locating rattles? + fitting a second battery?

[bullyd]

hi all, i finished fitting my stereo equipment today :D and from inside the car shes defening :p but from outside her shes really rattling, sounded like the bumper was loose but ive held various points of it and the rattle is still there! any ideas where it could be coming from?
2nd question does anyone have step-by-step instructions of how to fit a second battery as i was playing with the settings and then couldnt start the car :p so i guess id better think about upping the power coming in :)
a list of what ive fitted :-
2 x jbl 12" subs
1 x earthquake sub
1 x splx sub
4 x 4way 6x9s
2 x tweeters
2 x 2way 8" door speakers in rear doors (not fitted yet so i aint finished lol)
upgraded footwell+rearshelf speakers (still pioneer)
1 x kenwood 1500 watt amp (jbl's)
2 x kenwood 200 watt amps (footwells)
1 x kenwood 100 watt amp (tweeters)
1 x splx 800 watt amp (running 6x9's)
1 x splx 700 watt amp (running 'quake and splx subs)
alpine cd head unit

altogether im running 3900 watts and she is seriously loud without distortion its gotta be heard to be believed!
i will post pics when i can (it was too dark to take them tonight)
thanks in advance for your comment/help with the battery issue!

[Rigmaster]

Hmmm, you put ****-rattling stereo equipment in there and now you want to get rid of the rattles????

Maybe buy a big box of earplugs to hand out to other drivers in your town?


Bret.

[stx133]

there are units available that monitor the current drain from the battery and when the battery gets low opens a contace, this can be used to set a signal to the opperator or to cut power on a relay to accessories. Fitting a seccond battery is ok if you must but always going to be a bit untidy, make sure you get a neat box to mount it in if it is going in the boot. use good heavy cables to connect.
The alternative is to look for a replacement battery, oddesy do good deep cycle batteries that last longer and have more grunt to start motors with after being pillaged by stereo units etc...

How did u mount the 6x9s, i am about to do the same in the rear with some Blaupunkt comp series units, seperate wiring for the woofer and tweeter and an independant crossover.....

[pundit]

hi all, i finished fitting my stereo equipment today :D and from inside the car shes defening :p but from outside her shes really rattling, sounded like the bumper was loose but ive held various points of it and the rattle is still there! any ideas where it could be coming from?
2nd question does anyone have step-by-step instructions of how to fit a second battery as i was playing with the settings and then couldnt start the car :p so i guess id better think about upping the power coming in :)
a list of what ive fitted :-
2 x jbl 12" subs
1 x earthquake sub
1 x splx sub
4 x 4way 6x9s
2 x tweeters
2 x 2way 8" door speakers in rear doors (not fitted yet so i aint finished lol)
upgraded footwell+rearshelf speakers (still pioneer)
1 x kenwood 1500 watt amp (jbl's)
2 x kenwood 200 watt amps (footwells)
1 x kenwood 100 watt amp (tweeters)
1 x splx 800 watt amp (running 6x9's)
1 x splx 700 watt amp (running 'quake and splx subs)
alpine cd head unit

altogether im running 3900 watts and she is seriously loud without distortion its gotta be heard to be believed!
i will post pics when i can (it was too dark to take them tonight)
thanks in advance for your comment/help with the battery issue!
Your brain will turn to porridge, your E34 will separate along every seam weld and you're worried about rattles?!!.

You should first have the whole system EQ'd. Cars are notoriously difficult acoustic enviroments. Many of your rattles are likely to be caused by large non-linear frequency response irregularities. Sometime these can be as much a 20dB in a car environment. However even a linear system operated at high levels will bring out problems right throughtout the range.

Use a sine wave generator plugged into an auxilary input and slowly manually sweep through the frequency range until you hear a buzz or rattle. Stop at that frequency and hold it steady while you investigating the source of the noise. Pushing, flexing & poking the offending area should soon isolate the cause. Then it's a case of either tightening down or adding some dampening material to cure the problem. Once done, keep sweeping up the frequency range until the next rattle or buzz becomes apparent. However if you intend running this thing as loud as I think you intend doing, there is probably little chance of avoiding some audible resonances.

I'm not sure if all the subs are going to work well together. Have you checked their combined phase response? Actually that goes for the entire system. Throwing in a squillion speakers does not necessarily a quality system make!!

[Paul in NZ]

some e34s do have a second battery mounted in the boot but its only a 25 amp hr,backup i think for cars that had a car phone?The battery was conceald behind a more boxy boot liner

http://www.bimmer.info/bmw/kiwi535/battery2.jpg

[bullyd]

Your brain will turn to porridge, your E34 will separate along every seam weld and you're worried about rattles?!!.

You should first have the whole system EQ'd. Cars are notoriously difficult acoustic enviroments. Many of your rattles are likely to be caused by large non-linear frequency response irregularities. Sometime these can be as much a 20dB in a car environment. However even a linear system operated at high levels will bring out problems right throughtout the range.

Use a sine wave generator plugged into an auxilary input and slowly manually sweep through the frequency range until you hear a buzz or rattle. Stop at that frequency and hold it steady while you investigating the source of the noise. Pushing, flexing & poking the offending area should soon isolate the cause. Then it's a case of either tightening down or adding some dampening material to cure the problem. Once done, keep sweeping up the frequency range until the next rattle or buzz becomes apparent. However if you intend running this thing as loud as I think you intend doing, there is probably little chance of avoiding some audible resonances.

I'm not sure if all the subs are going to work well together. Have you checked their combined phase response? Actually that goes for the entire system. Throwing in a squillion speakers does not necessarily a quality system make!!

first of all thanx for the advice pundit, ill try and get hold of a sine wave generator, as for throwing in a squillion speakers that wasn't quite the audio build philosophy i was working to! the 6x9s give a good all-round sound for the basis of the install, the earthquake sub gives punchy bass whilst the splx's plastic cone gives a more midrange bass sound and the jbl's handle elongated bass lines really well! the footwell speakers,door speakers and tweeters are there to insure the whole thing isnt drowned out by bass alone!
it all goes together really well the sound inside the car is crisp the only problem i have is the rattles after i surpass about 1/3 volume!(only audible from outside)

[bullyd]

How did u mount the 6x9s, i am about to do the same in the rear with some Blaupunkt comp series units, seperate wiring for the woofer and tweeter and an independant crossover.....

ill try post pics later today maybe tomorrow :D