Loudspeaker driver rubber sourround lifetime

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Defender
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Loudspeaker driver rubber sourround lifetime

Post by Defender »

Hi all,

I have a question if someone has experience with the expected lifetime of a drivers rubber surround (assuming no bad conditions like exposing the drivers to direct sunlight).
Is there something you can do to care?

I am not talking about the foam surrounds which some drivers have as they seem to have a shorter lifetime than rubber - at least that is my experience.
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Re: Loudspeaker driver rubber sourround lifetime

Post by sunbeamgls »

Older foam surrounds do disintegrate but they're supposed to be better on newer speakers.
I have seen, in the last 10 years, several pairs of the original Mission 770s where the 'rubber' has gone brittle and cracked. However I've seen lots of similar age and older speakers (eg a pair of Heybrook HB3s I have at the moment) where the 'rubber' is fine.
I used the inverted commas here as I am referring to what lools like rubber but could be something synthetic or blended.
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ThomasOK
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Re: Loudspeaker driver rubber sourround lifetime

Post by ThomasOK »

As sunbeamgls suggests, there is no hard and fast rule as to how long rubber (or rubber appearing) surrounds can last. It all depends on the quality of material they use. I have Linn Isobariks I bought in 1988 and another pair that were built in 1992 that I acquired a few years ago. The surrounds on all the midrange and bass drivers are perfect and the tweeters are fine on the 1992 set as well. (I replaced the ones on the 1988 pair with later Linn SPKR 038/2 tweeters, but they were still working fine when I did this.) Those bass and midrange drivers were made by KEF and I have seen numerous other Isobariks and KEF speakers dating to the mid 70s that are still working fine. Also the surrounds are still fine on several Spendor speakers I have seen of the 70s which used their own midrange and bass drivers, like the BC1. However, the spiders on these tend to sag after a while and the voice coil can rub, but taking the driver out and rotating it 180 degrees and remounting it usually fixes this.

On the other hand the surrounds on my ATC 100ASL speakers failed after about 10 years, first on one speaker, then a couple of years later on the other. At first I thought they must be foam for that to happen but I confirmed with ATC that they were rubber. They did seem to be thinner than normal rubber and they may have suffered from the loud playing of a speaker killing CD I have with very powerful, low bass. I have also seen a number of Dahlquist DQ10s from the 70s with cracked surrounds on the Philips midranges they used. The bass drivers they used were made by Advent and had foam surrounds so those are probably ready for their second (or third) refoaming by now. So some can last for many decades, but not all.

On the other hand, I am currently listening to a pair of Quad ESLs which are operating with their original panels and crossovers and are 60 years old! They are the ones in the latest clip I posted under My system. They did have the paired series 1kv diodes replaced with the 3kv single ones Quad switched to later because they are more reliable, but the rest of the power supplies are also original. They will soon be replaced with my other pair that are undergoing a full rebuild in the hopes they will last another 60 years with even better performance.
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Defender
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Re: Loudspeaker driver rubber sourround lifetime

Post by Defender »

thank you for all your comments - I am always impressed how some companies are building things to last (Quad)

I was asking because my midrange drivers have rubber surrounds which feel a bit stiff after 15years.
They are french Audax chassis.
There are two things which are discussed to take care of rubber:
one is talkum/talc? and the other one is silicon oil in small amounts but at least silicon oil can change the structure of the rubber or influence the glue so not really recommended for use.

did anyone tried to somehow take care of your rubber surroundings?
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