What phase of a P-10 or P-15 louder and carry the farthest?

[OfficialSquished]

What P-10 or P-15 phases on the siren is louder and how far can they to be heard from miles? I been wondering for the past like 7 1/2 years and I couldn't think of which phase on the siren of a P-10 or P-15 is louder on each one. Can you guys help me out?

P-10 (Dual Tone)
P-15 (Dual Tone)
P-15 (Single Tone)
P-10 (Single Tone)

Which one is the loudest and what are there different between decibels and coverage?
Can you guys compare and break it down for me?

Thanks!

[Darley Champion]

I would say single tone P15, since the dual tone rotor needs to "chop" more air and both "sub-rotors" share the same intake, plus the slightly beefier motor.

Although on a ST (Single Tone) P10 versus a DT (Dual Tone) P15 standpoint, I'd say the extra 5 HP of the P15 could eke out some extra decibels and compensate for the halved air supply on both rotors.

Now, in my examples I'm assuming the sirens are 3-phase for the sake of simplicity, with a single phase motor the decibel output would probably be a tiny bit lower.

(I don't really know what the P15/P10 specs are on hand)

[Snowpix]

The P-10 doesn't like the 8-port rotor as it's heavier, which puts more strain on the motor which may make it harder to reach full speed if it's worn. According to official documentation, the 8-port P-10 and P-15 are 127 dB, while the 9/12 dual tones are 125 dB. (Interestingly, the Allertor 125 is 126 dB according to documentation, likely because the intake and projector are separate.) The reason is that dual tone sirens can't carry as far, because the two tones clash which harms its ability to carry. There's a reason modern sirens are almost always single tone. As for single or three phase, both are capable of reaching the same sound output, but that entirely depends on how healthy the single phase unit's starter capacitors are. If the caps are bad, it won't reach full pitch and will be very sluggish.

The P-10 and P-15 perform identically, the horsepower doesn't make a difference in sound output. It just affects how fast it can wind up, and how the motor handles the load of the rotor.