Greetings car audio enthusiasts! As many of you have noticed, I've been around the car audio and security world for many years, starting my love back in the late 70's before I was even 18. Now at 55 years old I'm still going strong, with no hopes of ever getting sick of quality music from my concert hall on wheels.
Having installed more head units, speakers and amps than I could ever begin to count, I've seen pretty much everything. Heard just about everything. Until now!
I recently purchased a Boston GT-40 4-channel amp. As if I'm still stuck in the 70's, I mounted it under my passenger seat! (9 out of 10 of my amps have been mounted in the trunk.) I do handyman and home maintenance work, so I carry a trunk full of tools. No room for any amps (but MIGHT move this one to the rear seat-back.
My most recent purchase/install was a pair of Audiobahn AMS690H 6x9 speakers. I wasn't happy with the little 6.5" Kenwood 3-ways in the back, so I looked for a nice pair of 6x9's with nice frequency response. These were brand new, never out of the box, and got a killer deal on ebay.
So, the minute I turned on my stereo to hear my new speakers, I noticed one of the 6x9's sounded really muffled. I turned the fader to the rear and noticed the left side was barely playing! I cranked up the volume louder and louder until it finally "popped" into action, and got sound from it. Not sure what the heck that was all about, but it scared me! I thought I bought a pair of refurbished crap speakers that were advertised as new!
Well, my troubles weren't over! Even though I properly adjusted my front and rear gains, and set my front 6.5's and tweeters to run in high-pass, everything from the amp was set properly. And yes, I ran my power wires to the amp on the opposite side of the car as the RCA and speaker cables as I always do.
Last night, I was cranking it up a little during an awesome chill song and the rear speakers started sounding muffled again, this time both of them! I was NOT happy! But then all of a sudden, I heard an ear-piercing high-pitch squeal coming from the speakers! (Sorry, took me a minute to get to the point of this post! LOL!). The squeal was enough to make my ears bleed (thank god it didn't). I've never heard this from any deck, amp or speakers EVER. I wasn't sure if it was caused by the amp or the speakers, but assumed the rear speakers were to blame! I tried lowering the volume all the way down to 0 but the squeal was still there! OMG! So then I turned the fader from front to rear and it was still there until I cranked it way up, then it went away. When it came back, I turned the fader to the front only and heard no squeal. As I turned the fader back toward the center, the squeal was back. But was was strange is it didn't only come from the rear speakers. I could hear it from all my speakers, but only when the fader allowed a signal to the rears.
Yes, the squeal eventually went away. But now I need to diagnose what that was all about.
Anyone have any ideas what it might have been caused by? Was it most likely the rear speakers? Maybe something in the amp? All I know is it sounded like some kind of feedback like you get when you get two microphones too close to each other or a mic next to a speaker. That ear-piercing high-pitch squeal. Yep, that one!
Now I'm afraid to even listen to my stereo for fear something is going to go wrong. But like I said, the deck is installed properly (had it in since last year), the amp is wired and grounded properly, and the problem only happened after the 6x9's were installed.
Any advice or opinion would sure be appreciated. In the mean time, I'm going to start looking for another pair of 6x9's! These Audiobahns are NOT as killer as I thought they were going to be! Only thing they kill are my ears!
Thanks for reading this novel. :)