Interesting and Inexpensive Wave Guide

[Spanky Ham]

Thylantyr pointed out the Elsinore speaker over on AVS. It uses a wave guide that he calls a diffraction wedge. I thought it was a unique way of making a wave guide. Any thoughts?

[JonMarsh]

This is a somewhat primitive approach to a waveguide, I would like to see what the off axis plots look like- that he lines this with felt to kill reflections gives some hints about issues with the behavior.

But a lot of thought and effort obviously went into this, it's just frustrating to read considering the information he's left out so far...

I think the appellation "diffraction wedge" may be much more appropriate than waveguide. What I would want to see is a series of on axis and off axis plots (horizontally and vertically, since it's not symmetric) similar to those posted by others for various driver/waveguide combinations, or like the plots I took last weekend for the BMS4540 and DDS ENG-1.



This is the raw response, before shaping by the crossover; in this case, the target would be additional attenuation below 10 kHz of the driver level, some shaping at 2 kHz, then a steep crossover around 1.8 kHz.

These curves were taken between 0 and 45 deegrees off axis; at the outside range of the waveguide, not that the basic FR profile remains largely the same, just the level drops going off axis.

[JoshK]

if one wanted to get creative, instead of a pyramid like waveguide with four sides, you could add additional sides, 8, 16, 32, .... estimating a cone with successively smaller and smaller sides...kinda like calculus. Might be more work than its worth though.

[timber_mg]

Well it's kinda like adding foam to the sides of a B&W tweeter to make it palatable in anything other than the deadest of rooms. He will suffer a bit of diffraction at the transition but otherwise it may well be an improvement above just a normal tweeter.