Rvd3b0y Posted June 12, 2006 Share Posted June 12, 2006 New to the forums and have a question: I have an 01 LGT that has the premium soundsystem (4 speakers / tweets), and I just had the head unit replaced with a very nice MP3 deck with aux in, sd card, and USB. Problem is, now my stereo sounds terrible. Previously, I had very good bass response, and decent high and mid range. Now, unfortunately I have VERY clear high end, but no low to speak of. This was professionally installed, and I am wondering if they may have used the wrong wiring harness as I have read that there is a special "amplifier trigger" wire that is often not connected. I would appreciate any help or suggestions. Link to comment Share on other sites More sharing options...
Steiner Posted June 12, 2006 Share Posted June 12, 2006 First thing I'd check is polarity. You don't notice if it's swapped on highs as much as you do on lows. Since the signal is AC, the highs still "vibrate" appropriately but with a wrapped coil speaker (mids, subs) the movement of the speaker will be reversed (pulling in instead of pushing out). Not saying this is the problem but it's an easy thing to check. The kit harness still has to be wired to the aftermarket unit so it's possible a mistake was made. Easiest way is to check without taking anything apart is with a straightened paperclip or other small diameter rigid object. Put it through the grill of the speaker and lightly hold it against the cone with your finger. When the low note hits, you should notice the speaker pushing the paperclip/wire against your finger. If polarity were reversed, you'd fill the speaker "give" when the low note hits. Use a CD with some longer bass notes since with punchy notes are sometimes hard to tell what you're feeling. Don't know specifics about the '01 LGT sound system, but if it uses an external amplifier then that may be an issue as well. Experience is something you don't get until right after you needed it. Link to comment Share on other sites More sharing options...
wcbjr Posted June 12, 2006 Share Posted June 12, 2006 Did you just tell him to poke a hole through his speaker? Because that is what is going to happen if you put a pin up against it. You will most likely have to remove the deck and reverse the polarity of either the drivers or passengers side mid. There are quite a few threads on the lack of bass response. I forgot what I was supposed to remember. Link to comment Share on other sites More sharing options...
Steiner Posted June 12, 2006 Share Posted June 12, 2006 Did you just tell him to poke a hole through his speaker? Because that is what is going to happen if you put a pin up against it. You will most likely have to remove the deck and reverse the polarity of either the drivers or passengers side mid. There are quite a few threads on the lack of bass response. Yes. I told him to physically take a "pin", force it into a speaker, and poke a hole in it. Thank you for clearing that up. Experience is something you don't get until right after you needed it. Link to comment Share on other sites More sharing options...
mbanks21 Posted June 12, 2006 Share Posted June 12, 2006 Or take it to a shop that knows what theyre doing and have them fix it. If they didnt rewire the factory amp/crossovers than itll sound like crap. Link to comment Share on other sites More sharing options...
072 Posted June 14, 2006 Share Posted June 14, 2006 here's an easy way to check speaker polarity- -find a track with good bass response that you know well -while playing the track fade the stereo all the way to the front -now balance it from left to right what you should hear is the bass increase as you balance it back to center. if it stays the same or decreases the speakers are out of phase. you can do this with the rears too. depending on what deck you put in, there might be selectable highpass filters built in. mess around with those. if that fuction is on the radio will not allow the lower freq. to make to the sub. hope this helps. Link to comment Share on other sites More sharing options...
msmith Posted June 14, 2006 Share Posted June 14, 2006 Steiner... the speaker will move both forwards and backwards with music. You can't check system polarity via speaker motion unless you use very specific polarity pulse signal. Link to comment Share on other sites More sharing options...
PGT Posted June 14, 2006 Share Posted June 14, 2006 or a 9V battery hooked in phase to the wiring (provided you know how it was hooked up to the speaker that is) The positive lead hooked to the + terminal on the battery will cause the cone to move forward, while the reverse will cause it to move backwards. * REMEMBER! no warranty on speaker damage with this advice - use at your own risk * Link to comment Share on other sites More sharing options...
wcbjr Posted June 14, 2006 Share Posted June 14, 2006 I've used a AA battery before, but never a 9V. I forgot what I was supposed to remember. Link to comment Share on other sites More sharing options...
PGT Posted June 14, 2006 Share Posted June 14, 2006 yeah....9V might be a bit overkill. AA is better, but a bit hard to see movement on the cone. I used to have a pair of photo batteries taped together and wired up in my toolbox for this quick test......3V I think. Link to comment Share on other sites More sharing options...
msmith Posted June 14, 2006 Share Posted June 14, 2006 9V cell is fine on a component woofer and a crossed over tweeter (don't hold it, just touch it). DO NOT USE A 9 VOLT DRILL BATTERY (a lot more current) Use a 1.5V on an unprotected tweeter Link to comment Share on other sites More sharing options...
Steiner Posted June 15, 2006 Share Posted June 15, 2006 9V cell is fine on a component woofer and a crossed over tweeter (don't hold it, just touch it). DO NOT USE A 9 VOLT DRILL BATTERY (a lot more current) Use a 1.5V on an unprotected tweeter Main thing is to just tap it with the battery. The DC is what kills the coil if held on the contacts. smokey smokey And for all the nitpicking, notice that I said "the easiest way to check" which to me means not having to take anything apart. Sometimes I guess I give people simple instructions and credit for common sense and let them do what they want. If the guy were comfortable with doing a real test, he probably wouldn't have taken his car to a install shop to get the radio installed. I'm full aware of how a speaker moves. However, with a low or mid bass note like a drum kick (not prolonged), it is very easy to tell that the cone does move outward if polarity is correct. Let's turn the "I know more than you" police loose. I'm done with this thread. Dude, just take your car back to the install place and tell them you're not happy. Experience is something you don't get until right after you needed it. Link to comment Share on other sites More sharing options...
PGT Posted June 15, 2006 Share Posted June 15, 2006 dude. chill out. Link to comment Share on other sites More sharing options...
Waxiboy Posted June 15, 2006 Share Posted June 15, 2006 I have always used AA. But when I was hooking up my HT I couldn't make my Polk surrounds budge. Link to comment Share on other sites More sharing options...
Rvd3b0y Posted June 15, 2006 Author Share Posted June 15, 2006 Hey guys, thanks for all of your suggestions. I tested the speakers as suggested, and you were correct. When the HU was installed, the polarity was indeed reversed. I took it back to the installer and after a litte berating they rewired the whole thing and all is good! Thanks again for the help. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.