![]() Here, regarding the relatively large overhangs I'm working with, the ~1 dB and less differences are audible. Wayne Parham did some studies in the course of designing his Pi speaker product line and found that while roundovers made measurable differences, they were not audible. True, the SPL is not entirely attenuated outside the -6 dB specification window, so there is still opportunity for trouble-making. My frame of reference is constant-directivity waveguides with respect to which one might rationally presume that having defined dispersion patterns, there would be less of an issue than with wider dispersion sources. I am going to make a horrible generalization and say that I tend to like the sound of larger horns. Even though it still "pending" as an official waveguide it seems like a few have had success with it. ![]() Thanks for your responses, I have decided (after much waffling) to go with the QSC waveguide. This would maximize diffraction related response irregularities. I would bet that a waveguide will actually illuminate the edge more strongly than a flush-mounted driver because the wavefront is "guided" through the waveguide into a gently opening "space", including along the edge of the waveguide and outward radially towards the baffle edge. It's best to measure the actual driver in the actual enclosure and go from there. It depends on the driver so this is not a rule of thumb. This may provide the following advantage: If the driver's off-axis response has decreased appreciably by the frequency of the "bump", the "bump" amplitude may be reduced significantly if there is little to no sound pressure radiated in the plane of the baffle by the driver. Then measure after you have the drivers in the cabinet to double check the response before making up your final crossover.įinally, keeping the width of the baffle as narrow as possible will help to keep the first "bump" of the ripples as high in frequency as possible. This is useful even before you build the cabinet to plan for response irregularities. It's best to model these effects using programs such as Jeff Bagby's "Baffle Diffraction and Boundary Simulator" (for single drivers) or "The Edge" (for multiple drivers of the same diameter) or the "Baffle Diffraction Simulator" (multiple drivers of different diameter). Larger drivers will have slightly less ripple than a smaller diameter driver at the same position. Locating the driver so that it has different distances away from nearby edges is helpful. a 6 inch driver mounted 8" down from the top in a 10" wide baffle. The ripples are worst when the driver has equal distance from top and sides, e.g. around 400 Hz, in these figures, however IMHO that is that would only result from a baffle that is quite wide, e.g. The main thrust of the page is the baffle step transition, but there are four figures in the middle that illustrate the response from "real" loudspeaker enclosures of various shapes and the "ripples" that I am referring to.įor the typical rectangular box, there is a usually a peak of 2-3dB in addition to the baffle step, somewhere in the vicinity of 800-2k Hz (shown at a much lower frequency, e.g. True Audio Tech Topics: Loudspeaker Diffraction Loss and Compensation
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