“Screen wobble” ~ as a result of not using / having that original back metal shroud to shield the monitor?
Turns out that the two other sets of size-comparable speakers here are 16Ω. D-rats!
I checked the Peerless replacements out but found these Dayton CE30P-4 speakers instead that I’d like to try. BUT they’re not currently available in the U.S. until December. Those of you in the U.K. (and possibly elsewhere) can get them from WallofSound.co.uk for £4.99 each (SKU #848791000355). Wall of Sound does not ship to the U.S. - but… any core member (Philgood?) from the U.K care to pick up a pair and ship ‘em over here? I’d PayPal you the costs in advance. (PM me.)


Finally got the “bubbles” removed
and the speakers. (Wonder which group of brainiacs
designed them and chose the foam-surround speakers… Harmon Kardon or Apple?)
Speakers might have lasted longer if no silicone was used to seal enclosures.

Red dots and arrow denote areas where hot glue will go to re-seal the enclosures. Blue arrow notes plastic “clip” that’s very difficult to disengage for removal of the bubbles from the iMac chassis. I used a very long & thin screwdriver to press this clip / tab down from the mounting to carefully release the bubbles. (Lawrence Welk Show, anyone?)
I do like the overall design of the speaker enclosures - but whoever decided to seal the two halves of the bubbles with silicone, didn’t really do the early iMacs any favors. Silicone (as it cures) “gasses off” releasing acrid fumes that most likely attacked / interacted with and broke down the foam surrounds of the speakers over time… eventually turning the foam surrounds into sticky goo. Especially because the speakers were enclosed in the bubbles and could not vent the fumes via the small sound ports of both speaker enclosures. The gasses likely permeated, attacked & broke down the porous foam speaker surrounds from the inside.
After cleaning all of that goo (and 99% of the silicone from around the bubbles) the small speakers harvested from an early G5 iMac fit perfectly into the bubbles w/o spacers. *Only problem is that these speakers and the Sony SRS speakers are 16Ω - which means that they may be a much-much lower volume installed in a system designed for 4Ω speakers.
I’ll use hot glue to anchor the new speakers in place - AND to seal the bubbles back up. This might make it difficult to ever again replace the speakers… but sans the silicone, might never need replacing for another 20 years? Interesting how Apple later changed from the foam-surround G3 iMac speakers to the butyl rubber surrounds of the G4 & G5 speakers? Wonder why? You can see the surround rot of the original speakers in the above image.
https://imageserv5.team-logic.com/mediaLibrary/99/Outgassing_20of_20Silicone_20Elastomers.pdf“Ventilation is a necessary part of the post-cure process. Figure 8 compares well ventilated samples to samples sealed in aluminum foil. It is immediately obvious that the sealed samples do not “breathe” and volatiles are trapped within the rubber. (After 15 minutes the ventilated samples have lost more volatiles than 5 hours for the sealed samples.) All of the sealed samples showed evidence of reversion (i.e., rubber degradation). If rubber ‘breathing’ is prevented the post-cure process is ineffective and may lead to excessive service outgassing and ‘smoking’.“Will now attempt to remove the back metal shroud from the old speakers to possibly use on any new speakers for shielding. Have tried to pry them from the magnet but no luck. Really strong magnets… but I think they’re also glued. Next, I’ll attempt to torch them in order to burn away any glue. Also wondering about the shield-ability of encasing magnet backs with a thick layer of hot glue… which also might fill the gap for any new speaker depth deficiencies in the bubble.
Why all of this bother for an old G3 iMac?
I too remember just how good the originals sounded way-back-when.
Hopefully all of this will eventually produce similar (and longer-lasting) sonic results?
And for now I’ve yet ANOTHER project awaiting parts.
UPDATE: Emailed Wall of Sound (U.K.) late today about other possible alternatives and then discovered that the CE30P-4 speakers are made by Dayton Audio in Springboro Ohio (U.S.). So now I’ll give them a call on Monday. In the meantime, there’s one listed on eBay and one available in the Netherlands.