horrible computer noise through speakers

**natedawgg** · 02-18-2009, 01:22 AM

Originally Posted by onepuff

So you still had the noise with the headphones? Did you try it without the iMic just the headphones? Have you tested it out in the house? Have you ever opened up the case? I'm assuming you did if you have the y-cable hooked up for the carnetix. Might try opening it up again and see if something has come loose inside. When i added RAM to mine a screw came loose and was rattling around inside causing it to shut down every so often.

actually no. when i tried with the headphones, there was no noise. when i bring the mini inside there is no noise. so i would imagine that means the mini by itself is not the cause of the noise. what i meant earlier is that i have tried pretty much every component by itself, and when you leave out any one component (leaving the system not fully connected through the audio cables) then you have no noise. of course the problem is that i need all of the components in order to get any actual music in my car. this all very perplexing. earlier this evening i tried re-grounding the psu and the amp but this did not help either. it is possible that i just did not find good grounds. either way i am completely out of ideas.

just as a reference i ran across this article that was pretty interesting for all around good car audio practices to avoid any kind of noise. it looks to be a pretty good read either way.

ok well off to see what other things i may have overlooked.

**natedawgg** · 02-18-2009, 01:29 AM

i just had an idea. let me know if you guys think this might help. what if i were to power the amp off of the psu (sounds like a bad idea at first, maybe it is just to late and i am not thinking clearly). The amp is small. it is designed to be able to run on a motorcycle so it doesn't take a lot of power. I was just thinking, it would eliminate any power fluxes and ground loops that could be introducing the noise. of course if i did that i would have to find another way to power the monitor. it did come with a power adapter for the car. it might be worth the try if it would knock out the noise. what do you guys think. does the p1900 even have enough juice to power something like this?

**onepuff** · 02-18-2009, 02:41 AM

I think it's time to get a real amplifier and run new speaker wire straight to the speakers. You can get a small amp for the door and rear speakers for under $100. Then just run some new wire. That's what i would do.

**onepuff** · 02-18-2009, 02:42 AM

Have you tried another headphone jack to RCA adapter?

**natedawgg** · 02-18-2009, 10:31 AM

I think it's time to get a real amplifier and run new speaker wire straight to the speakers. You can get a small amp for the door and rear speakers for under $100. Then just run some new wire. That's what i would do.

yeah i am afraid you may be right. only this really isn't an option for me in the near future (wife has this project on a budget). so in the mean time i will have to either put up with the noise

or just keep trying different connections and grounds until i come up with something.

Have you tried another headphone jack to RCA adapter?

i have not at this point. i would like to go through and replace all of the speaker wire/cabling that i have with higher quality shielded cables. i don't suspect that it will kill all of the noise but who knows. i may be just one bad connection from getting all of this fixed, then again i may be 1 bad amp, 1 bad psu, 1 bad mac mini, from getting all of this fixed

like i said i am going to keep researching and saving my pennies maybe i will come up with a solution, or save enough to rip the whole system out and put new/better components in. Once again thank you everybody for your ideas and help. if you have anymore please keep them coming!

**skizot** · 02-20-2009, 11:49 PM

I know you don't think it is a ground loop you are hearing, but I highly recommend getting this from Crutchfield. I am fairly certain it will help with your situation.

http://www.crutchfield.com/p_127SNI1...filter&tp=2653'

I had the EXACT same problem as you and this solved my issue, unless I turn the volume up to max, which I never, ever have a need to do.

**natedawgg** · 02-21-2009, 05:30 PM

Awesome! i didn't even know they made such a thing. i will give it a try (can't hurt anything that is for sure). thanks for the tip!

**natedawgg** · 03-23-2009, 04:40 PM

Originally Posted by skizot

I know you don't think it is a ground loop you are hearing, but I highly recommend getting this from Crutchfield. I am fairly certain it will help with your situation.

http://www.crutchfield.com/p_127SNI1...filter&tp=2653'

I had the EXACT same problem as you and this solved my issue, unless I turn the volume up to max, which I never, ever have a need to do.

so i ordered one of these over the weekend. i will post back when i actually get it, and let you all know how it goes.

**Crinos** · 03-23-2009, 05:07 PM

I think the noise you are hearing is distortion...

If I read your wiering diagram correctly, you amp the signal two times.. and that will most cases cause a distortion noice. (Much like a distorion pedal for an el-guitar)...

A grounding noice would ingrease with RPM. (Ground noice is produced by the alternator).

**natedawgg** · 03-24-2009, 11:05 AM

Originally Posted by Crinos

I think the noise you are hearing is distortion...

If I read your wiering diagram correctly, you amp the signal two times.. and that will most cases cause a distortion noice. (Much like a distorion pedal for an el-guitar)...

A grounding noice would ingrease with RPM. (Ground noice is produced by the alternator).

you may be right. i always knew that the route i was taking was going to be somewhat hacky. my only alternative is to rip out the factory system and install all new components ( something that my wife or checkbook are not going to let me do).

the only thing that baffles me is if it is just a double amping situation, then why is it when i plug my iphone into the system, replacing the mini as a sound source, then everything is crystal clear?