Edgar Posted July 9, 2008 Share Posted July 9, 2008 Your point was just being discussed on another forum by McBean. I lurk at Audio Asylum, but I missed that one. It is not at all uncommon to find David McBean there. Greg Quote Link to comment Share on other sites More sharing options...
Marvel Posted July 9, 2008 Share Posted July 9, 2008 Bruce, I noticed that Eric doesn't have the tractrix midbass horns in his system anymore. He is using a 77Hz midbass exponential straight horn. jc I noticed that too. I think, among other things, he just likes to make sawdust. [*-)] Quote Link to comment Share on other sites More sharing options...
jwc Posted July 9, 2008 Share Posted July 9, 2008 OK fellas. I need clarification. Check my red circles. This is for a 120 liter cabinet, 2 K31's, 580 sq in throat, 1/8 space. 46 cm horn????? 107.6 dB at 40Hz??? jc Quote Link to comment Share on other sites More sharing options...
jwc Posted July 9, 2008 Share Posted July 9, 2008 Here it is on the spreadsheet program. Now the speadsheet won't give a predicted acoutic response. This is full space so I assume the "90 degree" from flare or whatever. Am I on the right track???? jc Quote Link to comment Share on other sites More sharing options...
Edgar Posted July 9, 2008 Share Posted July 9, 2008 46 cm horn????? 107.6 dB at 40Hz??? K31 is a pretty sensitive driver to start out with. Running two of them adds 3 dB. Running in halfPI space adds another 9 dB. So 107 dB SPL is not outrageous. The horn is so short that it's probably not doing much at 40 Hz. Greg Quote Link to comment Share on other sites More sharing options...
jwc Posted July 9, 2008 Share Posted July 9, 2008 I just can't see a horn 46 cm going that low. I'm gonna quit crunchin numbers for Tractrix Quote Link to comment Share on other sites More sharing options...
ajsons Posted July 10, 2008 Share Posted July 10, 2008 jc, check your emails. aj Quote Link to comment Share on other sites More sharing options...
Don Richard Posted August 4, 2008 Share Posted August 4, 2008 Sorry to be disputatious...the concept of sitting inside the horn is advertising puffery from the 40s, and is just not true. Real horns don't have doors, windows, etc as openings. If it was true, why did Paul state that a false corner need not extend beyond four feet? The Davis book repeats the Klipsch advertisng line, out of respect for Paul. I think we agree on the results, just not the description of how we get those results. My point was that other would-be corner horn designers should have the right understanding of what corner actually does for a horn. www.audioroundtable.com/PiSpeakers/messages/13611.html At low frequencies we are not dealing with a simple 90 deg. trihedral corner. The ceiling also becomes a loading boundary, further constraining the radiation pattern at frequencies whose wavelength exceeds the ceiling height. Therefore, at those frequencies, <140 Hz for 8 ft,, it appears we are actually sitting in the horn mouth. Quote Link to comment Share on other sites More sharing options...
DrWho Posted August 4, 2008 Author Share Posted August 4, 2008 I just can't see a horn 46 cm going that low. Why not? You can't obtain an "engineering feel" without playing with/measuring something first [] Try checking out the acoustical impedance to see what kind of loading the horn is giving you. It's actually better than the direct radiator... Quote Link to comment Share on other sites More sharing options...
jwc Posted August 4, 2008 Share Posted August 4, 2008 Mike. I'm not that good. I am just making a "visualization" statement. I haven't developed a confidence with the HornResp software yet. I dorked around with it for days and then stopped as I was going in circles with ideas. Maybe a 46cm horn can go that low. That would be a feat. So....since this thread was brought back to life........ Riddle me this....last time I promise (for now[]). Tractrix flare. Full 90 degree angle at Flare. 24 cm length horn. 90 sq in total throat. Mouth 45" wide and 33.5" tall. (2) K31's in a 35L chamber after volume displacement of drivers. Wired parallel. [8-|] jc Edit......yes I mean 24 in long. Quote Link to comment Share on other sites More sharing options...
DrWho Posted August 4, 2008 Author Share Posted August 4, 2008 You mean a 24 inch long horn right? (not cm)??? 35L might be a bit low for the rear chamber volume depending on how low you wanted your F3. Here's with 35L total rear chamber volume in black, and then 80L rear chamber volume in grey: Quote Link to comment Share on other sites More sharing options...
jwc Posted August 4, 2008 Share Posted August 4, 2008 Yes....24in long. You know my deal......sub plans later and XO 80-100Hz. Now you know my Midbass straight horn project. jc Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted August 5, 2008 Share Posted August 5, 2008 jc, check your Email Quote Link to comment Share on other sites More sharing options...
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