Anyone know anything about car audio?

paddy1234, Jan 14, 9:25pm
I had a friend try and install some new front speakers into my car and it appears he has damaged the head unit. We are now getting no sound at all from the left front speaker - new or old speakers. Tested everything, rear and right front still work fine. Checked wiring etc all fine. Has he killed the left front channel on the headunit. Is there any way to get around this if the channel is dead? Can it be wired differently so the left front can work? Its a JVC bluetooth headunit. Any idea?

kazbanz, Jan 14, 9:32pm
Most odvious question--was the left front speaker ever working?
More likely it wasn't and theres a wiring fault.-easiest fix its to run new wires right up to the head unit.
BUT--first--given you don't have any test equipment I'd suggest fitting the new left speaker into the right front and see if its faulty.-it does happen.

paddy1234, Jan 14, 9:46pm
Yes, replaced left speaker was working fine, just putting in some newer speakers.
New speaker has been tested in rear and working fine.

m16d, Jan 14, 10:04pm
turn the balance knob. ?

pericles1, Jan 14, 10:05pm
Make sure the Balance and Fader are set to put sound out to the front. Failing that you may have to install an amp and run the speakers off that now.

stevo2, Jan 14, 10:58pm
Either the wiring is damaged or disconnected for the L/H front channel or that channel has been fried in the headunit. Try running a direct speaker wire from the headunit to the speaker, if it works the problem is wiring. If it doesnt, the problem is headunit.

mad_signtist, Jan 14, 11:03pm
Yeap and dont let "friend" near it again. Must be a boogy bastard to fry a headunit. So easy to take a fuse out to protect it while wiring up.

mad_signtist, Jan 14, 11:04pm
Also if its buggered. Buy a cheap amp and hook that up. Run them all off a 4 channel amp. Better sound and no need to buy a new headunit

kazbanz, Jan 14, 11:09pm
ok so to clarify-you have a jvc headunit with XXXXoutput per channel?
You have retrofitted new front speakers with YYYYY output AND rears or existing rears?
Im just wondering the headunit has enough grunt for the four speakers.
Does the headunit have front/rear bias as well as left/right?

intrade, Jan 14, 11:21pm
ok here is some facts. on new cars fitting a radio can be a problem when you dont know what wires you use to install power etc.
on some radios they have no protection on the audio channel this means once you short the channel the speaker outlet is fryed , as with newer radios some have protection for this mistakingly shortening a channel.
so if one speaker dont works and the wiring is fine you would want to check if it has fried this channel internally you can use the 2 rear speaker and wire them to both front and rear for a cheap fix if it has fried a channel

you have to make sure not to overload the rear channel with now 2 speakers on one rear channel and dont fry any more channels.
removing power for 30 minutes is what i would do to see if the channel comes back to live or not.

flossy64, Jan 15, 12:30am
If you are sure the speaker is ok and want an easy way to test the wire put a 9v battery on the wire at the headunit end (with the headunit wires unplugged) if the wires to the speaker are ok the speaker will crackle.

paddy1234, Jan 15, 7:16pm
of course we have tried that, was the first thing.

paddy1234, Jan 15, 7:22pm
Headunit is a jvc kd r921bt. Speakers being installed in front are Pioneer TS-G1644R. Speakers just installed into the back doors are JVC CS-FS60 (working perfect).

intrade, Jan 15, 7:44pm
get a oszilloscope on the channel that works then on the one that dont , then you know if you got a dead channel. like i said often stereos have warnings about frying a channel with a short in the distruction manual.

intrade, Jan 15, 7:55pm
do you have this manual and did you read it its not my job and i usually send people away with car stereos to install exactly because of problems after that you have.
http://www.jvc.fr/files/instruction_manual/kdr921bte_get0720-003a_fr.pdf

there is filters in there god knows maybe one front and one rearchannel is conected and same on other side and filter is on so the old speaker might have made it passed the filter and new one now dont. and you still get sound because the front that works is actualy a rear channel Who knows , i did only read tru a few pages read the whole manual and if it has channel short overload protection,
also there was something on google about a flash upgrade , but the flash upgrade i would only do if they mention a fix on channel loss . nut just nilly willy messing with flashing= a bad idea.

intrade, Jan 24, 12:32am
well i dont know might be nothing like i said i dont claim that to be the problem its just something that set off my brains alarm when i did read the first few pages of this manual, there might be more if i was to read it all but i got better things to do then try and solfe somons problems over the net for free.
most inportant advise i can give is turn on your brain. i was told this by a guy when i did my aprentice and it works well. when you turn it on you manage to figure things out might be above your head at the time and you might need to study for ages how things work but when the brain switch is in off position you wont ever get to figure anything out.