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I was wondering if someone has attempted to mechanically narrow the beam of a Maxsonar ultrasonic rangefinder

I checked with Maxbotix and they told me this will require a paid NRE fee for the engineering time to narrow the beam, or consider buying one of the outdoor editions which costs 5-6 times more. But I was wondering if the cone is actually narrowing the beam or is it only in the design of the transceiver electronics.

I know that the EZ4 has the narrowest beams but also shorter detection range of human figures (at least that's what it says on the pattern graphs).
Yea, an acoustic cone would mechanically narrow beam and reception, but depending on material used there could be either distortion in the measuring calibration or reduction of range/sensitivity.
Similar to how microwave communications 'horn' antennas work, specifications are affected by whatever frequencies the antenna will be use with.
Like, a trumpet flare on a Tuba mouthpiece wont sound nearly as loud and full (wide bandwidth) as the Tuba flare on the correct mouthpiece.
So, its possible to craft a reflective horn to the correct dimensions for ultra sonic waves (sub-radiowaves) to narrow your beam and detection angles with minimum losses... I dont know exactly what that equation is now, but it indeed exists.
get the horn dimensions wrong, and you could effectively kill the efficiency and output of the waves you are sending out.
Got time and $$, just build a set of varying scales of design range, test them all, and settle on the one that worked best...Edison style//