Regarding OS wave guides, I've seen some predicted directvity plots posted with jagged edges (see attached). Of course others can be found that are smooth... predicted or measured. What's causing this ripple effect? What aspect of the waveguide design can be changed to minimize this from happening? Or could it be a matter of resolution or smoothing of the data?
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Off hand, that looks like a spatial interference pattern (recognized by it's pattern of lobes and nulls).
It would help to see the color scale showing how many dB = each change in color. Traditional polar plots over that same frequency range might be more informative. How large is the horn and the driver?
Yes, smoothing as with frequency response will help it's appearance but not the sound.
That is an obvious case of waveguide edge diffraction. You cannot simply terminate a waveguide with a sharp edge because you will get this kind of pattern. The edge must have a radius to prevent this.
It also will not be seen quite this extreme if the mouth is not round. Round mouths cause the diffraction from every point on the edge to be the same phase. An elliptic or square mouth will smear the results. Round with a liberal radius is still the way to go as a very good response can be obtained. With round, varying the radius of the edge treatment will also have a similar smear effect.
It also will not be seen quite this extreme if the mouth is not round. Round mouths cause the diffraction from every point on the edge to be the same phase. An elliptic or square mouth will smear the results. Round with a liberal radius is still the way to go as a very good response can be obtained. With round, varying the radius of the edge treatment will also have a similar smear effect.
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