Guys... Very clear on "low frequency" as in the noise you can feel. I'm a fan of the hammer just because of the price and Feniex has gathered some serious reputation for arguably the brightest lights at the lowest cost so I imagine their hammer will live up to their reputation. I've heard it in person and it definitely works as advertised, never heard any other side by side it but seems comparable to others PD uses for more than double the price.
Have to agree with Wailer on this. The older Federal Interceptor series 2D or Director series 1D have the nostalgic slower lower pitched wail and yelp sounds. Also the old SP and Dietz brand sirens had great low tones.