The Allertor was available as a 12 port siren but no one has ever come across an example in the wild.
Screamers and Allertors could do the Yelp signal if they were ordered specially.
Mason City, Iowa had a 10-12 port Banshee installed in 1969 along with some Allertors. It is long gone.
Some of the original Hurricanes were 10-12 port to comply with states that required non-harmonic dual tone sirens back in the 1960s.
Wisconsin was one of the last states to uphold this requirement. It was dropped around 1970 which opened the floodgates for ACA to use harmonic dual tone sirens.
Notice Hurricanes that went up in states that didn't have this requirement were 8-10 or 8-12 port from the beginning. The majority of Hurricanes were gone by 2000 so we'll probably never find such a siren.
The Penetrator sirens never had damper valves. All you're looking at in the Eden Prairie video is a mesh screen stitch that might have a support behind it. Notice there is no solenoid box on the intake valve, much less an actual damper flap.
Some single rotor Banshees did have a solenoid damper. This photo turned up in a search, showing a dual tone Banshee with damper however its shroud is absent. You can see the motor top hidden under the cupola roof and its mounting platform beneath the intake.
The ones in Dane County were 9-12 port and installed in 1970. At least one in Maple Bluff also had a damper like this siren.

- Banshee 110.
- MarylandBanshee3Signal.png (260.65 KiB) Viewed 4580 times