high whistle from ???

[Kaoseighty9]

my 98 kick is making a high whistle but only some times and only when my radio is on and i did install a new amp and speakers but any one have any idea what it can be so i can start looking?

[longjos]

What is your amp/speaker setup?
It sounds like alternator whine in the signal. (Does it change pitch when the RPMS go up).
It could be as simple as a bad ground wire in your signal path from the head unit to the amp.
The amp could be starving for power.

[Kaoseighty9]

yea it was my alternater it didnt have enough juice it past away few hours ago -.-
but im going to get it suped up so it'll be bigger and stronger btu for what i c i think
the noise now that i think about it was from speakers being to shitty and getting to much power from amp still havn't figgured that out but yes it did get louder when the rpm's went up but the thing is it didnt always do it only random times taht i started it up thats why i got confused.

[jtgh]

all vehicles have alternator whine. ( it generates pulsating DC , it is not a generator)
the key is filtering it out.
a cheap low pass filter does that perfect.
and yes,
bad grounds, bad coax shields , same. (use double shield coax lines)

key to discovery is finding the path. ( path radiated noise)
is it propagating via the primary path (power and ground)
or the Air and then being picked up by signal leads. ( which can be poor)

this is all Ham radio stuff. a million words written it. QST archives....
we had Ham radios in cars before reg. ppl had radios.

I bet you get the noise if you kill the auto source (radio,CD,MP3,sat,..) and
just listen to the amp output. whine........
it will be 200 hertz on up. as you lay gas on the throttle.

there can be hash noise too.

there are tests that can tell you which path is causing the problem.
pulling coax lines. listen.
putting amp onto a seperate 12v battery (not cars) temporarily for test.
may ways to find out.

ways to find out , is it the amp picking it up or is it the audio source whatever causing it.

cheers.

[longjos]

Check the power supply voltage to the amp.
If your alternator was weak and the battery was starting to sag the power supply in the amp wouldn't have enough head room to work with.
If your amp power input is at 10V your going to have some terrible sounds.
That could be intermitant as well. Battery has a good charge, amp has power to work with. Sit idleing for a while, battery starts to sag, amp starts to choke.

[Kaoseighty9]

yea i figured that my 4 130watt lights are taking a bit of power when there off so im makeing a switch from them now thats why my battery is being slowly drained thanks guys

[jtgh]

those lights are High voltage lamps or just incandescent (like simple filaments or ?)
HV discharge type.

if the Lamps on on a relay, then the relay is stuck on , or bad.
id never run anything car (heavy load) with out a relay. never. do that.

the stock switches are expensive and weak.
us the relay it acts as a current buffer.
or use a power transitor. ( common to find today) no moving parts.
IGFETS there called.

[jtgh]

btw , some better gear has better line power filters.
if you need one holler, they are off shelf commercially and you dont have to pay 3 middlemen for "audio pro hype rating"

[Kaoseighty9]

it has a in-line fuse going form battery to a switch which i put in my self then to
a 30 amp relay with out the switch it is drawing a little and since there 130watt
each they draw out alot for just being off so thats why i put in a switch and they
are High voltage lamps.

[jtgh]

just keep in mind ,even a relay coil will drain a battery.

the coil must be to a switch or to the origional factory light switch.
then when that switch is off , no current will flow.

those are real fancy lamps you got.. nice...