Are loudspeakers affercted by heat?

[dave2010]

Just playing a CD bought after a piano recital the other day, and noticed a distinct rattle on the RH speaker. Sometimes one hears this kind of noise on a piano in a concert, but having just swapped the leads over it seems to stay with the RH speaker. Good news is that probably the CD is excellent - the bad news is that I may now have to deal with the speaker. It might have been affected by heat over the summer. Is that a definite possibility?

Rattling sounds from speakers can presumably come from all sorts of things, and not even necessarily on or in the speaker (e.g nearby ornaments), but assuming the speaker has a problem, what would give rise to the sort of rattles - loose speaker windings perhaps? Poor speaker suspension? Damaged tweater? I've discounted grilles, because I've taken any such "protection" off.

The pianist on the CD is Alexai Grynyuk - outstanding - and this is the CD - probably also excellent - http://www.orchidclassics.com/releases/liszt-works-for-piano-alexei-grynyuk/

[Wakefield Turntables]

Dave,

My big ATC's sit in direct sunlight 12-15hours a day during summer and have done for the last 2-3 years with no issues.

andy

[Spectral Morn]

If the drive units were exposed to direct sunlight through glass maybe, excess heat might lead to glue failure. Car speakers are designed for temperature extremes domestic ones less so.

I would as a first thing check all the fixing screws. bolts etc are tight - do not over tighten. Then pick the speaker up and give it a shake to see if something has come lose. Crossovers are sometimes glued in place and the glue can fail. Access is usually via where the binding posts are but much depends on the make, as sometimes one has to remove a drive unit to get access.

I would also very gently push the bass and mid drivers in and out, listen for any rubbing, unevenness in movement or sticking. Don't push by much just gently.

However if these are still in warranty take them back to the dealer.

What speakers are they?


Regards Neil

[walpurgis]

It could be a sagged bass driver suspension. Remounting the bass unit (bass units?) turned 180 degrees can often sort this, as the coil/cone weight is then applying a load in the opposite direction.

[Paul Lange]

It is possible if the speaker has been in direct sunlight but I suspect the effect would be either sustained high temperatures or UV causing a breakdown of any rubber or plastic components. This would most likely be visible. I think maybe a screw or other fixing has worked loose, maybe, if you're unlucky the cone suspension has given out and a voice coil is contacting the magnet on a driver. I think Dalek's advice is sound but just remember don't push on the dust covers too hard or you might dent them.

[Spectral Morn]

It is possible if the speaker has been in direct sunlight but I suspect the effect would be either sustained high temperatures or UV causing a breakdown of any rubber or plastic components. This would most likely be visible. I think maybe a screw or other fixing has worked loose, maybe, if you're unlucky the cone suspension has given out and a voice coil is contacting the magnet on a driver. I think Dalek's advice is sound but just remember don't push on the dust covers too hard or you might dent them.

Good point, I assumed a level of knowledge which might be absent so NB only push the actual drive unit not the centre bit or the surround. Put your hands on the left and right side of the drive unit and very gently press in a smidge then out, but evenly.

But if in warranty don't do anything, but pack them up take back to the dealer, with the music and let them do all of this.


Regards Neil

[dave2010]

Thanks guys for the comments so far. I'll be back in a while with more info/details.

It is possible that these speakers got up to 50 degrees C - would almost certainly have hit 35 degrees, so some of the suggestions about melted glue and plastic may be on the right lines, sadly. A plastic TV stand in the same area now lurches forward by about 10-20 degrees, and I'm trying to get it to lean the other way now.

No warranties - well out of date, but these things were working quite well until very recently.

[YNWaN]

1/ a crossover component come loose and is rattling - these are often fixed down with hot melt glue and coils can themselves get hot - coupled with a high ambient temperature this could have made it come loose (just glue it back in place).

2/ the drive unit may need to be tightened up in the cabinet (woofer or tweeter - or both).

3/ the internal wires connecting the drivers to the crossover could be touching something (unlikely but not impossible).

4/ the speaker is vibrating against the floor or stand because it isn't quite adjusted correctly.

5/ something in the room, near the speaker, is vibrating enthusiastically - mirror, picture, window, ornament etc. (this is common).

6/ the cone is coming away from the roll surround/ the roll surround is coming away from the basket. Foam roll surrounds have a very definite finite life and rot away over time - they definitely need replacing eventually (heat and light exposure speeds this process up).

7/ the voice coil wire has started to delaminate from the voice coil former - probably not directly related to the rooms temperature as such. You can't see if this is happening as it is hidden inside the drive unit but swept tones will reveal it - usually a strong buzzing on some notes at higher volume levels. The only cure for this is to have the drive unit repaired or replaced (replaced is better IMO).

8/ it could be the voice cone sagging but it's not that common in my experience - has to be a larger driver with a heavier cone. The cure is simply to invert the driver which is easy enough to do.

[walpurgis]

it could be the voice cone sagging but it's not that common in my experience - has to be a larger driver with a heavier cone. The cure is simply to invert the driver which is easy enough to do.

Funnily enough, I've come across three pairs of speakers with this problem in the last year or so. Two pairs were Tannoys with the plastic coned DU series drivers. Coils were rubbing and when the cones were moved back and forth with a little upward pressure the rubbing stopped. Clearly sagged!

[fatmarley]

I had a rattle on a speaker years ago and when I opened it up I found the port was glued to the inside wall of the enclosure. The glue had failed and the plastic port was vibrating against the side wall.