Hi Greg-
In all honesty I'm not as well equipped for this discussion. I'm operating on info gleaned from the engineering guys when I worked at Altec. Their attitude was that operating the 511 down to 500 wasn't a good idea. That's where I got the 485 Hz figure.
I have used the Community RH-90. It's a 400 Hz flare rate horn. In A/B situations it sounds much better than the 511 at 500 IMHO. On the 511 it sounds like the driver is struggling compared to the RH-90. There are other possibilities for this- I don't care for the throat design of the 511. But I've operated on the above info.
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