What's the impedance of a SA315P ?

[Sigma Safety]

I'm trying to find the impedance on an SA315P speaker for some calculations we are doing for a customer.  I do not have one of the speakers here otherwise I'd measure it, and I don't see the number in the Whelen specs anywhere.

Is it an 11ohm speaker, or something odd like 5.5ohms?  Does anyone know?

Thanks

 

[MtnMan]

Any 100 W siren speaker should be 11 Ohms impedance.

I was puzzled by this response:  but I can only guess that Whelen was referring to the DC resistance, as you would measure with a multimeter, rather than the actual impedance.

 

[Sigma Safety]

Thanks MtnMan.

So, what confuses me is the specs on the Cencom Sapphire.  Assuming the use of an 11 Ohm speaker, the Sapphire only puts out about 43 watts into a 100 watt speaker.  If you use 2 x 100 watt speakers, it puts out a TOTAL of about 85 watts.  This is assuming I did the math correctly.

The othe thing is that Whelen specs it using 15 volts input, which is not realistic (unless it's really cold weather).  It should be 13.6 which is the standard test voltage, which is a 9% difference so really their specs are 9% high (13.6/15 = 0.91)

Here are the specs from the Whelen website;

• [SIZE=11pt]24 VRMS into 11 ohms @ 15 volts DC[/SIZE] [input]  = 52 watts output (at 15vdc input)
• Adjusted for 13.6 volts input to the siren amp, this gives only 43.4 watts of output power

By comparison, here is the FedSig spec for their sirens;

• 33 VRMS into 11 ohms @ 13.6 volts = 99 watts

What am I missing here??  Do the Sapphires really only put out 43.4 watts of siren power into a 100 watt speaker??

 

[MtnMan]

I think the 24 VRMS spec refers to the PA function.

 

[Sigma Safety]

I'm trying to see how that might be the case. It looks like they rate the siren amp module at 24vrms and they mention the audio bandwidth (PA) at 25 watts.  Hmm....