View Full Version : Viscoelastic damping material -cabinet walls- -what is your composition?

10-07-2010, 01:26 AM
Hi, my Harbeth speakers give off an unpleasant smell going out from the bass reflex port, above all when they are working.
I think that this is due to viscoelastic damping material of walls cabinet.

Is toxic the material?.
Can it give health problems?
What is your composition?

In my case, is a unbearable, my friends feel it also.

Otherwise i am very happy with my speakers, the sound is fantastic.


10-07-2010, 11:09 AM
In private emails with us we recommended that you discuss this with your dealer.

Please tell us what your dealer said about this matter.

10-07-2010, 03:16 PM
O.K., but i donīt believe that the distributor know what is the composition, .....the manufacturer, yes.

Iīve been several months with this smell,......is unbearable; and not is burned smell.

This is the first time that this happens to me.

Anybody can explain me what is this due to?- Or anybody have had this problem?


{Moderaters comment: We have used the same rubber/foam materials for over thirty years without one single comment like yours. So, you *must* discuss this with your dealer. They are responsible for happy customer relations.}

27-12-2010, 04:13 AM
I've just received my SHL5 and I also notice a strange smell from the port of one of the speakers. It has a chemical rubbery smell to it. Strange it's only coming from one of the speakers. I'm going to guess that it will dissipate over time, at least I hope so. It's not so strong that one smells it in the room only if one is up close to the speaker. I'm going to postulate that in the manufacturing process a bit more of some substance (adhesive is my best guess) was used than maybe is called for. And that once the speaker is built and bagged and boxed the out gassing has no where to go so it just percolates. If this is the case then over time it should dissipate. I'm guessing that is what happened with the OP since he hasn't commented since October.

{Moderator's comment: this was reported but either we are immune to the smell and/or some customers are extremely sensitive to it. It should dry out. It is because the very best damping is using glues that never completely cure as they are "lossy". At this time of year, the drying-out will take longer. The cabinets are paired and even though you may not detect it in one, the glues and construction are certainly common. Also, the thick sponge foam tends to hold constructional vapours. We will look at this again but the glues are basically PVA, in inert wood glue used as a main ingredient in chewing gum.}

27-12-2010, 03:51 PM
Thanks, yes that's also what I think that over time the "vapors" as you call it will dissipate. I'll report back when they do.

28-12-2010, 12:15 AM
I reported the same problem on another thread on the HUG. Now, the smell from my SHL5 is very rare. It's only there when listening at medium to high volume.


{Moderator's comment: that will be the high velocity air motion through the port.}