How to measure beam pattern/dispersion?

[MorganMcLeod]

I'm building some 22 inch parabolic reflectors (out of papier-mâché, no less) and I want to measure their far-field beam pattern.
Also testing a few options for driver and amplifier. Baseline plan is they will run from 2 AA batteries so only one pair of signal wires comes from the source.

These are for a sound installation project and are not going to be super hi-fi, but I do want them to be as directional as possible. And I want to set the highpass cutoff appropriately to maximize directivity.

I'm figuring I can just do sweeps with REW at various angles in front of the reflector, then organize results in a spreadsheet or the like.

Any other suggestions for speeding up the measurement or the data processing?

If there's interest, I'll share more details about the project as it develops.

Thanks
-M

 

[MorganMcLeod]

Didn't mention: Small speakers at the parabola focus. So these are meant to create narrow sound beams.

 

[John Mulcahy]

You could play pink PN through the speaker and use the RTA to view the response changing live as you alter the angle, capturing individual measurements as you go using the buttons on the RTA. No averaging needed when using Pink PN, use Rectangular window.

 

[MorganMcLeod]

Thanks for the helpful suggestion. Up until now I've been imagining walking around with the microphone stand while the speaker is stationary. But it will be much simpler just to rotate the speaker. Reflections will behave differently but as long as reflecting surfaces are somewhat farther than the distance between the two, should be able to gate them out.