I think that what you are hearing is the resultant tone of the perfect 4th interval that these sirens produce. Any siren that has a 9/12 port ratio, such as the Model 5T, P-10, most Allertors, some 500ATs, and the Banshee, will generate perfect 4th interval. This interval (the space between two musical frequencies; in this case, C and F on a piano) has a particularly harsh and prominent resultant that is two octaves below the higher note (F). The first time I heard a 3T22, which sounds a minor 3rd interval, it sounded like a three-tone siren playing a Bb major chord, with the resultant Bb in addition to the D and F notes.PhRed wrote:One question, tho:
As it is with this kind of dualtone siren, so with all others (SD-10, Federal 5T, dual Allertor & Banshee, etc) like the Penetrator here presented.
I particularly hear the deep buzzing sound that matches the high note and is common to all models above-mentioned...is this the siren's motor? Somehow, I don't think it would come from a third rotor and vane component.
The shape of the intake usually has nothing to do with dual or single tone. The later P-15s made before ACA changed over to ASC thus changing them to RM-127s, had the straight intake cone, and if I'm not mistaken were only single toned. I saw a dual toned P-15 in TMI's system a few years ago. It had the cone shaped intake like the other P-10s in their system.RamFett wrote:Really? So the intake cone's shape doesn't mean P-10 or P-15, but rather single or dual tone?Archon wrote:I played this video for a guy who repairs sirens he says It's a P-15
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