Car audio help

[maroonandwhite]

Hey guys I have this posted on another website so I'll just copy and paste my post. I'm having a little issue with my new audio setup in my truck and am hoping someone else may be into car audio on here. Thanks

Ok here is my setup:

Factory HU ran to a Audio Control LC2I Line output converter.

LOC to 2 channel amp for doors and a seperate 2 channel bridged to my sub.

Per the instructions that came with the LOC I should set the volume of the HU 3/4 of the way up and slowly turn the gain knobs on the LOC (one for full range and one for bass output) until the maximized light starts blinking. I am assuming this means the signal is clipping. I did that but when I go to set the gains on my amps they basically have to be all the way down in order to not distort the speakers. They sound good now but I can hear a small hiss and I am sure the levels are not set correctly. I know the purpose of the gain knobs is to try to "match" the output of the radio to the amp or something like that but if someone could give me some pointers I would appreciate it.

Also this LOC has the Accubass feature which is supposed to correct the factory bass rolloff of the HU but I didn't really notice any so I left it off.

Thanks

[piercedan]

Output to the amp sounds too high. Also, for the hiss, I would reground everything just to make sure.

[maroonandwhite]

Thanks man. Yeah I will do that but I thinks it's a level issue. I already had everything in my system just changed back to the factory HU so the grounds were good before. Would you think I should just put the levels on the converter about middle ways up? If I set it like I normally do my amps I would take it down about a quarter turn once I see it is distorting or clipping or in this case the llittle maximize light coming on.

[Guest uofmeet]

I would probably bump the volume down on the converter. Basically, you have 2 volume controls and a master volume. Just have to play the match game it sounds like.

I would probably set the gain on the amp to about middle, and adjust converter til I was satisfied.

[maroonandwhite]

Yeah that's what I figured. Do you think it would affect the actual sound of the system if I had the gain on the amp higher than the converter or vice versa?

[peejman]

Most amplifiers produce their maximum output at about 50%. You get clipping and/or distortion beyond that. So, I'd start by turning the volume on the head unit down to below 50% and work from there. And re-check your grounds and wire paths.

[Guest TennTitan]

This is just a suggestion on the hissing noise. Do you have your power cable running along to your amp with the RCA cables together? Sometimes you can get a static/hissing or engine noise if you run them together. Running them where those two are touching or side by side then the power cable transfers engine noise to the RCA cable and you can hear it in your speaker. I usually run the power wire from the battery down one side of the vehicle and the RCA's on the other side. If your RCA cable has a thick jacket on it everything should be good, if not you may be getting an unwanted signal coming off that power wire. other than that uofmeet had a pretty good idea. hope everything gets worked out.

[Murgatroy]

Good advice.

I would turn the LOC down. Half, maybe less. I never liked using an LOC, but if you had to, I never tuned with the HU higher than 50% or the LOC higher than 50%. Like mentioned above, set the gain on the amp at 50% and tune from there. Tune the LOC, not the amps.

Make sure your power cable is separate from any other cables, you don't want your patch cables (in this case the LOC signal wires) or the power cables to the LOC since it sounds like it is a powered source anywhere near your signal cables. This includes your remote turn on for the amps. I tend to run power on the same side of the car as the battery, and the patch cables on the opposite side. You also want the shortest possible ground. I despise anything more than a foot for a ground strap.

[zapfbroad]

You didn't specify what your power loads of your amps to speaker wattage are, if you've got a 4-500w 2 chan amp at 4ohm running to some 50-65w rms 2 way speakers even lo gains May give distortion . If youre running some 8gauge wire u may want to upgrade to 4gauge. Have you done the big three yet? Id start with adding a ground loop isolator if this hissing is coming with the motor on.

sent via EPIC4G SyndicateRomFrozen 1.2

[maroonandwhite]

I put the LOC behind the HU in the dash so I am using those wires for power and ground. I am almost certain the hiss is gain/level related as all the wires are routed like you have recommended. I will try that with the amps half way up. Also at Murgatroy: I never have like LOC's either but I like the factory look and this active LOC seemed to be my best bang for the buck. I am usually pretty good with an aftermarket radio as I only have to set the levels on the amp. I'm all confused since I have one extra now though! Thanks for the advice and keep it coming!

[maroonandwhite]

@ zapfbroad. I am running 75w rms to each door component and 100w rms to my 8" sub. All at 4 ohms and matched with the speakers ratings. 4 Gauge wire from battery to a dist. block and 8 gauge to each amp from there.

[maroonandwhite]

Just to clarify this is not an engine noise hiss that whines when I accelerate or anything. It can be heard when the vehicle is off. I quieted it down by turning my amp gains all the way down and I think changing the level on the LOC is going to correct the problem. I am mainly wondering now the best process to set these gains (Murgatroy pretty much answered it I hope). Thanks!!

[G27]

The noise you hear is due to improper gain-staging - turn the LOC down and run the amp at 75% or so of the gain trims. Them set the LOC so that your volume control on your HU is where you want (say, 3/4 of the way up, set the LOC trim so the level is where you want the 'max' listening level to be.

Forget grounding, if you had grounding issues you'd hear alternator whine following your engine RPMs.

Assuming a clean signal feeding the amp, you have a FAR greater chance of damaging speakers with too little power than 'too much'. Amplifier clipping damages more voice coils than anything.

[M4sherman]

I just take it to jim at collierville car audio . he has done 13 systems for my family and all of them have lasted for 8 years or so and he does not skimp on the work. I will send you his number if you need it

[maroonandwhite]

Thanks man. I'm familiar with him. I think I bought a dash kit or something from him. I usually do my own stuff (we see how that turned out haha) but thanks anyways!