greg928gts Posted January 6, 2009 Share Posted January 6, 2009 I've heard of the rule about XO at double the Fc of a horn before. I'll have to look at that link tonight. I thought it was the Fc should be 1/2 octave lower than the XO point. For a 400Hz XO, the Fc should be at least 300Hz. Greg Quote Link to comment Share on other sites More sharing options...
capo72 Posted January 6, 2009 Share Posted January 6, 2009 Here is what I plan on doing with my DIY tractrix horns.Maybe someday i'll finish them. They have been sitting in the back of my workshop like this for over a year now. All this recent talk about this horn has got the fire lit again. Jeremy Quote Link to comment Share on other sites More sharing options...
greg928gts Posted January 6, 2009 Share Posted January 6, 2009 GotHover - I'm curious, why is the tweeter under the midrange horn? I've seen this before. Is this preferable in any way? Do the waves from the midhorn interfere with the sound coming from the tweeter? Do the highs mix in better with the mids? Greg Quote Link to comment Share on other sites More sharing options...
capo72 Posted January 6, 2009 Share Posted January 6, 2009 Here is my driver compliment: JBL 2245H woofer JBL 2482 midrange compression driver Bob Crites Ct125 tweeter Quote Link to comment Share on other sites More sharing options...
Deang Posted January 6, 2009 Share Posted January 6, 2009 Here is the spec sheet for the BMS 4591: http://www.auraaudio.fi/Pdf/BMS/bms-4591.pdf The driver can go down to 300Hz. Here is a thread with some opinions about crossing it over that low: http://srforums.prosoundweb.com/index.php/t/13416/0/ Quote Link to comment Share on other sites More sharing options...
Deang Posted January 6, 2009 Share Posted January 6, 2009 Beautiful drivers. I would stay with the well established patterns of usage. Really nice job on the horns in this thread btw -- sorry if I haven't mentioned that. Quote Link to comment Share on other sites More sharing options...
jwc Posted January 6, 2009 Share Posted January 6, 2009 GotHover - I'm curious, why is the tweeter under the midrange horn? I've seen this before. Is this preferable in any way? Do the waves from the midhorn interfere with the sound coming from the tweeter? Do the highs mix in better with the mids? Greg That was my idea. I've seen a few guys such as Q-Man and Cut-Throat remove the tophat of their Khorns. Then put a massive midrange horn on top of a K77. The K77 is mounted in a thin baggle under the big horn. Looks good to me. The tweeter sitting bare on top of a big midhorn is a challenge for good looks (don't kill me Terry). Besides.......I like the tweeter lower.....like at a seated listening level. I noticed this when listening to la scalas and cornscalas. Anyway....I have no data greg. OO...Greg. Yes the rule is 1/2 octave above Fc...but I've heard before as an unwritten rule.......an octave. I'm not making an argument for either one. Gothover. YES...looking better. That is what I had in mind. The shorter that tweeter baffle..the more it looks like a "riser"for the big mid horn.....somewhat like a rider for the top hat of a khorn. jc Quote Link to comment Share on other sites More sharing options...
jwc Posted January 6, 2009 Share Posted January 6, 2009 Here is the spec sheet for the BMS 4591: http://www.auraaudio.fi/Pdf/BMS/bms-4591.pdf The driver can go down to 300Hz. Here is a thread with some opinions about crossing it over that low: http://srforums.prosoundweb.com/index.php/t/13416/0/ Dean....those guys are talking about doing that for High SPL pro situations. Crossing a compression driver down at 300Hz would call for a lot of blown diaphragms I bet. In these situations.....cones on a horn. Why not put a cone horn on a Khorn down to 300Hz. Anyone interested on this? 6-7" radius throat???????? The snare would have a lot of kick I'll read up on the other link earlier. jc Quote Link to comment Share on other sites More sharing options...
Deang Posted January 6, 2009 Share Posted January 6, 2009 No one wants to hear this, but the tweeter should be flush with baffle without any hard reflective surfaces around it. Quote Link to comment Share on other sites More sharing options...
jwc Posted January 6, 2009 Share Posted January 6, 2009 GotHover. Looks much better now that the tweeter mount height is shorter. Can you go any shorter? jc Quote Link to comment Share on other sites More sharing options...
capo72 Posted January 6, 2009 Share Posted January 6, 2009 GotHover - I'm curious, why is the tweeter under the midrange horn? I've seen this before. Is this preferable in any way? Do the waves from the midhorn interfere with the sound coming from the tweeter? Do the highs mix in better with the mids? Greg The tweeter sitting bare on top of a big midhorn is a challenge for good looks (don't kill me Terry). Besides.......I like the tweeter lower.....like at a seated listening level. I noticed this when listening to la scalas and cornscalas. jc My tweeter will be under the mid horn for the reason stated by jc. They will be much closer to ear level this way. My big boys come in at 56" tall, that's 10" taller than an RF-7. My tweeter will be at about 39" from the floor which is the same as the RF-7 tweeter. I will be able to angle the mid horn down if necessary. Jeremy Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 6, 2009 Share Posted January 6, 2009 Ever seen this? http://ldsg.snippets.org/HORNS/storede.html Is there any form of xover in the signal path? And what is the output impedance of the amplifier he's using? I suppose to be complete, what's the impedance of the wire he's using too? Impedance response of the driver on a plane wave and the impedance of the driver on the horn? How bout a measurement comparing two different horns with very different cutoffs? Also, why not just post a waterfall? Measuring at distinct frequencies isn't a very fair comparison when the resonances of various drivers are very rarely going to happen at the same point. Heck, two of the same model drivers are going to be off by a little bit. Anyways, what were you trying to extrapolate from the link? I think I got a bit sidetracked... Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 6, 2009 Share Posted January 6, 2009 Why not put a cone horn on a Khorn down to 300Hz. Anyone interested on this? 6-7" radius throat???????? The snare would have a lot of kick I've been looking for a long time for a cone driver that can cover 100Hz to 1kHz...haven't found anything that models up like I'm looking for. However, if you want to throw polars out the window, then it's pretty easy to accomplish with collapsing polars. Quote Link to comment Share on other sites More sharing options...
Deang Posted January 6, 2009 Share Posted January 6, 2009 Dean....those guys are talking about doing that for High SPL pro situations... I thought that's what you guys were doing. [] Quote Link to comment Share on other sites More sharing options...
Deang Posted January 6, 2009 Share Posted January 6, 2009 Hey Mike, your post kind of lost me. Sheerin's page starts with a link to Linkwitz's site where he talks about measuring driver distortion -- you might want to start there and then go back to Sheerin's page to understand what he's doing. At any rate, I just thought it was interesting, and his results give another reason not to cross over near the fc of a horn. Quote Link to comment Share on other sites More sharing options...
Deang Posted January 6, 2009 Share Posted January 6, 2009 However, if you want to throw polars out the window, then it's pretty easy to accomplish with collapsing polars. it's an imperfect world -- but we get to pick our own poison. I've been looking for a long time for a cone driver that can cover 100Hz to 1kHz...haven't found anything that models up like I'm looking for. I think I know of a driver that might work, but I need to remember where I saw it! Quote Link to comment Share on other sites More sharing options...
Guest David H Posted January 6, 2009 Share Posted January 6, 2009 No one wants to hear this, but the tweeter should be flush with baffle without any hard reflective surfaces around it. I agree and that is easy enough to change, but looks better behind. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted January 6, 2009 Share Posted January 6, 2009 Here is what I plan on doing with my DIY tractrix horns.Maybe someday i'll finish them. They have been sitting in the back of my workshop like this for over a year now. All this recent talk about this horn has got the fire lit again. Jeremy Jeremy you need to get back to work on that...Your project looks great so far. Is that an 18" woofer cutout? Nice.... Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 6, 2009 Share Posted January 6, 2009 and his results give another reason not to cross over near the fc of a horn. I disagree (even after reading Linkwitz's site) in the sense of there being an undeniable direct correlation between the measurement and the Fc of the horn. I would argue that there is a lot more going on. However, that's not to say that I think you should cross below the Fc... I think I'm arguing causality versus correlation. Btw, people run bass horns below the Fc all the time, yet never bat an eye. Just look at the Altec VOT, or Lascala... Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 6, 2009 Share Posted January 6, 2009 I think I know of a driver that might work, but I need to remember where I saw it! That's not sarcasm is it? (just wondering if you are trying to infer using the K-31...I don't think it hits the mark, but comes close...tipped too much towards the low end). Quote Link to comment Share on other sites More sharing options...
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