PJD642 said:
... CPI in my personal experience makes very high quality speakers that project very well. You may also want to consider a Federal 200 watt speaker - may be cheaper than purchasing two 100 speakers....
We were doing some research for a large ambulance customer (450 ambulances). They wanted to ensure all their siren systems met SAE specifications. At that point, they were running a bunch of everyone's speakers, including CPI. When I called CPI's engineers, they told me that they don't test the speakers. At all. They said they tested the driver itself , but didn't test the driver once it was in their housings. Personally I think that's silly as the speaker housing can dramatically affect the output. That turned me off CPI in general. I had to pass that along to the ambulance service, and so they dropped CPI because they couldn't guarantee that their speakers met SAE. That was probably 5-6 years ago so it may have changed.
There are only a few places that manufacture drivers. FedSig makes their own in the US, Whelen buys theirs from Taiwan, and I believe Atlas still is making drivers. A number of manufacturers buy from Atlas and a couple buy from Federal Signal, then put their own housing and label on it.
That same ambulance service mentioned above has 2 x SA315's on the front bumper of most of their ambulances. They had a >30% failure rate (I don't know the actual rate, but it was in excess of 30%) with them. I can't imagine that all SA315's have that same failure rate otherwise no one would buy them, but that's what their fleet guy told me.
The MS100's used to have major reliability problems back in the early 2000's, but those have long since been solved, and the ES100's have proven to be very good. The ES100's are a compact speaker so they still meet SAE but they are a couple dB quieter than the AS124's. The AS124's are just fantastic - we almost never hear of a failure, and they are extremely loud (might only be talking a couple dB's , though, so it's all relative). The AS124's are bulkier than the SA315, but they're also less expensive and don't require a bracket to mount on a flat surface like a push bumper. We go through literally tons of them a year and customers love them.
Keep in mind that all siren speakers' volume degrades after a few years in the field. You can lose 3-5dB after 3-5 years , depending on the conditions it is exposed to. We always recommend that customers buy new speakers for new vehicles (don't re-use them from old cars ) just for that reason.
Hope that helps.