[Jerrin]

I have a pair of LS6's that I just bought and hooked up.  During a preview in a movie (it had some pretty heavy bass, but not an explosion) I heard something that sounded like chirping or maybe a cricket.  I'm going to take a look at the woofers and see if I see anything that is obviously bad.

I didn't hear the problem until I played at moderate volume (probably 80 or so Dbl).  At lower volumes I never heard the problem.

Any other ideas?  What does this sound like?   What should I be looking for?

[Big Red Machine]

How much power do you have in the amp?  Perhaps it clipped or you maxed out a woofer excursion?

[avahifi]

You were probably hearing either a voice coil bottoming out or rubbing in its gap.

Either noise can mean doom for your speakers if you duplicate the conditions that generated the signal that caused this.

The issue could be caused with a much underpowered amplifier for the speakers, or by simply overpowering them.

It also might mean there was a prior defect you have just uncovered with the speakers.

As Red said, more data would be helpful.  Amplifier power and make and model?  Speaker efficiency and impedance?

Regards,

Frank Van Alstine

[Jerrin]

Thanks guys.   I have an Onkyo 805.  The speakers are a line array and go down to around 25hz or so.   See:   http://www.stereomojo.com/LS6%20review/AV123LS6review.htm

I was running them full range, as I figured I had enough power since I was not pushing them really hard.  The chirping sound seemed to be coming more from a driver rather than the whole speaker as it was not loud, but noticable.

[richidoo]

You can gently push on each cone driver to see if any are rubbing. You will feel it in your fingertips. If you don't feel anything that doesn't mean that it won't rub under normal use, but it might reveal the culprit the easy way and save some trouble.

I assume the sound is happening more than the one time during that preview? Playback the same preview to make sure it's not on the content. If not, try to make the sound happen during radio play to exonerate the video player and Receiver. Confirm it is speaker problem by swapping speaker wires so that the right side amp powers the left speaker and versa. If the sound stays on the same side, it is definitely the speaker.

Replacing a driver is not hard, once you find which one.

[srb]

If it's not the program material (i.e. watching "Revenge of the Monster Crickets"), it may be easier to determine which driver is the problem by playing CD or downloaded test tones rather than music or movies.
 
Steve

[Jerrin]

You can gently push on each cone driver to see if any are rubbing. You will feel it in your fingertips. If you don't feel anything that doesn't mean that it won't rub under normal use, but it might reveal the culprit the easy way and save some trouble.

I assume the sound is happening more than the one time during that preview? Playback the same preview to make sure it's not on the content. If not, try to make the sound happen during radio play to exonerate the video player and Receiver. Confirm it is speaker problem by swapping speaker wires so that the right side amp powers the left speaker and versa. If the sound stays on the same side, it is definitely the speaker.

Replacing a driver is not hard, once you find which one.

I was thinking about disconnecting the speaker that had no problem and playing the material again so I could better tell what was making the sound.  Then I was going to check each woofer for signs of obvious damage.  I will also use your approach and switch the cables to see if the other speaker will make the sound.

I'm not too worried about the prospect of changing a driver out if need be.  I'm more worried about being able to identify signs of damage or something wrong.

I'll take your advice too and play some sine waves (maybe 20 HZ and up), but at a lower volume.

[avahifi]

I see that the speakers are 8 ohm impedance and 91 dB efficient.  This should be an easy load for your Onkyo.

However with so many small drivers you will need to make some of the tests others have advised above to determine if the fault is with the speakers or the amplifier and then to find out which driver is in trouble if that is the case.

Good luck.

Frank Van Alstine

[Diamond Dog]

Replacing a driver is not hard, once you find which one.

I  remember replacing the Uni-Q drivers ( not the tweeter but the midrange it fits into ) on a pair of KEF Reference 103/4 once. No fun.

D.D.

[richidoo]

It probably will not show any visible damage. The rubbing happens up inside the magnetic gap, impossible to see up there from the outside. Usually the spider blocks viewing the voice coil. A rubbing voice coil is a normal failure mode in drivers, caused by gluing the spider and/or surround to the driver frame slightly off center. Sometimes the defect is not caught in factory inspection, but appears after break in as spider loosens up.

I  remember replacing the Uni-Q drivers ( not the tweeter but the midrange it fits into ) on a pair of KEF Reference 103/4 once. No fun.

Yeah that sounds a little scary.

[smargo]

I have a pair of LS6's that I just bought and hooked up.  During a preview in a movie (it had some pretty heavy bass, but not an explosion) I heard something that sounded like chirping or maybe a cricket. 

Open the speaker up and take the bird and the cricket out - let them go outside where they belong!

[Jerrin]

You can gently push on each cone driver to see if any are rubbing. You will feel it in your fingertips. If you don't feel anything that doesn't mean that it won't rub under normal use, but it might reveal the culprit the easy way and save some trouble.

I assume the sound is happening more than the one time during that preview? Playback the same preview to make sure it's not on the content. If not, try to make the sound happen during radio play to exonerate the video player and Receiver. Confirm it is speaker problem by swapping speaker wires so that the right side amp powers the left speaker and versa. If the sound stays on the same side, it is definitely the speaker.

Replacing a driver is not hard, once you find which one.

Well, I removed the third woofer from the bottom and it had an inner port that had become disconnected and was probably just bouncing around inside.   I looked at the one above it and below it and they were fine.  So I connected it well.   I was able to give a brief listen and it sounded pretty good.

Later, I was able to give a really good listen using Joe Jackson's "Stepping Out" and I heard something that sounded kind of like distortion.  So I lowered the volume and listened at each cone.  It sounded like it was coming from the 4th from the bottom.  I then used your push test and lo and behold, the 4th from the bottom woofer made a sort of scraping/crunchy sound.  As I tested it further, it seemed the sound came from the top part of the woofer.  When I gently pushed closer to the top, I noticed resistence and it made a louder sound.

Does this show that this woofer is damaged?  None of the other woofers did this.

[avahifi]

Yes, the woofer that is making the scraping sound is indeed damaged.

One way speaker voice coils become damaged is when they are driven too hard and the voice coils get very hot.  This can actually soften the glue that holds the coil windings to their former.  A coil or two can actually spring loose from the coil and then rub in the gap against the non moving parts.  Often, after this happens for a while the loose coil strand will wear through from the rubbing contact and break or part.  Then of course there will be no more sound from that driver at all.

You will need to replace that woofer or find out if a good speaker repair service can "recone" it to identical new specifications.  This involves replacing all the moving parts in that woofer; coil, cone, spider, surround, etc.  This is sometimes advisable if the original woofer is either too expensive to replace or is no longer available.

Regards,

Frank Van Alstine

[Jerrin]

Thank you all for your advice.    It really helped.

[richidoo]

You have to press in the center otherwise you can tilt the driver cone and cause it to rub when it is actually healthy. Fixing it may not be possible, because the spider and surround are usually destroyed when removing the cone, and the mfg (Adire Audio) is defunkt so rebuild parts are not available. Changing them to 3rd party repair parts would change the driver's specs. You could also look for another LS6 to use for parts, or maybe the same driver was also used in a smaller AV123 speaker?  You might PM "Danny," (Danny Richie, GR Research) the designer of your speakers and active member on AudioCircle, maybe he can give you some good advice on possible replacement driver. Kevin Haskins, Diycable.com, is another active AudioCircle member now sells his 180mm Exodus woofer based on XBL technology, but I think it is a whole new animal.

This is the woofer description: http://www.adireaudio.com/Files/XBL2TechPaper.pdf