I have upgraded my head unit, speakers and added a Q-Logic sub box as well as an amp. Everything is great except when I turn the volume up a little it starts to crackle, and then cuts out and sounds muffled. It's almost like it's an electrical short but I checked all my connections and they are good. Does anyone have any ideas? How important is the ground for the Amp? I have it attached to one of the seat bolts, could that cause this or is there something else causing power loss?

I have 4 gauge amp kit so there should be no power loss from the battery, I'm just stumped and I hope it's an easy quick fix that one of you pro's can help me with.

thanks in advance.

 

Little more info- are the main speakers amped? Running off HU? Sounds like the amp is going into protect for som reason..

Jon

 

Its only one of THE most important parts of an install. I would imagine that is one of your problems. Like has been said above, we need a little more detail about whats happening.

Read this thread.
https://www.f150online.com/forums/sh...d.php?t=318034
It will explain some stuff about grounding and why its so important.

 

all the speakers are coming off the amp.............

I think there may be another issue see if you think this could be the problem, I ran all new speaker wires from the amp, heavy gauge. I capped off the old lines just in case I ever put back the stock speakers. Do you think I should unplug the harness since it is basically not running to anything except dimmer and minor stuff?

 

I'm just wondering if the harness is holding it back?

 

This information opens up a whole new can of worms.

1) How, exactly, are the amp, speakers, and subs wired? This is CRUCIAL. If wired improperly, the amp will see a lower impedence than it can handle. This is not good.

2) What amp, what speakers, and most importantly, what subs are you running?

3) Regardless of anything else, you need to fix that ground. I believe it was explained how to in the aforementioned thread.


No, the original harness makes no difference if it is capped off. It will be fine.

I still need more details.

 

The amp is wired with a 4g power line, with fuse in it. 5 channel amp, two back speakers, two front speakers, and sub all running on RCA's from HU to amp, then 10-12g to speakers from amp to speakers and sub. I am splitting the rear RCA's at the amp to go to the sub. I suppose this could be the problem becuase I am not using the sub output from the HU because I have a 4 channel RCA cable. I could run another RCA from sub output to amp input, that is my next move if I can't get this figured out.

Front speakers are component Infinity, rear speakers are 2way Infinity, Sub is10" Infinity. They were in my budget and I'm not going to change them unless they blow out. Amp is phoenix gold 5 channel, HU is JVC.

Anyone have good pix of ground spot, I really don't want to drill unless I have to?

Should I just unplug the harness then or leave it plugged in?

 

The only problem I can see at this point is the ground. If you REALLY dont wanna drill a new hole, you can scrape the paint off underneath the bolt you have it on, and reground it there. That might work...dont know. I usually dont recommend seat bolts, jack bolts, or any other factory bolt for a ground.

What ohm load is the sub you're using? What is the model number on the amp? How exactly do you have the sub wired?

If you unplug the harness from the radio, you will lose power and everything. If the speaker leads are capped off at the speakers, it doesnt matter.

 

It sounds like I will just drill a hole then and get a good ground. Does anyone have good pix or an exact spot to drill? I don't want to drill into some lines ora spot that may cause issues. Also, am I using nuts bolts and washers? Would you suggest any type of weather proofing or rust proofing on the underside?

As far as Ohm load, I have been tinkering with it and it doesn't seem to make a difference right now with the cutting out at high volume, what Ohm level is suggested? The sub just has 10g speaker wire from the amp into the Q-logic box. Not sure exactly which model the amp is but I can find out tomorrow if it is important, it's a Phoenix gold 5 channel.

 

Just get a couple star washers and run a screw through them for ground...

Oh and clean off the paint until you can see the metal!!

 

How exactly do you "tinker" with the ohm load?

The ohm load suggested is determined by the amplifier...which means the model number is important.

 

There is an Ohm dial on the amp, I thought that's what you meant. I'll check it out and get back in a few..........

 

So, the star washer sould go under the bolt but on top of the chassis, then a nut underneath?

 

I think you mean "gain" dial on the amp.

Quick little lesson in electronics and speaker theory.
Each speaker has a predetermined electrical resistance measured in Ohms. Typical car audio speakers are 4 ohms and home audio generally 8 ohms. Just about every manufacturer of subwoofer makes a variety of configurations in there subs such as a dual voice-coil 4ohm sub or a dual 2 ohm sub. You can wire these in numerous ways to reach optimum impedence (another term for ohms) for your amplifier.

Amplifiers are also rated in ohms, but in a different way. They are rated as to what ohm load they are stable at. All amps are stable at 4 ohms per channel, some are stable down to 2 ohms per channel. Some even go as low as 1 ohm (and .5ohm for some old school "cheater" amps) per channel. If you try to go lower than the amp is rated for, it will cause a myriad of problems for the amp. Overheating, going into protect and blowing transistors are all symptoms of an ohm load that is too low.

To acheive the proper ohm load for a given sub, you can go about it a couple different ways.
http://www.the12volt.com/caraudio/wo...s.asp~Q~1~I~42

This link has a wiring diagram for a single 4 ohm DVC (dual voice coil) sub. It also has a link to try out a variety of sub wiring options.

I recommend familiarizing yourself with these diagrams and your amps ratings. Then you can make sure you have everything wired correctly.

 

great info thanks.........