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Common problems

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  • Common problems

    I'd like to know what major problems people have ran into while putting together their MP3Cars, and whether anyone out there has used the IRMan in the car.
    HomePage and Mp3Car Setup

  • #2
    The main issue people run into seems to be the interference/alternator whine issue in terms of undesired noise to the speaker system. Correct grounding of the computer power supply, computer case, and the inverter source of power along with use of the Radio Shack 'ground loop isolator' appears to clear up the problem in 99% of cases.


    • #3
      Another problem I've seen people run into is how to get the audio through to the speakers.

      It's fairly easy to do if your car has an aftermarked headunit + amplifier, but if you have a car with a stock stereo system, you may have to resort to using an RF modulator (see another thread on this site for a discussion about these) or a cassette-tape adaptor if your head unit doesn't have a jack on the face or RCA leads in the rear for an AUX input.

      Also, some people have problems running the wires and cables necessary to do a good install of their system. In order to do a clean installation, you'll probably find yourself taking interior panels out and searching under the carpet and seats for places to run power, control and audio cables.

      This is very similar to fitting a stock vehicle with an amplifier and additional/new speakers. Anyone who has done this type of work should be able to do a decent install of a car MP3 player.

      Jason Johnson
      Yorba Linda, California

      MPC Phase IV - *** PENDING ***


      • #4
        Here are some things I did to help eliminate my noise. The first step was making sure the computer's case is grounded (and all the components inside). That eliminates 50% of the noise encountered. The second really good idea is to ground all your audio equipment to the same point in the car. Mine are grounded to where the seatbelt bolts down under my seat. Since I still had some noise I worked on everything again and it ended up that I move the ground for the head unit from the common ground to the computer's case (don't ask me why this worked, but it got rid of the rest of my noise). I still hear a bit of alternator noise, but it is so faint it is almost inaudible. Note, I did not use any Radio Shack noise filters, but I am thinking of running a power noise filter before my inverter to take some more engine whine out, but I am not saying this is a definite fix.


        • #5
          Well as far as alternator whine goes heres what fixed my amp/sunwoofers...i didnt use a common ground because that didnt fix the noise satisfactoraly...what i used was a 'Choke' from Radio sahck. now this is not the same as a ground loop isolator. this device runs inline with the +12v power to the amp (Im assuming the same could be done with the +12v to an invertor or DC-DC convertor) This solved everything...


          • #6
            I have a ground loop inductor from radio shack and that clears the whine and buzz, but I still get a headache listening to music on my mp3 player (or a CD player powered from the cigarette lighter). It sounds fine to my ears, but they start hurting pretty soon so there must be some frequency I can't hear that's giving me a headache/earache.

            Could this be a grounding issue? How could I ground my PS and Inverter, neither has a ground wire attached. Can I just tape a wire to the outside case? What is a choke, what exactly does it do and how much does it cost? Also, can I plug it straight in the lighter or do I have to do some soldering?



            • #7
              Oh, and to answer your other question..

              I have an IRMan mounted in my car. Works great


              • #8
                About your headaches, it's a well known fact that certian frequenceys can cause various things to happen to you. for example between 4-6hz will put you to sleep. Some higher ones 8-15 or so can cause physical pain. The military actualy has sound weapons that will cause enemy soldiers to fall on the ground and soil their pants. The problem is producing these frequencys. No speaker system can produce a frequency that low. A way to emulate these frequencys is to play to separate tones with a DIFFERENCE of 4-6 hz. after a while your brain will interpret the difference of the 2 sounds as it's own sound. this works best in a stero arangment with the 2 tones in different ears. Another example, I recently added another Fan and another harddrive to my home computer. The added hardware caused me to get terrible headaches when my computer was one. I concluded that the Fans were hitting a harmonic with a difference of about 13 HZ. I tightened all the screws on the inside and put some tape around one fan to keep it from vibrating and the problem was solved. I hope this info helped out some.