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Discussion Starter #1
Hello, I'm having a problem with some high pitched white noise coming from the tweeters which becomes irritating after a while, almost like tinnitus. Turning up the volume will mostly drown out the noise but you can still faintly hear it in the background or quiet sections. There is a very very faint noise also coming from the woofers but it is hard to hear anything.

Brief background:
I have recently added a new under seat sub, amp and new 5.25" component speakers
Sub - Kicker 11HS8
AMP - Kicker Key 180.4 with dsp
Component Speakers - Rockford Fosgate 5.25" T-152-s
It is a Suzuki with the stock head unit, with speaker level outputs only.

I have the amp setup as bi-amp mode with the inputs coming from the stock head unit (front L+R speaker level outputs of HU) and the amp turn on set to DC mode, so it will turn on when it detects an input from the HU. The outputs of the amp are run directly to the speakers (I have not installed the passive crossovers supplied with the speakers as suggested in the amp instructions).

The problem I have is that there is a constant white noise coming from the tweeters that I can hear from about 2 feet away. The noise is there as soon as the amp turns on even with the headunit on mute or with nothing playing. It will be there with the car in ACC, on and running. Revving the engine does not change the noise. Increasing the gain on the amp increases the noise but even with the gain set to the lowest position the noise is still there.

I thought it may have had something to with grounding but I have checked the grounds for the amp and measured 0.1 ohms between ground and battery. The headunit had a resistant of 0.6 ohms between ground and battery so I cut the existing HU ground and ran a new ground wire to the amps grounding point (now having a resistance of 0.1 ohms as well). The noise is still there though..

I wonder if the amp just has a high noise floor? 馃槙

Any help would be appreciated, cheers
 

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How does this sound on it?


;)

Some ipother used or smaller amp may be worth a try?
 

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Discussion Starter #5
That song hides the white noise quite well :ROFLMAO:

Whats ipother? The amp is already quite small only 45W per channel. Maybe a L-pad attenuator on the tweeters would work?
 

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"Ipother" is a an iPad spell check version of "other".

I am glad you took that song in humour that was intended.
That amp looks potentially good for woofers and midrange... but any little amp should be plenty for tweeters.

Where are you at in Aus Bruss ?
 

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Discussion Starter #7
Oh that makes sense now, I even googled ipother and couldn't come up with anything haha. I'm across the ditch in NZ.
Ideally, I wanted to keep the tweeters on the key amp so I could use the auto dsp feature for time alignment and EQ. I messed around with it some more this afternoon and temporarily installed the passive crossover and wired it up to the tweeter. Using the attenuation on the crossover (-2db) did make the white noise/hissing reduced, unfortunately -2db was as low as it could go. I'm thinking an L-pad attenuator with -6db or -9db may be able to help get rid of the noise?
 

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I think that the attenuator would need to be between the amp and speaker...

A second had amp seems like a surer thing?
 

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Is the signal taken directly after the radio or is there a factory amplifier you're taking the signal from? Could be a high noise floor but those are made to be used with factory systems. Is there a selectable gain setting?
 

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I think He said it makes it with the RCAs unplugged...
 

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Discussion Starter #11
The signal is taken directly after the stock radio/head unit, no factory amplifier in the car. The noise is still there with the inputs unplugged though.
There's no selectable gain switch (Hi/Lo), just the usual gain dial. The input sensitivity of the amp mentions 250mV-10V. With the gains in the lowest position the amp output will start to clip with the headunit volume around 75%.

I recently just swapped in another amp (same model) to check if the amp was faulty and still had the noise. So I guess that rules out a faulty amp..

I downloaded a frequency analyser app, not sure how accurate it is though and got the below reading with the phone microphone by the tweeter (yellow) with nothing playing. The peaks at 4.5kHz, 6.9kHz and 12.8kHz seems odd?

278629



With the amp disconnected I noticed another odd reading. This was with the microphone right by the dash instrument cluster. There was also the same 15.6kHz reading down near the kick panel but at a lower dB. The power cable for the amp is run down by the kick panel. Could this high frequency noise somehow be coupling into the amp's power cable and causing the noise issues?
278630
 

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might not help, but unmount the amplifier and move it around. it might be picking up on noise from a CPU or fuel pump?

if you have a DSP, or EQ then knock down the 15khz band. if you have a PEQ you should be able to dial right on it and kill it.
Sorry I reread it. its coming from the amplifiier dirrectly. EQ wont help
 

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I would test it on a bench.

  • It is possible that somehow noise is getting in.
  • And also possible that the amp itself is bad, or that it is switching noise from a class-D circuit.
 

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EDIT: sorry original post deleted out the first part of my reply.......

The outputs of the amp are run directly to the speakers (I have not installed the passive crossovers supplied with the speakers as suggested in the amp instructions).
Probably not...but you aren't running a full range signal to your tweeters....?

Hopefully not...in which case the sound has to be coming from either the amp. the speaker cable, or the tweeter...as minibari suggested; moving the amp could help...also are your tweeter cables running next to any power cables? Pretty unlikely to be the case but that's all I can think of...
Ki ora as well mate (y) I've lived in Australia 30 years but I really think it's about time I moved home to NZ...bloody Covid
 
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