Mazda Rotary Club

General => General Technical => I. C. E. & Electrical => Topic started by: M@r]{ on February 19, 2006, 09:21:13 AM

Title: Just fitted sub - feedback help
Post by: M@r]{ on February 19, 2006, 09:21:13 AM
Guys, ive just fitted the sub, amp and box in the boot of my FD.  Its all working great but I do have one problem.  When eer I turn the head unit on I et a very loud \'bang\' from the sub - as the amp turns on I suspect.  I reckon it may be an earthing issue but where?  At the amp (most likely) or at the stereo?  Ive earth the amp to a bolt that screws into the boot floor.  Im lucky that my battery is in the boot - shall I try earthing it direct to the battery?  Could that cause any problems?  It is a simple install so im a bit lost.

even better, any ICE guru\'s within 50 miles of MK who wouldnt mind an ICE amateur using an excuse to drive somewhere to come and visit to get help?  :)
Title: Just fitted sub - feedback help
Post by: Turbotez on February 19, 2006, 11:49:13 AM
pretty much every install ive done, ive always used a tec screw for the earth an necer had any problems, it does sound like an earth issuse but i wouldnt recomend going to the battery. Have a play with the earth and also generally check the whole wiring of the system. could be a loose wire or somethin. f i was a little closer id come and have a perv at what youve done, but im a bit too far away. Hope this Helps

Turbo
Title: Just fitted sub - feedback help
Post by: RobbieRX-7 on February 19, 2006, 12:13:10 PM
have a mess with the switches on the amp. You have wired the sub in bridged mode haven\'t you? ALso you dont want the gain control up to high. You want it about half way.
Title: Just fitted sub - feedback help
Post by: M@r]{ on February 19, 2006, 01:06:28 PM
Thanks for the info, I\'ll have a play with the earths to see if it makes a difference.

I have got the gain turned right up - but had to to get any real power through it (which in its self is odd as its a decent Kenwood amp, Infinity 12" sub and a decent alpine head unit)
Title: Just fitted sub - feedback help
Post by: dj_dee99 on February 19, 2006, 04:05:29 PM
Might sound stupid, but are your RCAs connected correctly at both the stereo & amp ends? And are the connections between the amp & sub the correct way round?
Title: Just fitted sub - feedback help
Post by: shaunwil on February 19, 2006, 05:59:18 PM
The only other thing is how thick is the negative cable running to the battery. You may be over running the cable with the stereo connected. Have you cleaned off the terminal with emery before fitting the bolt into the body ??

Could be a bad earthing spot in the boot, sometimes if the panel isn\'t welded rigt or is just isclotated you won\'t get a good earth.

Shaun
Title: Just fitted sub - feedback help
Post by: ruffryder on February 19, 2006, 07:22:50 PM
if not your earth i think it could be your remote wire
where is it linked to ?

the only time its happend to me is when the main power to my amps came on with ignition
Title: Just fitted sub - feedback help
Post by: M@r]{ on February 19, 2006, 09:45:11 PM
I have it (temp.) wired to the feed to the electric aerial.  But I dont think thats the problem.  The amp comes on with the igntion where the bang I get is when the head unit powers up.  There is a ground connection on the amp next to the Remote connection - I havent connected it up.  Do you think that could be the problem?  

Quote from: ruffryderif not your earth i think it could be your remote wire
where is it linked to ?

the only time its happend to me is when the main power to my amps came on with ignition
Title: Just fitted sub - feedback help
Post by: RobbieRX-7 on February 19, 2006, 09:49:08 PM
i still reckon it the gain control. Turn all the nobs half way and see if it does it again.
Title: Just fitted sub - feedback help
Post by: ruffryder on February 19, 2006, 09:54:57 PM
ok sorry you saying that thers a ground /earth connection next to the remote one on the amp thats not connected ? is that not your earth ? if that wasnt connceted dont know how it will work , im sure you must mean somthing else ?

ok im sure you should connect the amp remote back to the stereo there should be a wire for it give that a try ,

 and if you have more then one amp make sure all the earths/grounds are to the same place and like some else suggested scrap the paint of so you get a good connection
Title: Just fitted sub - feedback help
Post by: M@r]{ on February 19, 2006, 10:03:55 PM
Yeah, pretty sure it is a ground connection.  The main earth is a large connection next to the Main power feed.  

Maybe that is it, the Amp is powering up before the stereo ie with the ignition, but then the Head Unit switches on and causes the feedback?  Not really an answer to the problem as it shouldnt do that, but possibly a way of stapping it from happening.  The only doubt I have is it used to do this when in was all fitted in My S2000 and if I remember correctly that was connected using the proper remote lead??



Quote from: ruffryderok sorry you saying that thers a ground /earth connection next to the remote one on the amp thats not connected ? is that not your earth ? if that wasnt connceted dont know how it will work , im sure you must mean somthing else ?

ok im sure you should connect the amp remote back to the stereo there should be a wire for it give that a try ,

 and if you have more then one amp make sure all the earths/grounds are to the same place and like some else suggested scrap the paint of so you get a good connection
Title: Just fitted sub - feedback help
Post by: ruffryder on February 19, 2006, 10:12:39 PM
ok well i would suggest after checking the earths you check the RCA\'s then, i do remember having this problem for a while cant rember how i got rid of it thought it was the remote wire ?

which amp do you have ?
Title: Just fitted sub - feedback help
Post by: M@r]{ on February 19, 2006, 10:33:15 PM
not sure on the Amp, its a Kenwood but not sure on the model. I\'ll check tomorrow.  Its one of the ones with the little sliding door and small blue neon power on light.

Quote from: ruffryderok well i would suggest after checking the earths you check the RCA\'s then, i do remember having this problem for a while cant rember how i got rid of it thought it was the remote wire ?

which amp do you have ?