Quasar! From Motorola...
... or so the old TV ads go.
I couldn't readily find a picture of these speakers, so If you have one (or two) please post so I can get an idea of what to look for.
I'm a fan and amateur vintage loudspeaker picker, so I'd be happy to scour my local area flea markets, craigslist, etc. to help you find what you're looking for.
In the meantime, do a google search for "<speaker model number> craigslist" and sometimes you never know what you may find.
If I recall correctly, Quasar was a Motorola corp., so those speakers may be high-quality. If they sound great to you, go after them!!!