moray james Posted February 2, 2012 Share Posted February 2, 2012 I have been looking at the new tweeter lens used in the H3 (k107T1) and also at the T35 lens. These two tweeter horn lens are very similar. They look so similat I have a hard time understanding why the T35 is considered a diffraction horn and the H3 horn is not. Does anyone have polar response graphs of these two tweeters. Can one of the Klipsch Engineers comment on this? It is easy to see the physical differences but they are still much more alike than different. I am wondering if the ner T3 horn really ought to be vertically mounted like a T35? Comments would be most welcome. Thanks for any and all input. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
Groomlakearea51 Posted February 2, 2012 Share Posted February 2, 2012 Did you check with Bob? He may have already done something. Quote Link to comment Share on other sites More sharing options...
moray james Posted February 2, 2012 Author Share Posted February 2, 2012 good point which I should have considered. I have been chewing up Bob's time with another question and I don't want to pester him to death. So if Bob see's this great. I woluld love to hear from the technical department if possible on this on. The ought to have plots on these things. I have not looked yet but plots for the T35 and the APT 50 ought to be around. I imagine Bob has them for his CT125 all of which are essentially the same animal as a K77 or T35. Hope one of the Klipsch engineers picks up on this. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
Greg Oshiro Posted February 3, 2012 Share Posted February 3, 2012 I was going to post a similar question, but you beat me to it. I've been noticing that my Klipschorn tweeters (K-77/T35) sound like they have very narrow horizontal dispersion. My K-horns have the tweeter mounted on the back of the motorboard. If anyone in the DFW area has a top hat that is in poor cosmetic condition which I can borrow (and likely return in *worse* cosmetic condition), I'm willing to make some polar measurements and post them here. I'm not willing to take furniture-grade finished top hats into the parking lot for measurements. Transducers need not be included with the top hat. Grille cloth must be installed. I am willing to transplant my horns/drivers for these measurements. Another option might be a dimensionally accurate top hat copy with grille cloth installed. Do any of the woodworking forum members have a top hat that didn't turn out quite right? Quote Link to comment Share on other sites More sharing options...
moray james Posted February 3, 2012 Author Share Posted February 3, 2012 Greg: if I was in the area and had parts for you I would be happy to help. If I recall correctly (and I can't always count on that) the numbers for a T35 with the long axis in the vertical position is 80 degrees H and 30 degrees V. Looking at the T35 and the H3 tweeter it is easy to see the physical similarities. I don't undearstand what makes a diffraction horn work the way it does and why a tweeter like that in the H3 does not behave in the same way. If someone in the local area has a T3 tweeter could you measure it? Do you have a turntable set up to do polars? Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
LarryC Posted February 3, 2012 Share Posted February 3, 2012 My K-horns have the tweeter mounted on the back of the motorboard. Klipsch eventually changed this to flush-mounting them on the front of the top hat motorboard, by cutting a larger opening and using "Z-brackets". This allows retrofitting.It looks like Bob Crites can furnish you with details and maybe the Z-brackets: http://www.critesspeakers.com/klipsch_tweeters.html Quote Link to comment Share on other sites More sharing options...
Don Richard Posted February 3, 2012 Share Posted February 3, 2012 Hi, Greg. Here is some info on rear vs front mounting the Khorn tweeter. No polars on vertical mounting but interesting nonetheless. http://community.klipsch.com/forums/p/155314/1637501.aspx#1637501 Quote Link to comment Share on other sites More sharing options...
Greg Oshiro Posted February 3, 2012 Share Posted February 3, 2012 <snip> If someone in the local area has a T3 tweeter could you measure it? Do you have a turntable set up to do polars? <snip> Yes and yes. There are some practical considerations, though. The tweeter's polar behavior will depend on the size and shape of the baffle in which it's mounted. So an adapter has to be made that somewhat mimics the speaker system in question *and* readily adapts to my turntable. If anyone is interested in providing something for measurement, let's have a discussion of all the details... Also, I don't view directional data as polar plots. I view directional data as seen in the attachment. The horizontal axis is log frequency, the front to back axis is angle (the example data set has on-axis in the center) and the vertical axis is response magnitude in arbitrary dB. My measurement environment limits low-frequency capability, so the data below 200 Hz should be viewed with a raised eyebrow. ************************************************************************************************************************************************************************* *Beware that real speaker measurement data is ugly, almost all curves seen in reviews, datasheets, etc have been smoothed by the marketing pen* ************************************************************************************************************************************************************************* A perfectly flat omnidirectional speaker would have flat lines across all the measured angles. The data can also be normalized to the on-axis response so only the directional differences from the on-axis response are displayed. Quote Link to comment Share on other sites More sharing options...
Greg Oshiro Posted February 3, 2012 Share Posted February 3, 2012 Hi, Greg. Here is some info on rear vs front mounting the Khorn tweeter. No polars on vertical mounting but interesting nonetheless. http://community.klipsch.com/forums/p/155314/1637501.aspx#1637501 Don-- Those plots correlate with what I hear. The rear-mounted off-axis curves are much worse than the front-mounted. I don't have the woodworking capability to enlarge the tweeter holes to accommodate the Z-brackets without damaging something. Maybe I'll get new motorboards from Volti someday if Greg's still doing K-horn mods. The first item on the list is measuring what I'm currently listening to so I have baseline data. --Greg Quote Link to comment Share on other sites More sharing options...
WMcD Posted February 3, 2012 Share Posted February 3, 2012 Take a look at this thread where SpeakerFritz posted the spec sheet for the T35-A. The polar pattern narrowing of the vertical and horizontal don't match exactly, yet they are fairly close. I'm not totally sure that diffraction is how these work in principle. There is reason to think that it is just the relation of the exit angle and the dimension of the mouth (although in the very early days we see the ratio of width to height of 10 or so). Generally the effect of narrowing and control of angle is described by Don Keele in his several papers. It is correct that the Cornwall II of 1969 allowed vertical or horizontal orientation of the mid and tweeter by just turning the box. People had favorites. Note also that the mid and tweeter were some distance apart. Maybe the thought was that the radiation pattern of each benefited by a clean plane of plywood for acoustic loading and predictable patterns. We really don't know about the interference pattern created at the crossover freq where both the mid and the tweeter were sounding. Also, the interference pattern between the woofer and the mid. It seems to me that we see a first step in what became the revised Cornwall when the woofer, mid, and tweeter were moved into vertical alighnment. The mid and tweeter were placed close to each other. This may have been a means to control the interference between the mid and tweeter. The bass driver was close to the floor. But in the CW III the woofer was moved up close to the horns. Again this may have been to optimize the overlap patterns. Of course if you have horns with retangular mouths, and you want to get them close, the horizontal (landscape) orientation is best. So the bottom line is that which orientation is best may well depend on interaction with the other drivers. WMcD . WMcD Quote Link to comment Share on other sites More sharing options...
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