Initial Problem:
So I drive a 2015 S550 mustang ecoboost manual with the base sound system (4 shit door woofers, 2 tweeters, no sub, no factory amp). I completely redid the sound system I replaced the 4 stock speakers with some nice midrange ones and added a sub. I did this on my own and this was my first aftermarket car audio install. I was on a budget so I cheaped out of on the LOC. Replacing the stereo with an aftermarket one was out of the question because for my car they are expensive and basically fords design is bullshit it makes it way to hard to replace like part of the darsh is would have to be replaced and they don't make a lot of these. So I got this $30 LOC that looked like a childrens toy off of amazon. After getting it hooked up I noticed engine noises in the audio system. Not alternator whine but like deep bassy engine noises. I found an extra wire on the LOC the was labbled audio ground that I didn't connect and I grounded it where I grounded everything else. Problem gone. Let me get this out of the way my grounding was perfectly fine and it wasn't a ground loop issue. Fast forward a couple of month after I replaced the LOC recently with a nice LC7i (The best decission I made) My sound system was 10x better. The bass sounded nice and was punchy and just in general the sound quality was cleaner. But the engine noises were back. I tried noise filters and look at many solutions online to no avail. My car is a manual and without the noise filters I was hearing it at basically any rpm. With the noise filters I only heard it around 2,500 rmp. To add to the confusion if I held my rmp at 2,500 rpm and opened the door the sounds would go away and when I'd close the door it would come back.
Solution and what I learned:
So I learned that newer cars have active noise cancelation (ANC) to eliminate things like road noise. They make headphones for planes that use ANC to eliminate the sound on the plane but not the sounds in the environment around you and it works by using microphones to record the noise of the plane and then it shifts the audio signal 180 degrees out of phase which leads to the sounds canceling eachother out. It works the same way in cars. I looked up ANC on my car and found the spot that the microphone is located and how to unplug it which for me required no tools and took literally and I'm not joking less than one minute. Immediatly the problem is gone I no longer here this annoying sound. Not only were people with aftermarket sound systems doing this but also people who had aftermarket exhausts had the problem too.
How this sound can cause more issues than just being annoying:
This sound was so bad that I actually blew my sub. I was tuning my sub and speakers to be right under clipping at about 70% on my stereo. This way if a song was quiter than others (which some are) I could have it go louder without actually clipping my sub. So I set my stereo to 70% played a test tone and started turning up my sub via the LOC. I slowly turned the knob and all the sudden with out any clipping or suspicious sounds it just goes crazy and blows in less than a second. I turned the knob down to zero very fast but it wasn't fast enough I had to kill the car to get the sub to stop trying to play sounds. So what happened?... (At least this is my best theory looking back) The ANC started to hear my sub as I slowly made it louder and it can't tell the difference between the sub and road noise so it started to cancel it out. But why did that cause the sub to blow? Because the volume on the stereo has no affect on ANC and it will basically send a signal at full volume even if my stereo is completely off and because I was tuning it to be all the way up at 70% volume it getting hit with that heavy base that the ANC tried to reproduce and eliminate at 100% just killed it instantly.
Conclusion:
Now somethings start to make sense. The sound would go away when I opened the door bc ANC turns off when you open the door. I have no clue why that audio ground wire on the cheap LOC initially solved my problem (PLZ if you have any idea I'm very curious). Thank you for reading I hope this helps.
Link to my other post:
www.caraudio.com
So I drive a 2015 S550 mustang ecoboost manual with the base sound system (4 shit door woofers, 2 tweeters, no sub, no factory amp). I completely redid the sound system I replaced the 4 stock speakers with some nice midrange ones and added a sub. I did this on my own and this was my first aftermarket car audio install. I was on a budget so I cheaped out of on the LOC. Replacing the stereo with an aftermarket one was out of the question because for my car they are expensive and basically fords design is bullshit it makes it way to hard to replace like part of the darsh is would have to be replaced and they don't make a lot of these. So I got this $30 LOC that looked like a childrens toy off of amazon. After getting it hooked up I noticed engine noises in the audio system. Not alternator whine but like deep bassy engine noises. I found an extra wire on the LOC the was labbled audio ground that I didn't connect and I grounded it where I grounded everything else. Problem gone. Let me get this out of the way my grounding was perfectly fine and it wasn't a ground loop issue. Fast forward a couple of month after I replaced the LOC recently with a nice LC7i (The best decission I made) My sound system was 10x better. The bass sounded nice and was punchy and just in general the sound quality was cleaner. But the engine noises were back. I tried noise filters and look at many solutions online to no avail. My car is a manual and without the noise filters I was hearing it at basically any rpm. With the noise filters I only heard it around 2,500 rmp. To add to the confusion if I held my rmp at 2,500 rpm and opened the door the sounds would go away and when I'd close the door it would come back.
Solution and what I learned:
So I learned that newer cars have active noise cancelation (ANC) to eliminate things like road noise. They make headphones for planes that use ANC to eliminate the sound on the plane but not the sounds in the environment around you and it works by using microphones to record the noise of the plane and then it shifts the audio signal 180 degrees out of phase which leads to the sounds canceling eachother out. It works the same way in cars. I looked up ANC on my car and found the spot that the microphone is located and how to unplug it which for me required no tools and took literally and I'm not joking less than one minute. Immediatly the problem is gone I no longer here this annoying sound. Not only were people with aftermarket sound systems doing this but also people who had aftermarket exhausts had the problem too.
How this sound can cause more issues than just being annoying:
This sound was so bad that I actually blew my sub. I was tuning my sub and speakers to be right under clipping at about 70% on my stereo. This way if a song was quiter than others (which some are) I could have it go louder without actually clipping my sub. So I set my stereo to 70% played a test tone and started turning up my sub via the LOC. I slowly turned the knob and all the sudden with out any clipping or suspicious sounds it just goes crazy and blows in less than a second. I turned the knob down to zero very fast but it wasn't fast enough I had to kill the car to get the sub to stop trying to play sounds. So what happened?... (At least this is my best theory looking back) The ANC started to hear my sub as I slowly made it louder and it can't tell the difference between the sub and road noise so it started to cancel it out. But why did that cause the sub to blow? Because the volume on the stereo has no affect on ANC and it will basically send a signal at full volume even if my stereo is completely off and because I was tuning it to be all the way up at 70% volume it getting hit with that heavy base that the ANC tried to reproduce and eliminate at 100% just killed it instantly.
Conclusion:
Now somethings start to make sense. The sound would go away when I opened the door bc ANC turns off when you open the door. I have no clue why that audio ground wire on the cheap LOC initially solved my problem (PLZ if you have any idea I'm very curious). Thank you for reading I hope this helps.
Link to my other post:
Add an extra sub or get a new LOC?
Ok so I drive a 2015 Mustang with the bass audio. Which if you're not familiar is 4 factory 6.5" door speakers and 2 tweeters. No factory amp at all no sub. I replaced the stock speakers with some ok speakers that are definetly better than the ones I had but don't play a lot of bass. (this was...
www.caraudio.com
