If you were using a real Federal doubletone siren you'd be in good shape. But I've never cared that much for the dual-amp. electronic sirens. But I did run across one the other day on YouTube that sounded almost like a Federal doubletone siren: close but no cigar!
For you youngsters around here, the doubletone sirens have a dual rotor cast together. One of the rotors has 8 ports and the other 16. That gives simultaneous high and low pitches. The only downside of the doubletones was their size: 7 1/2" rotors. They did have a decent range to them, but nothing compared to a Q or B&M Super Chief.
When my REACT team in Lubbock back in the late '60s became involved with providing first aid for the local racetrack we had use of the track's ambulance, an old '60 Chevy station wagon. At he time all it had was a single Federal 17 beacon on top.....period. But on May 11, 1970 Lubbock was hit by a massive F5 tornado. We were able to mobilize with an ambulance borrowed quickly from a local ambulance dealer. Long story short we had a lot of good publicity from what we did that night and a few days following the storm; and as a result we were given the old track ambulance. And surprise, surprise, we discovered that the owner had a nice 77GB doubletone siren put away that had simply never been put on the car, although there were holes in the fender where it would've gone. And that's where it went! We discovered that at some point in its history the siren had been rebuilt and had an oversized motor That siren would scream. One of our members worked at a movie theater that happened to be on the route we would take when we transported to the then-Methodist Hospital. One Friday evening he had to work at the theater, and sure enough we had a run. He had just come downstairs to the lobby for a quick break at the exact moment we were approaching the intersection closest to him. He would later tell us that when we hit the intersection (and I was driving) that that doubletone siren rattled the plate glass windows in the theater. I've heard stories about the high-pitched friction sirens on police bikes doing that, but never from a siren like that doubletone. I would come closer to believing that from a Q or Super Chief!
When I was in my early teens I had done a science class project on sirens and had become acquainted with one of Federal's managers who had supplied me with all sorts of neat literature on everything that they built at the time. So I asked him totally out of curiosity why they hadn't built a dual-toned Q....considering the neat sound of the doubletones. He said that they had built a prototype and a few models to see how they would go over, which they didn't: end of that story.
So back to the obvious topic here, if someone would produce a twin-amp electronic siren that would give a real dualtone sound, I'd be the fist to grab one!
