once again, thank you all for your help. I really appreciate it.

[darkpt06]

>.> hmm you do you have ur sub amp bridged??

[bobdole369]

I kill the bass by using my subwoofer gain on my head unit.

Disco.

When you turn it back on (by increasing the gain on your head unit) you are changing the output of all channels. (yes confusing but hear me out) Could be that your overloading the preamp outputs on the head unit when the gains are up. Any way to reduce the output of the head unit (such as limit the volume and compensate by slightly increasing the gain of the amps?)

Recall that each output is likely on a common voltage rail, so that when you crank the sub up, the preamp output on all channels suffers.

I know on my head unit, I have a max volume setting of "30", but everything above 27 gets distorted and clips. When I use the in-built EQ and set anything above "+3", then I must limit the output to under 25 or the same thing happens.

Perhaps set the EQ or any gains to Flat (or 0) and see if it happens there. I'm starting to suspect the head unit is part of the issue here.

thus if you do not have a cap, and you getting dimming headlights and gauge lights you would have to purchase one to keep that from happening.

nah, PT cruisers are noted for poor grounding. I fixed my own headlight dimming with a 4AWG to the chassis from battery neg.

Caps are a bandaid and likely cause further issues.