PrestonTom Posted December 14, 2006 Share Posted December 14, 2006 I am still toying with the idea of building a jubilee. I have both a question and a thought. What is the dispersion for a K402 (the bigger of the jubilee horns) and a K510. I assume these are CD horns (or at least to a certain degree). The second part of the question is how much EQing is going to be needed since it will be 2-way system. Part of the EQing will be required to offset the CD characteristics of the horn and I also assume there will be a rolloff since the horn will not be "loading" the higher frequencies (smaller wavelegths). I guess my question is really about the polar plots of these 2 horns (I assume with a K69 driver or something comparable). One of the things that is generally ignored by amateurs like my self, is that the dispersion between drivers at the nominal crossover region should be roughly comparable ). Part of the reason is that there could otherwise be a discontinuity between the relative contribution of the direct sound and the secondarily arriving sound as you went up in frequency ( I am assuming the lower frequencies from the big bass bin will not be "beamy" at all). So although the the amplitude spectrum may measure flat on-axis it will be different off axis and the result will sound "attenuated". This effect, of course, can also be exacerbated by the interaction of the speaker with the room. (I only recently remembered this issue because of some stuff Shawn was discussing in another thread As I think more about this possible project, I am starting to think more carefully about some of the details (headaches & compromises). Goodness only knows how many other details I am ignoring. I guess that is why engineers get paid.... Your collective thoughts and answers (if any of the polar plots are avalaible - or does tratrix have a "general form") are appreciated Thanks, -Tom Quote Link to comment Share on other sites More sharing options...
DrWho Posted December 14, 2006 Share Posted December 14, 2006 You should really read that very long thread where Roy so generously provided all of the data you seek...if you have no luck, I think I might compile it all into a single zip file. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted December 14, 2006 Author Share Posted December 14, 2006 Gee Mike, There are many long threads. I don't recall seeing the polar plots however. They may be averse to presenting some of this stuff on current production units since consumers frequently get confused if the description is a function rather than a single number. If that is the case, I understand. -Tom Quote Link to comment Share on other sites More sharing options...
DrWho Posted December 14, 2006 Share Posted December 14, 2006 Ya, sorry for being ambiguous...here's a zip file for ya Jubilee.zip Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted December 14, 2006 Author Share Posted December 14, 2006 Thanks Mike, I understand why these were zipped. For the life of me I don't remember these being previously posted. I will look at them later this week and at some point you will need to explain the Y-axis. Good Luck, -Tom Quote Link to comment Share on other sites More sharing options...
DrWho Posted December 14, 2006 Share Posted December 14, 2006 It's just a different way of looking at the dispersion at every frequency all at once...I believe the Y-Axis is the angle at which the polar response is 6dB down for the given frequency. A flat line would indicate a flat power response (perfect constant directivity). Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted December 14, 2006 Author Share Posted December 14, 2006 Ah ha, I was confused by the units (dB - probably a hicup from a previous plot). But the numbers were consistent with degrees, so I was wondering if these were angles for 1/2 power points (3 dB) or something. Thanks, -Tom Quote Link to comment Share on other sites More sharing options...
DrWho Posted December 14, 2006 Share Posted December 14, 2006 oh wow, I never noticed that before! Yeah, them's degrees on the y-axis... Quote Link to comment Share on other sites More sharing options...
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