Strange sound from one speaker at 180Hz

M

Michael L

Audiophyte
Hey, I was doing a frequency sweep from 130Hz to 225Hz and between 180Hz and 170Hz my right speaker started making a strange sound like it was breaking up or static. It was just in that range and was fine outside that range. I unplugged the right speaker and just did the sweep though the left with no problems and when I plugged the right back in it came back. Any ideas on what it could be? crossover? woofer?
 
everettT

everettT

Audioholic Ninja
What is the source of the test tone? Did you swap the left to the right ?
 
M

Michael L

Audiophyte
It was a sweep tone made and downloaded at AudioCheck dot net. I made and downloaded it from their Sweep Tone Generator. No I did not swap the speakers but thats a good idea to try to eliminate other possibilities.
 
everettT

everettT

Audioholic Ninja
It was a sweep tone made and downloaded at AudioCheck dot net. I made and downloaded it from their Sweep Tone Generator. No I did not swap the speakers but thats a good idea to try to eliminate other possibilities.
It's possible the file is corrupted also.
 
M

Michael L

Audiophyte
It's possible the file is corrupted also.
I swapped the left and right speaker and ran the sweep again and everything was fine. I first heard the issue when I was listening to Stereo Review & Chesky Records: Gold Stereo And Set-Up and in the "Shake, Rattle & Roll" test it did a sweep with a voice telling you the Hz and when it got to 180Hz I heard it so I then wet to AudioCheck and made a sweep from 130Hz to 225HZ and heard it there too. Anyway it's gone now but I'm still not sure what could have caused the issue in the first place, any ideas?
 
Dale Doback

Dale Doback

Junior Audioholic
Hey, every so often I run into something, and fix it. Most of the time, anymore, I don't know what the cause was. I have begrudgingly learned to just be happy and take my Sherlock Holmes hat off. These systems have become very complex and I'm gettin old. Rock on...

Oh, I forgot to mention, I recently had an issue with a (downloaded) test tone. Was frantic for a minute or 2. Then realized it was the test tone. Funny how we tend to immediately think the worst. :eek:
 
lovinthehd

lovinthehd

Audioholic Jedi
Could have been something in your room being vibrated, or something in the way of a resonance due to the speaker's positioning....hard to know without more analysis on your part. Doesn't sound like an issue with the speaker itself...
 
tyhjaarpa

tyhjaarpa

Audioholic Field Marshall
I would say it might of been bad connection with speaker wire, when you moved the speaker you connected again and it is fine now.
 
KEW

KEW

Audioholic Overlord
I would say it might of been bad connection with speaker wire, when you moved the speaker you connected again and it is fine now.
That is what I was thinking that one of your speaker connections was loose and it just happens that 180Hz was the right frequency to make and break the connection. When you plugged it in later, the connection became sound.
You'll never know for sure, but that is a plausible scenario that makes some sense, so go with it and be happy!
Of course your next post will add info to refute this as a possibility, LOL!
 
Johnny2Bad

Johnny2Bad

Audioholic Chief
There is a remote possibility that the voice coil of the woofer on that speaker is slightly burnt. Maybe one coil of wire at the end of excursion is off the coil former, for example.

Running the sweep may have heated the coil when the lower frequencies were run just enough to get the aberration at 180 Hz.

Running the sweep a second time may have happened after the VC had time to cool.

As I said it's an extremely remote possibility (because it did not show up at other low frequencies). You will know, because it (or "something") will come back if that's the case; voice coil damage is cumulative. So run them as you normally would, and sooner or later it will either come back, possibly get worse, or if nothing is wrong, you won't hear anything unusual again.

You also might want to pop the covers (if they're not off now) and have a close look at the woofer dust cap. Sometimes the glue can degrade over time and it will become loose or offset. It's easily repairable if that's the case. I've seen it happen (once). It's a simple repair (re-glue it). It caused a noise at higher sound pressure levels on certain program material that sounded like a burnt voice coil, but wasn't.

It's also a little curious because 180 Hz is a harmonic of North American 60Hz AC frequency, so there is almost always some noise at that frequency, and although it should be well down in level, it's typically measurable. So it could suggest an issue with the power supply filtering (anytime you have capacitors, age or failure is a possibility). Again, another remote possibility, and one that will come back sooner or later if that's the case.

Finally, especially with any digital file, you can never rule out a momentary failure to properly play the file, in that case it would simply be coincidental that it happened at 180Hz.
 
Last edited:
everettT

everettT

Audioholic Ninja
I swapped the left and right speaker and ran the sweep again and everything was fine. I first heard the issue when I was listening to Stereo Review & Chesky Records: Gold Stereo And Set-Up and in the "Shake, Rattle & Roll" test it did a sweep with a voice telling you the Hz and when it got to 180Hz I heard it so I then wet to AudioCheck and made a sweep from 130Hz to 225HZ and heard it there too. Anyway it's gone now but I'm still not sure what could have caused the issue in the first place, any ideas?
Still could be a corrupted file. Was there an included md5 checksum to verify?
Silver lining is that if your like most gearheads, you can turn this into an opportunity to purchase new speakers just because :eek:
 
O

okay.see

Audioholic Intern
There is a remote possibility that the voice coil of the woofer on that speaker is slightly burnt. Maybe one coil of wire at the end of excursion is off the coil former, for example.

Running the sweep may have heated the coil when the lower frequencies were run just enough to get the aberration at 180 Hz.

Running the sweep a second time may have happened after the VC had time to cool.

As I said it's an extremely remote possibility (because it did not show up at other low frequencies). You will know, because it (or "something") will come back if that's the case; voice coil damage is cumulative. So run them as you normally would, and sooner or later it will either come back, possibly get worse, or if nothing is wrong, you won't hear anything unusual again.

You also might want to pop the covers (if they're not off now) and have a close look at the woofer dust cap. Sometimes the glue can degrade over time and it will become loose or offset. It's easily repairable if that's the case. I've seen it happen (once). It's a simple repair (re-glue it). It caused a noise at higher sound pressure levels on certain program material that sounded like a burnt voice coil, but wasn't.

It's also a little curious because 180 Hz is a harmonic of North American 60Hz AC frequency, so there is almost always some noise at that frequency, and although it should be well down in level, it's typically measurable. So it could suggest an issue with the power supply filtering (anytime you have capacitors, age or failure is a possibility). Again, another remote possibility, and one that will come back sooner or later if that's the case.

Finally, especially with any digital file, you can never rule out a momentary failure to properly play the file, in that case it would simply be coincidental that it happened at 180Hz.
How do voice coils get damaged? I have a weird problem where I get a vibration out of one woofer at only certain low frequencies (not sure exactly since I have not measured but upright bass tends to happen on certain notes with upright bass). Easy repair?
 
everettT

everettT

Audioholic Ninja
How do voice coils get damaged? I have a weird problem where I get a vibration out of one woofer at only certain low frequencies (not sure exactly since I have not measured but upright bass tends to happen on certain notes with upright bass). Easy repair?
What speakers? Has it started all started sudden? As stated not a likely a voice coil issue so I'd look elsewhere firat for the culprit.
 
ryanosaur

ryanosaur

Audioholic Overlord
How do voice coils get damaged? I have a weird problem where I get a vibration out of one woofer at only certain low frequencies (not sure exactly since I have not measured but upright bass tends to happen on certain notes with upright bass). Easy repair?
Something wierd that happened to me was one of the screws holding the woofer to the cabinet had loosened. I only heard it sporadically... frequency dependent. Just check and make certain all your mounting screws are tightened properly. If the problem persists... a deeper dive may be necessary, but not likely due to the VC.
 
TLS Guy

TLS Guy

Seriously, I have no life.
How do voice coils get damaged? I have a weird problem where I get a vibration out of one woofer at only certain low frequencies (not sure exactly since I have not measured but upright bass tends to happen on certain notes with upright bass). Easy repair?
What speaker are we talking about? Speakers are usually damaged by over driving. Various things can happen. It can be over excursion, where the voice coil becomes damaged as it leaves the gap and goes back in. Heat in the voice coil from over driving can cause voice coil turns to unravel and cause problems like you describe. Voice coils can also get burnt out, and either fail completely, or partially short causing lowered impedance and loss of output.

Foam surrounds can rot with age, but that is visible on inspection. I assume you have looked at the drivers for signs of damage/age.

There is no easy repair. The easiest is replacing a rotted foam surround if the surround is foam.

All other repairs require complete re-coning, if a re-coning kit is available for that speaker. A re-coning kit is a completer voice coil, suspension, cone surround and dust cap. Otherwise, the driver must be replaced by an identical driver. If neither are available then that speaker is ruined and not able to be repaired.
 
O

okay.see

Audioholic Intern
Something wierd that happened to me was one of the screws holding the woofer to the cabinet had loosened. I only heard it sporadically... frequency dependent. Just check and make certain all your mounting screws are tightened properly. If the problem persists... a deeper dive may be necessary, but not likely due to the VC.
Just checked the mounting screws. They were nice and tight the whole time. Everything sounds good except with certain moments on some tracks.
 
O

okay.see

Audioholic Intern
What speaker are we talking about? Speakers are usually damaged by over driving. Various things can happen. It can be over excursion, where the voice coil becomes damaged as it leaves the gap and goes back in. Heat in the voice coil from over driving can cause voice coil turns to unravel and cause problems like you describe. Voice coils can also get burnt out, and either fail completely, or partially short causing lowered impedance and loss of output.

Foam surrounds can rot with age, but that is visible on inspection. I assume you have looked at the drivers for signs of damage/age.

There is no easy repair. The easiest is replacing a rotted foam surround if the surround is foam.

All other repairs require complete re-coning, if a re-coning kit is available for that speaker. A re-coning kit is a completer voice coil, suspension, cone surround and dust cap. Otherwise, the driver must be replaced by an identical driver. If neither are available then that speaker is ruined and not able to be repaired.
That's really helpful. Foam surrounds are definitely intact. Cone looks really good. very good condition. I haven't pulled it out of the enclosure yet and don't even know what to look for if I did. Thanks again.
 
ryanosaur

ryanosaur

Audioholic Overlord
Also on the less extreme side is the possibility of an internal wire or lead vibrating at a certain frequency. I've heard of the leads vibrating against the Spider before...
Also in a DIY mod I did, I had an internal wire that was not battened down properly and which vibrated against the port tube at a certain frequency.
 
TLS Guy

TLS Guy

Seriously, I have no life.
That's really helpful. Foam surrounds are definitely intact. Cone looks really good. very good condition. I haven't pulled it out of the enclosure yet and don't even know what to look for if I did. Thanks again.
What speakers do you have? I suspect that the VC is coming away from the cone, or you have early unravelling of the VC. It sounds as if the driver needs re-coning most likely. It is really important to know what these speakers are.
 

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