Refoam

[ironlake]

Is there a break in period for new foamed speakers to loosen up the foam.

[Carlspeak]

Depending on how much bass you play, it could be anywhere from a 1/2 hour to a day. The woofer's resonant frequency may drop a hz or two. You may not notice any difference.

[tysontom]

There has been a lot of discussion about "break-in" periods for speakers, either new ones or ones with new surrounds. It's as though the new rings and bearings have to "seat-in" for proper operation. Although there are probably some minor changes that do occur, the urethane-polymer foam doesn't "seat in," as such. Therefore, just by playing your speakers you will get the effect of any "break in," if there is any, but likely there would not be any real difference in the box resonance, lower distortion, etc. of the speaker from the moment the new surrounds are in place until they have been placed for several hours or years. Perhaps over a period of fifteen years, just prior to the deterioration of the new foam, there could be some very minor difference, but "break in" is (IMO) mostly an emotional thing and most likely not meaningful to loudspeaker performance.

It would be helpful if someone measured a speaker before the so-called "break-in" period and after several hours of break in (after the voice coil has cooled to normal temperatures) to see if there are any marked improvements in sound. I don't think anyone has ever quantified the effectiveness of speaker "break-in" period.

--Tom Tyson

[genek]

My own experience has been that letting the newly installed woofer sit overnight and then retorquing the screws can make a difference in the sound, but I theorize that this is mostly caused by the gasket or sealer putty compressing from the initial torquing of the bolts and letting a bit of air pass.

[ironlake]

My main experience with speakers is with model trains with wound. The 2 inch speakers we use definately get louder as they play. The whistles are quite loud and at first you set the volume wide open but after awhile you start turning the volume down, so there is definately a break with these little speakers.

They do get driven with more wattage than rated for and the little cones really vibrate when you trigger the whistle.

[tysontom]

ironlake, I wonder if what you notice on the little 2-inch PM speakers is the heating of the voice coil and thus a change in impedance. Hard to tell, but the coil will change (for one thing it will expand with heat), putting it closer to the outer edge of the magnet gap, which might increase sensitivity slightly. Usually, however, a heated voice coil will do the opposite, causing a rise in impedance and loss of output. In the little 2-inch PM speaker, the heat may be causing the coil to partially short, thus lowering the impedance and increasing output and distortion. Those little PM speakers also have a corrugated surround formed from the speaker's paper material, so maybe buzzing back and forth excessively causes it to "loosen up," as it were.

--Tom Tyson

[michiganpat]

anecdotally, it seems like after a while new foams feel much softer in a "push test" of pushing on the half roll a while after the speaker is cycled and used, where the foam has been repeatedly flexed. dunno if it is enough to change driver specs appreciably, though

[dynaco_dan]

Hi there

I do hope that you are fusing the 2" driver. LOL

[ironlake]

no fuse, they are tough little things and have not burned one out yet. When they distort they sound terrible, so you turn them down until they sound good.

Also I refoamed the two advent heritage woofers in one of my advents as I did not put on the simply speakers foam life extender soon enough. The other one got the restorer about a month earlier and they are still fine. The used ones have a very soft push compared to the new foam on the other pair of speakers but the woofers sound the same and put out the same amt of bass according to my radio shack meter at one foot distance to meter. Bass is a 40 hz tone from a test cd.

My ar 3as woofers feel the same way. The one woofer has orignal cloth suspension and the other has been refoamed and the cloth seems very soft compared to the new foam. The cones are identical original type with the extra foam ring in the center of woofer.

[RoyC]

no fuse, they are tough little things and have not burned one out yet. When they distort they sound terrible, so you turn them down until they sound good.

Also I refoamed the two advent heritage woofers in one of my advents as I did not put on the simply speakers foam life extender soon enough. The other one got the restorer about a month earlier and they are still fine. The used ones have a very soft push compared to the new foam on the other pair of speakers but the woofers sound the same and put out the same amt of bass according to my radio shack meter at one foot distance to meter. Bass is a 40 hz tone from a test cd.

My ar 3as woofers feel the same way. The one woofer has orignal cloth suspension and the other has been refoamed and the cloth seems very soft compared to the new foam. The cones are identical original type with the extra foam ring in the center of woofer.

ironlake,

If you applied "Foamguard" to the AR-3a foam, it will feel stiffer than the cloth surround, AND performance will have been compromised. It is a white glue compound, and it stiffens the foam when it dries. Modern foam surrounds do not need to be treated.

Another thought...I believe Simply Speakers' 3a foam replacment has a 1/2" roll, which is somewhat stiffer than the more desirable (and more common) 5/8" roll version.

Roy

[ironlake]

no foamguard on the 3a woofers just the old advents and they stayed quite soft. The replacement roll on the 3a is 5/8 wide, but I would like to change to a cloth suspension woofer which I presently negoating with a guy. I feel the bass is stronger out of my cloth woofer than the refoamed one. anyone else feet that way?

[dynaco_dan]

no foamguard on the 3a woofers just the old advents and they stayed quite soft. The replacement roll on the 3a is 5/8 wide, but I would like to change to a cloth suspension woofer which I presently negoating with a guy. I feel the bass is stronger out of my cloth woofer than the refoamed one. anyone else feet that way?

Hi there

Interesting question which I have commented about before.

Myself, I would prefer the cloth surround for longevity.

Others may prefer the foam surround.

There may be a power handling and frequency response difference in favour of the foam/ceramic magnet woofer rather than the cloth/alnico magnet woofer.

In reality, who will notice any difference, sight unseen?

I am not happy that no manufacturer is reverting to rubber/cloth/neoprene etc instead of foam.

Of course I do know that the foam rot will always create new sales for speakers, kits or just replacement drivers.

If I hold my breath until a manufacturer does this, I will be long gone.

Longevity does not make more money, today, and that is all that business is, making money.

There is nothing wrong with making money but facing a driver refoam every 10 or so years is a tickoff, to me at least.

[ironlake]

If I play the 30 hz voice coil alignment cd that came with the foam upgrade on the ar3 the speaker with the cloth surround moves back and forth more than the foam one and has 1 or 2 db more of output than the foam one does. I get a reading of 95 db on the cloth woofer and 93 db on the foam. Both taken at one yard away. That is why I am wondering if the foam needs to go back and forth more to loosen up.

[RoyC]

If I play the 30 hz voice coil alignment cd that came with the foam upgrade on the ar3 the speaker with the cloth surround moves back and forth more than the foam one and has 1 or 2 db more of output than the foam one does. I get a reading of 95 db on the cloth woofer and 93 db on the foam. Both taken at one yard away. That is why I am wondering if the foam needs to go back and forth more to loosen up.

The 5/8" roll replacement foam is very compliant, and does the job from the start. It won't change significantly over time. I have re-foamed, re-built, and measured many of these woofers, and do not believe the cloth surround woofer provides "more" bass response as a general rule. There are, however, some response differences between the cloth surround/alnico magnet version, and the the foam surround/ceramic magnet version of this woofer...AND there are differences between various iterations of the foam surround version .

The spider is a vital component of the suspension system, and is just as important as the surround when discussing compliance. The AR spider was changed a number of times over the years, and accounts for most of the deep bass differences I have measured. It was made progressively stiffer over time. Measurement software such as the Woofer Tester 2 and 3 series will reveal differences, as well as show how added materials are affecting performance. (this software is what I used to verify "Foamguard" degrades performance.) Pushing on the surround will tell you very little.

Also keep in mind, the 3a woofer crossover inductor must match the generation of woofer you are using.

These are old drivers, and it is not uncommon to find response differences due to wear of components such as spiders and cloth surrounds. I have found woofers of the same generation to have response variations as well.

Roy