I purchased a pair of small Olson speakers on Ebay recently in good condition.
They sounded decent, but had a bit too much midrange for my liking so I decided to replace the tweeters.
I found a pair of EMI tweeters like these http://www.german-vintage-loudspeakers. ... weeter.htm
on Ebay and soon as they arrive I will install them.
I had used a couple pairs of EMI tweeters (newer version with smaller round magnet, but same cone material) in two pairs of Automatic Radio speakers with excellent results.
Original crossover which was a series arrangement
Modified crossover now a parallel arrangement. Sound improved some, but was still too much in the midrange and lacking in upper treble.
Modified crossover without L-pad (1/4" speaker jack mounted in hole where L-pad was mounted) given the tweeters I purchased are 4 ohms and L-pad is 8 ohms. If the speakers do not sound good as is then I will figure up a proper 6 db/octave crossover and order the parts.
The speakers are really nice even having insulation on the inside.
Drivers. The woofers have a big honking magnet on them so I figure could probably easily handle 20 watts.
The woofer surrounds look to be made of a cloth like material probably similar to what some Fisher speakers used except these are still very flexible. Do I need to treat these with anything so they don't leak air or is that not a problem with these?
It seems like the Japanese didn't know how to properly seal a speaker cabinet. I put some RTV between the speaker baffle (can be removed) and cabinet to seal it up there and once I get the speakers sounding good I am gonna use RTV on the rear cover, but it will be done in such a way that the back can be removed if needed.
These must have spent their years in a shop or other non climate controlled building as the finish looks very dry.
I used one coat of Kramer's Best Antique Improver and got these results. Finish is slightly darker than the photo shows.
Bass response of these speakers is pretty good which I suspect is due to the larger excursion these speakers are capable of. A little smaller cabinets than the Automatic Radio speakers I have, but the Olsons have a little bit better bass response.
EDIT: I got the tweeters installed and played around with the crossover. I came up with this.
Here's the crossover board.