In many cases a chamfer will have a better result than a rounding especially if the chamfer is relatively large. Although two having 2 peaks at each end of the chamfer. ![]() The diffraction peak frequency or apparent edge will be the halfway through the rounding.Ĭhamfering will have a similar effect. This is similar to off-setting the driver from the exact center. It smears it over a large frequency range as the edge is now seen as gradually fading. Rounding edges does not lessen diffraction. So, please don't be mad at me for questioning some of your answers, it's nothing personal and I'm just trying to understand. If I wanted easy I would just keep my mouth shut and solve my problems like everybody else but this is my hobby and I like to actually understand what I'm doing. From what I can remember the larger the driver the lesser the problem but I tend to mix things up. Since the driver isn't an ideal point source I'm sure real world impact will not conform to the most basic idealistic models. The angle of incidence argument would be interesting to hear more about since most people seem to work in the time domain when discussing diffraction and not so much in wave propagation and frequencies? How will a sharp edge on the cabinet compare to a framed painting on the wall next to the speaker? Or a bowl of fruit on the table in front of the listening position? Room acoustics will have a huge impact on the sound. I believe it's been proven that frequency irregularities below 1dB is at best incredibly difficult to percieve and most would say it's inaudiable. (I'm a mathmatician btw, numbers and research references are gold.) I'm not saying you're wrong but I would like to understand how it works and how big an impact it has. Rules of thumb and "everyone is doing it so it must be good" doesn't quite cut it. I don't want to be a poor sport but that's precisely the sort of answer that I'm questioning with this thread. What frequencies, multiples of fundamentals, or phase shifting.I don't know the particulars.It is of course easy to put a big a** radius on the edges to null out these nsider it a basic rule of thumb.a must do on any design. Same thing with AF.A 'retransmitting' of the signal originating at the baffle edge. Let's say the station puts out One megawatt of gets to that edge & 'stalls'.It 'stalls' at the edge of a mountain with only 3 watts of power.picture a phantom antenna, having only 3 watts of power now transmitting down the back slope of the mountain. but the edge where it "stalls" regenerates & starts 'transmitting' again at that edge. I would say "stall out" at the top of a hill/mountain. Did you ever wonder just why & how radio reception gets lousy when your deep within a valley.the station fades out? Wavefronts. My understanding is that AF wavefronts behave the same as RF wavefronts. ![]() How big does the rounding have to be to make a difference? I'd very much like to hear it from someone who actually understands this stuff.ĭoes edge rounding really do much difference if crossing around 1kHz using a HF driver + CD waveguide and a large DR woofer? When dealing with lower frequencies the wavelengths are so great that the rounding won't do much good anyway. Since the waveguid has such a focused directivity diffraction problems in the higher frequencies should be a non-issue. The woofer will probably match the directivity fairly well if done right. In a document found at Pi speakers you can read about the baffelwidth being a major issue and edge rounding not so much when it comes to lower frequencies.Ī waveguide might for an example exhibit a 90degree radiating pattern at the crossover frequency. Linkwitz who is a pioneer and authority in himself as well stipulates that rounding the edges will only provide benefits when the radius is greater than 1/8 of the wavelength. ![]() He recommends as large a edge radius as practical. Geddes is a pioneer and authority in the field. I'm planing on a two-way build with focus on constant directivity. However it would be nice to have a few questions aired. I'd be lying if I claimed to actually know the truth about any of it. I've been trying to read up on diffraction problems and cabinet construction.
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