"Microphone Effect" from new Sub
Thread Starter
Teching In
Joined: Nov 2003
Posts: 10
Likes: 0
From: Anchorage, AK
"Microphone Effect" from new Sub So, here's what's been installed by a very reputable company w/ great installers....
Eclipse deck, JL 6.5 VR components in the doors, JL 5.25 VR components in the very back, and a set of JL 6WO's in the sail panels all powered by a JL "e" series 6450 six channel amp rated at 45 watts RMS at 4 ohms
So, here's the problem....
When the system was powered up at the shop with the car off, it ROCKED. It was very loud, very clear, and more bass than I expected out of a 6.5 inch woofer. When the car was turned on and at idle, it was performing just as well. I got in the car and started it to leave the shop, put it in reverse, and the passenger side woofer in the sail pannel started making a wierd hum. The hum went away with the sub pulled out of the sail panel. The "lead" installer said the sub was basiclly acting as a "microphone" because of the exhaust being run on that side of the car. After spending 2 hours on it and even replacing the sub, on a prayer, no avail. With the sub out of the hole, there is a stamped hole in the sheet metal allowing access to the fender well. The installer even used a piece of dynomat to block off the hole, but that didn't do any good either. Now I have a brand new system that is a sub short. I was curious if any of you have experienced this and what you did to fix it. I'm up for any suggestions at all.
BTW...it's a 99 TA w/ t tops completely stock except for audio.
Eclipse deck, JL 6.5 VR components in the doors, JL 5.25 VR components in the very back, and a set of JL 6WO's in the sail panels all powered by a JL "e" series 6450 six channel amp rated at 45 watts RMS at 4 ohms
So, here's the problem....
When the system was powered up at the shop with the car off, it ROCKED. It was very loud, very clear, and more bass than I expected out of a 6.5 inch woofer. When the car was turned on and at idle, it was performing just as well. I got in the car and started it to leave the shop, put it in reverse, and the passenger side woofer in the sail pannel started making a wierd hum. The hum went away with the sub pulled out of the sail panel. The "lead" installer said the sub was basiclly acting as a "microphone" because of the exhaust being run on that side of the car. After spending 2 hours on it and even replacing the sub, on a prayer, no avail. With the sub out of the hole, there is a stamped hole in the sheet metal allowing access to the fender well. The installer even used a piece of dynomat to block off the hole, but that didn't do any good either. Now I have a brand new system that is a sub short. I was curious if any of you have experienced this and what you did to fix it. I'm up for any suggestions at all.
BTW...it's a 99 TA w/ t tops completely stock except for audio.
TECH Senior Member
Joined: Apr 2004
Posts: 6,157
Likes: 1
From: Texas
The mic thing is crap. If this was true it would do it in drive also, as there is no difference (as far as exhaust is concerned) between sitting in drive and sitting in reverse. The only differences are with the tranny.
You say there is a hole in the panel that holds the sub. Its quite possible that the whole has made the structure weak and allowing it to vibrate at certain rpms. Theres no way I would ride around with a speaker missing from that panel. I would take it back and see what they can do, if they cant fix it I would want a refund(partial maybe).
With it installed....and you holding the pannel does it do it? Have you tried this yourself? I bet it the pannel or something close to it is viberating. Go try it out yourself and let us know.
You say there is a hole in the panel that holds the sub. Its quite possible that the whole has made the structure weak and allowing it to vibrate at certain rpms. Theres no way I would ride around with a speaker missing from that panel. I would take it back and see what they can do, if they cant fix it I would want a refund(partial maybe).
With it installed....and you holding the pannel does it do it? Have you tried this yourself? I bet it the pannel or something close to it is viberating. Go try it out yourself and let us know.
Launching!
Joined: Mar 2005
Posts: 257
Likes: 0
From: H-Town
I'm with 2MuchRice, although I did kinda laugh at the installer's 'excuse'... It seems pretty obvous that you've got some sorta resonation from something, even if it is the exhaust. The key would be to do what he said above - locate the vibration. Get someone to sit in the driver's seat with the car running in gear, to the point that the rattle or vibration occurs. Now, sitting in the back seat, push on different areas in an attempt to locate the exact source of the rattle. Again, sorry to laugh, but it's at the installer's complete bullshit excuse (I professionally installed high-end systems myself).
I also agree that I'd demand some sort of satisfaction based on the fact that you paid for and expected a professional installation with no issues, and instead you got excuses (the lamest I've heard, BTW). Again, I really am not insulting you, your decision to go to a certain shop (I bet options are limited where you're at), or anything about your ability - I just can't believe someone who calls themself an installer would come up with such an off-the-wall story for their problem. Let us know what you find - we'll help with whatever we can.
I also agree that I'd demand some sort of satisfaction based on the fact that you paid for and expected a professional installation with no issues, and instead you got excuses (the lamest I've heard, BTW). Again, I really am not insulting you, your decision to go to a certain shop (I bet options are limited where you're at), or anything about your ability - I just can't believe someone who calls themself an installer would come up with such an off-the-wall story for their problem. Let us know what you find - we'll help with whatever we can.
TECH Enthusiast
Joined: Sep 2004
Posts: 598
Likes: 0
From: Midland, TX
The hole in the panel is just to clear the magnet. The hole is in the inner body panel giving access to the outer quarter panel. These holes come factory and should not produce any problems with aftermarket speakers unless you just install a speaker with a magnet so large that it doesn't fit. You may even be experiencing body vibration from being in gear and if the magnet is larger than stock, it may be vibrating between the magnet and the inner panel. If this is the case, just file down the hole to make it larger in diameter. Take some measurements first and see if the magnet is too close to the panel. If this is not the problem, take it to another audio shop and ask them. They shouldn't bullshit you since they didn't install it.
Thread Starter
Teching In
Joined: Nov 2003
Posts: 10
Likes: 0
From: Anchorage, AK
The stereo shop told me Saturday night to bring it back on Monday morning and they will get it fixed. But I am not that patient. I spent time on the phone with my brother 02Denali in Houston. He suggested something sooo simple, I'm shocked it wasn't tried at the shop. I hooked the driver's sub up to the passenger side of the amp, and wouldn't you know it, the driver's side sub was humming!!!! When I hooked the passenger side sub up to the driver's side of the amp, it worked perfectly also. 02Denali and I both think the problem is in the passenger side channel on the amp itself. I'll suggest the stereo shop do the same and see what conclusion they come up with. Hopefully this makes sense to you guys.
