Vintage Henry Kloss Advent Loudspeakers

IMO, they were one of the best examples of the '70s "New England" sound which leaned toward neutral, as opposed to the "West Coast" rock & roll party school of design.
Back in 1974, I purchased a pair of the Smaller Advents for around $74 each from Wall-to-Wall Sound.
Something about the "neutral" sound, yet the seductive quality of what they produced kept me content for a long time.
And my 20-something ears determined that they were the right choice, among dozens of other brands.
By 1986, the woofer surrounds dryrotted, and I lost them, moving on.
But a recent audition of a set of restored Advents that someone was selling brought back that "goosebumps" feeling.

My neighbor has a restored set of the Larger Advents - and all I gotta say is... wow, that sound!
 
  • Like
Reactions: CliffR52 and jkasch
I would leave the crossovers alone. If something is seriously wrong with the crossover or drivers I would do nothing at all. However, if they are working…

Depending on the condition of the veneer, I would consider anything from sanding (most work) or stripping and refinishing them (more work), using Howard’s Restore-a-Finish (less work) or simply reconditioning them using Howard’s Feed-N-Wax (least work).
 
I would leave the crossovers alone. If something is seriously wrong with the crossover or drivers I would do nothing at all. However, if they are working…

Depending on the condition of the veneer, I would consider anything from sanding (most work) or stripping and refinishing them (more work), using Howard’s Restore-a-Finish (less work) or simply reconditioning them using Howard’s Feed-N-Wax (least work).
Good advice.
I won't touch the crossovers unless it's necessary.

The cabinets look like they originally had a wrap which has been peeled off.
I'm into restoring natural timbers, but mdf doesn't seem a good look to preserve.
I'll do it if I decide to keep things totally standard for collectors, but walnut vinyl wrap could be an option as this was an original standard option and will make them more appealing in someones living room.

What are your thoughts?
 
Hi.
With a few minutes of "spare time" (very rare for me), I removed one of the Advent woofers.
I've deduced (to my horror) that a previous owner had replaced the surrounds with rubber ones.
Further, to save the circular masonite pieces glued around the face of the baskets, they glued the surround to the rear of the3 basket perimeter.
I'm in the process of removing the surrounds and replacing them with foam.
How should I go about softening the bond between the surround and the cone?
Also the circular masonite pieces are blemished and inhibit the correct fitment of the replacement surrounds.
The masonite pieces are firmly glued in position and can only be removed by destroying them.
I was hoping to keep the face of the speakers with original authentic look.
Will removing the masonite affect their value?
I don't think I have the correct tools to create replacements!
thanks cliff
 

Attachments

  • Advent Loudspeaker 4.jpg
    Advent Loudspeaker 4.jpg
    432.4 KB · Views: 127
Hi.

I've deduced (to my horror) that a previous owner had replaced the surrounds with rubber ones.

I'm in the process of removing the surrounds and replacing them with foam.

I was hoping to keep the face of the speakers with original authentic look.
Will removing the masonite affect their value?

thanks cliff
How did they sound initially?
If they sounded good, performed well, I'd leave well enough alone.

The previous owner likely used rubber surrounds to upgrade and insure long-lasting woofer life.
Going back to foam is like going back to sure trouble.

While Advents, particularly the original Kloss Era, are coveted and adored, they are speakers, not some rare gem-stones from an Egyptian tomb, and this human conception of worth is basically just utter greed.

I have recently heard a set of Original Large Advents re-surrounded with the long-lasting rubber, and they sound just like they did when I purchased my own Advents back in the mid-1970's.
And they costed a reasonable $200 for the pair.
 
  • Like
Reactions: Galu
I have recently heard a set of Original Large Advents re-surrounded with the long-lasting rubber, and they sound just like they did when I purchased my own Advents back in the mid-1970's.
Thanks W.
Did you compare their performance from memory?
Subjects like these are very confusing to people like me.

My understanding was that rubber surrounds are good for P.A. and basic stereos where longevity and keeping a lid on costs are desirable, and that foam may not last as long but is better suited to hifi.

This is a quote from an experienced speaker repairer on this subject: "I'm an old speaker guy and can tell you that ANY speaker recone is a guess in a sense. If you have ever re-coned many speakers, you may notice that you get one surround and it is thin and wimpy, you get another and it is thick and stiff. Anytime you change the mechanical ease or difficulty that allows the driver to move, you change QMS. So the trick would be to try to mimic how stiff that original surround is. The likelihood is, If you have a sealed box woofer then you could get away without much noticeable difference using a butyl surround, but be aware, YES, the woofer spec will change when changing from a foam to rubber surround. If you do change it, make sure that you re spec the woofer, the port tuning may need to be tweaked. Again, if it is sealed, the difference should be minor."

These Advents are sealed boxes so this repairers advice aligns with yours.
Did the Advents originally come with foam surrounds, or were they butyl rubber?
 
Last edited:
Originally foam, which dryrotted to a mess after about 10 years.
It's "old school" surround, I don't like speakers with that.

As for the butyl Advents, they sounded indeed like I remember them, wonderful non-fatiguing speakers.
I now own a pair of Advent Maestro floor models and always enjoy music on them.
I lay on the sofa and can listen for hours.
 
Originally foam, which dryrotted to a mess after about 10 years.
It's "old school" surround, I don't like speakers with that.

As for the butyl Advents, they sounded indeed like I remember them, wonderful non-fatiguing speakers.
I now own a pair of Advent Maestro floor models and always enjoy music on them.
I lay on the sofa and can listen for hours.
I've read from a number of sources that indicate that foam surrounds have improved since the early days and are now far more resistant to perishing.
Also, it's been said to keep the foam away from long periods of direct sunlight.

Although non fatiguing is good, I wouldn't like it to be at the expense of sharpness and detail.
 
The composition of the foam used in speaker surrounds may have improved in terms of resistance to UV, but for longevity you just can't beat P.V.C. surrounds.

Unlike modern speakers, your Advents may not feature highly in the "sharpness and detail" stakes regardless of the woofer surround material used in their renovation.
 
The composition of the foam used in speaker surrounds may have improved in terms of resistance to UV, but for longevity you just can't beat P.V.C. surrounds.

Unlike modern speakers, your Advents may not feature highly in the "sharpness and detail" stakes regardless of the woofer surround material used in their renovation.
Hi Galu.
I'm with you on your recommendation.
For many aesthetics can be as important as sound reproduction.
This all started with after inspecting the masonite circles which form a bridge between the surround and the basket.
They're a little knarly.
I was considering cutting out a couple of new circles.
It necessitates breaking the glue connection between the surround and basket
While at it I thought I could glue on foam replacements. It's only approx $12 extra.
As the original Advents were sold with foam it isn't this process restoring the speakers closer to original?
Is it worth it?
If yes, is it easy to remove the bond between rubber and the cone?
PS: Nice tartan.
 
Cliff, since your intended course of action carries a real risk of damage to the loudspeaker cone, I cannot wholeheartedly recommend it.

i wouldn't put too much emphasis on originality as these speakers are never going to substitute for a lottery win!

That's the best advice your Tartan Terror can offer. 😀
 
  • Like
Reactions: kevinkr and JMFahey
The compliance of a surround is an engineered feature, and can be matched, or not, in various(not to say all) materials.
I have had good results with surrounds from Midwest Spkr repair.
They will not tell you that size matching is all.

Note that the spider compliance has greater influence than the front surround, and there is little we can do about that in most cases.
 
  • Like
Reactions: Galu