Re: classic SP Horns
Date: 04-13-2012 - 17:30
Airchime Ltd. of Canada licenses their airhorn designs to Nathan.
The standard M3 and P3 had the same tuning; as did the M5 and P5. They sounded vary different due to their design differences while sounding the same chord.
The sand cast molds for the later P series horns ended up out of tolerance, resulting in the P3 and especially P5 horns being horribly out of tune. The M horn may have been the "classic SP" horn of the 50s, but I would say that the old casting P3 was was the classic SP horn of the 70s.
Most new locomotive horns now seem to be a variation of the Nathan/Airchime K series; several tunings are available and the chords and sound are very different compared to the M or P. The P horn (out of tune) is still in production, they will build the M if you can afford them (think thousands of $$$ each).
The Leslie Supertyphon and Prime knock-offs seem to be the ones disappearing. Their S3L used to be standard on many EMDs and used by ATSF and UP - now rarely heard. BN used the Canadian tuned S3K. Some of the S3L horns sounded great, and their 5 chimes are excellant. SP did not use Leslie horns, but I know for a fact that many of the M-K GP40M-2 rebuilds (&274-7299 and 7100+) got Leslie/Primes.