what is a wave guide?

[Joules]

What is a wave guide ?

[Grahamt]

Someone will be able to explain it better than me, but in the mean time, it is a contoured low diffraction tweeter face plate.

[GM]

Greets!

Per Daniel A. Russell, Science and Mathematics Department, GMI Engineering & Management Institute:

"A waveguide is a structure which forces wave propagation along a path parallel to its longest dimension. Acoustic wavequides are structures with constant cross-sectional area and shape. Simple examples of such structures include hoses, tubes, and pipes.......".

Note that there are many folks, including some horn designers, that erroneously refer to low gain horns as waveguides.

GM

[dwk123]

Hmm, I'd say his definition is overly restrictive - I don't see any inherent reason why propogation needs to be strictly axial.

The Geddes definition might be closer to 'a device which transforms a particular velocity profile at it's throat to a specified velocity profile at it's mouth' ie 'guides' this input waves along a prescribed path to the output. (this is my own definition, I wouldn't presume to speak for Earl)

In common parlance as talked about around here, it's a horn with geometry that is designed to have a particular output radiation pattern. Most conventional horns are more concerned with acoustic gain than pattern control - a waveguide is concerned with pattern control rather than acoustic gain. Generally a waveguide will reduce to a conical flare at the mouth, but the throat geometry will be different and will be based on the geometry of the driver that is being used. The acoustic gain will be very similar to a conical.

[GM]

Greets!

While everyone is entitled to an opinion, a definition was asked for. Dr. Russell's is no different than the one in my '50s era collegiate dictionary so it seems reasonable to me that there's a good technical reason for it being so 'restrictive', I just don't know what it is.

GM

[Ed LaFontaine]

Dr. Geddes has said "All waveguides are horns, not all horns are waveguides". He strives for a more uniform output over a wider arc than is common with conventional drivers. He uses equalization for shaping the frequency response and acoustic foam to damp difraction within the waveguide...I think.

[jackinnj]

if you design a "waveguide" properly it can, itself, be a radiator -- of course this may be at microwave frequencies.

ordinarily we don't want our speaker cabinets to "radiate".

[Christof]

Here is some waveguide info from Bob Smith @ SP Tech. The following is a commercial site but provides some very good reading into waveguide/horn theory. I've heard Bob's speakers which utilize waveguided baffles and must say that he is one heck of a speaker designer.
c.

http://www.4sptech.com/waveguides.php