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how to fix subwoofer noise

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wang

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recently I bought a 2nd hand Klipsch sub 10 10" subwoofer. After go home and found that there is strange noise.

I use a 3.5mm-RCA cable to connect mobile phone to the RCA input of sub woofer. Run a few special sub woofer test song from Youtube.

1. Power on connect to mobile phone, turn to the subwoofer volume to half, turn the phone volume to max. all good, no noise
2. Start playing a subwoofer test song, when the song's volume is low, it's all good. When the strong base came, in addition to the strong base, there was some kind of mid-high range noise came out of subwoofer box, it's hard to determine where it's coming from. Some of songs are very obvious for the noise, some of them are less obvious.

3. I suspected something loose in the speaker box. I open the amplifier plate and pull it out to inspect. The fixture of various components are pretty good, nothing loose at all. I use hand/finger to check anything inside speaker box but could not find anything loose.

4. I suspect the woofer drive broken (speaker coil or something else). I plug the power cable and play the song again, the noise gone even I turn the sub woofer volume to 3/4 volume (that's pretty loud). The woofer drive deliver clear and strong base without any noise.

5. But whenever I put the amplifier plate back, the noise came back again. I use my body weight to hold the amplifier plate to stop the vibration of the speaker box and amplifier plate. But it does not help to stop the noise. But even I just open a small gap between amplifier plate and the speaker box, the noise gone again.

I have another 10" subwoofer at home. I tried to test it using the same approach, there is no noise.

The problem is driving me to crazy, any comment and suggestion are appreciated.
 

MaSh

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recently I bought a 2nd hand Klipsch sub 10 10" subwoofer. After go home and found that there is strange noise.

I use a 3.5mm-RCA cable to connect mobile phone to the RCA input of sub woofer. Run a few special sub woofer test song from Youtube.

1. Power on connect to mobile phone, turn to the subwoofer volume to half, turn the phone volume to max. all good, no noise
2. Start playing a subwoofer test song, when the song's volume is low, it's all good. When the strong base came, in addition to the strong base, there was some kind of mid-high range noise came out of subwoofer box, it's hard to determine where it's coming from. Some of songs are very obvious for the noise, some of them are less obvious.

3. I suspected something loose in the speaker box. I open the amplifier plate and pull it out to inspect. The fixture of various components are pretty good, nothing loose at all. I use hand/finger to check anything inside speaker box but could not find anything loose.

4. I suspect the woofer drive broken (speaker coil or something else). I plug the power cable and play the song again, the noise gone even I turn the sub woofer volume to 3/4 volume (that's pretty loud). The woofer drive deliver clear and strong base without any noise.

5. But whenever I put the amplifier plate back, the noise came back again. I use my body weight to hold the amplifier plate to stop the vibration of the speaker box and amplifier plate. But it does not help to stop the noise. But even I just open a small gap between amplifier plate and the speaker box, the noise gone again.

I have another 10" subwoofer at home. I tried to test it using the same approach, there is no noise.

The problem is driving me to crazy, any comment and suggestion are appreciated.

Did you try another source? RCA input on the sub is meant to be connected tp a Sub pre out from a receiver or stereo amp, not a mobile.

MaSh
 

wang

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Did you try another source? RCA input on the sub is meant to be connected tp a Sub pre out from a receiver or stereo amp, not a mobile.

MaSh

I did not. There's no sound from the subwoofer when I play 2-channel music from my receiver, sound comes from 2 front speakers only.

I used the same approach to test another subwoofer. There is no such issues. I believed the subwoofer can take full-frequency signal and filter out mid-to-high frequency.
 

wang

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Did you try another source? RCA input on the sub is meant to be connected tp a Sub pre out from a receiver or stereo amp, not a mobile.

MaSh

I tried different song but did not try the pre-subwoofer out from the receiver. When I played 2-channel songs, sound comes out ONLY from the 2 front speakers, no sound comes out from the subwoofer.

I tried another subwoofer which did not have similar problem.

I guess there is filter inside subwoofer to filter out mid-high frequency. I guess there is only low frequency signal from pre-subwoofer output of receiver.
 

efernand1

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Hi

A proper shielded sub woofer cable should be used!

Also I agree with Mash
 

nindo

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Considering its a powered sub, ideally it should be connected to a pre-out from a receiver/DAC.
I guess even the subwoofer testing sound that you are using from youtube is also supposed to be used in a similar fashion.
The signal from your mobile phone is already amplified to a certain extent considering the fact that you are not using a USB DAC connected to the phone.!
Plus, of course, signal interference to a regular RCA cable instead of a designated sub-woofer cable.
 

MaSh

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I did not. There's no sound from the subwoofer when I play 2-channel music from my receiver, sound comes from 2 front speakers only.

I used the same approach to test another subwoofer. There is no such issues. I believed the subwoofer can take full-frequency signal and filter out mid-to-high frequency.

When in this mode, can you check the Active channels on the receiver? Does it say that Sub is Active? The receiver display should show the active channels highlighted.

I tried different song but did not try the pre-subwoofer out from the receiver. When I played 2-channel songs, sound comes out ONLY from the 2 front speakers, no sound comes out from the subwoofer.

I tried another subwoofer which did not have similar problem.

I guess there is filter inside subwoofer to filter out mid-high frequency. I guess there is only low frequency signal from pre-subwoofer output of receiver.

Which is this another Sub Woofer? Also, please connect the Sub to the receiver's Sub Out and test.

MaSh
 

wang

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When in this mode, can you check the Active channels on the receiver? Does it say that Sub is Active? The receiver display should show the active channels highlighted.



Which is this another Sub Woofer? Also, please connect the Sub to the receiver's Sub Out and test.

MaSh

the receiver showed only two channels input. Only two front speakers has sound. I am using Pineer VSX-922 receiver.

I would like to use the pre-out to test if there is sound from that.

Another Subwoofer is JBL Digital 160. Pretty old one.
 

MaSh

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the receiver showed only two channels input. Only two front speakers has sound. I am using Pineer VSX-922 receiver.

I would like to use the pre-out to test if there is sound from that.

Another Subwoofer is JBL Digital 160. Pretty old one.

So that clears it, why there is no sound. Are you missing an RCA cable? Connect the sub to the Pre Out and play a multi channel sound track. You could even switch the receiver to Multi Channel Stereo to check.

MaSh
 

tuff

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On my Yamaha 477 , If i set the Speakers to large, By default the sub-woofer is turned off, unless i turn on the bass button. it's weird , and if i set the front speakers to small, it all runs fine.
 

efernand1

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Hi

AVR settings need to be checked....subwoofer sometimes is turned off or not active....
 

wang

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So that clears it, why there is no sound. Are you missing an RCA cable? Connect the sub to the Pre Out and play a multi channel sound track. You could even switch the receiver to Multi Channel Stereo to check.

MaSh


If I set the front speaker to small, there is sound came out from the subwoofer when I connected it through pre-out. The symptom is the same. My subwoofer cable is a Monster cable so the quality shall not be any problem.

The most important thing is if the amplifier plate does 100% covered on the speaker box then the problem gone and the woofer produce solid bass without any noise.
But if the amplifier completely covered/sealed, then the noise comes back.
 

wang

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Considering its a powered sub, ideally it should be connected to a pre-out from a receiver/DAC.
I guess even the subwoofer testing sound that you are using from youtube is also supposed to be used in a similar fashion.
The signal from your mobile phone is already amplified to a certain extent considering the fact that you are not using a USB DAC connected to the phone.!
Plus, of course, signal interference to a regular RCA cable instead of a designated sub-woofer cable.

See my new update and test on page 2.
 

MaSh

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If I set the front speaker to small, there is sound came out from the subwoofer when I connected it through pre-out. The symptom is the same. My subwoofer cable is a Monster cable so the quality shall not be any problem.

The most important thing is if the amplifier plate does 100% covered on the speaker box then the problem gone and the woofer produce solid bass without any noise.
But if the amplifier completely covered/sealed, then the noise comes back.

Thats good. Keep that setting.

Could you post some pictures showing what you mean by covering and not covering. Have you checked the earthing on the power point, just to rule that out?

MaSh
 

wang

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Thats good. Keep that setting.

Could you post some pictures showing what you mean by covering and not covering. Have you checked the earthing on the power point, just to rule that out?

MaSh

I will take a pictures tonight and upload.
 

wang

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Thats good. Keep that setting.

Could you post some pictures showing what you mean by covering and not covering. Have you checked the earthing on the power point, just to rule that out?

MaSh

two pictures uploaded, hope it is clearer now.

I also tried to shake the amplifier plate but could not see anything loose.
I carefully check every components on the amplifier plate but could not see anything loose either.


After I uploaded, I found the pictures is so small. Basically if I lift the amplifier plate up a little bit (even just 1cm), the annoying noise gone, the noise is not loud but it's that kind of middle-high frequency sound.
 

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tuff

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Is it a rumbly sound like something is loose? Can you describe this 'noise' sound that you are getting?
 

wang

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Is it a rumbly sound like something is loose? Can you describe this 'noise' sound that you are getting?



It's not that kind of rumble(boom, low frequency sound) sound, it sound like that kind of friction sound, the frequency shall be mid to high.

Forgive my English, it's hard to describe the sound of noise.
 

wang

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Is it a rumbly sound like something is loose? Can you describe this 'noise' sound that you are getting?


It give me a feeling it's acoustic/sonic/sound wave problem, not electronic problem on the woofer driver or amplifier.

But I am not sure and how to fix it.
 
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