FS RCA 9458 compression drivers with NOS diaphragms

For Sale
1) Pair of RCA 9458 3” phenolic/1.4” exit compression drivers with pair of NOS/uninstalled diaphragms.

For sale is a pair of RCA 9458 alnico compression drivers / speaker units with very rare,original, new old stock phenolic diaphragms.

By way of background, the RCA 9000 series drivers began with the MI-9443 field coil unit in 1940, and was replaced by the 9448 permanent magnet model after the war. The 9458 came next (possibly early to mid-1950s), then the 9548 in several versions extending into the 60s/70s. Some of the diaphragms in these drivers had a flat compliance, though most used a half roll compliance. Like the early 1400 series field coil units,these fine drivers have been inexplicably undervalued and ignored by collectors and DIYers until fairly recently.

These have the pepper-pot phase plugs. On the right horn, good from circa 300 Hz to 6K. Would be perfect on a large horn (e.g. 1503/5) with tweeter added on top.

This pair are UK badged and says made it in the UK, but I find that hard to believe. In excellent cosmetic condition (see pics).

These 9458 drivers have serial numbers: 87667 and 89136.

The original, NOS phenolic diaphragms (with half-roll compliance) both come with original boxes, are both stamped “172607/501” and have serial numbers: 323 and 1044. They measure very closely at 8.5 ohms and 8.6 ohms installed.

Out of sheer curiosity, I installed the diaphragms (87667 with diaphragm # 323 and 89136 with diaphragm # 1044) and swept each driver from 20Hz to 20khz (at low volume) and both sounded fine all the way up with no buzzes, scrapes etc.

I also tested each with music (again at low volumes) and each sound very sweet indeed.

Happy to share vid of them playing.

Will be shipped with diaphragms installed to minimise potential for damage.

Asking €2200 OVNO + shipping from Dublin, Ireland. Payment via bank transfer.




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Update: finally got to test the Altec 23691/414's and sound lovely. No buzzing or scraping. Happy to shoot through vids of working units.
Bump - update on RCA 9458 drivers. Tested and sound bloody lovely! Get yourself a nice piece of American/English cinema history.