lorcoll Posted February 12, 2006 Share Posted February 12, 2006 I know many Klipsch owners have tried different mid horns like 511B, Cobraflex and now the ALK Trachorn, but I would know if the SM-120 are similar in the sound to the ALK Trachorn or what can I expect from them. I tried the 511B in my Khorn and come back to the K400. Wolfram have told me that the EV SM-120 are the best mid-horns he have heard on Khorn (he have replaced the Cobraflex with these). Thanks. Lorenzo. Quote Link to comment Share on other sites More sharing options...
lorcoll Posted February 12, 2006 Author Share Posted February 12, 2006 Another pic. Quote Link to comment Share on other sites More sharing options...
ajsons Posted February 12, 2006 Share Posted February 12, 2006 Lorenzo, Was the 511B damped or undamped when you tried it? I tried an undamped 511B on my SK, and didn't like it that much because "it rings like the Liberty bell", as one publication described it. There are many ways to cure that if you haven't done so. And when you do, you'll probably like it. I tried the cobreflexes too, they are also very good horns. There was a thread two or three years ago, called "Installing Mike's 511B" that has a lot of comparison info on these midhorns (and mid drivers). I presently use the SM120's, one on my SK, and one on a University Classic, and they're my preference. Here's a spec sheet. It says 500hz is its usable low freq, but EV has used it at 400hz with a 12db/octave cross in their Sentry IVB (it has a bass horn), and 3500hz for the EV T35. Also, check the first pictures on this thread. http://forums.klipsch.com/forums/657097/ShowPost.aspx I have not heard ALK's trachorns. Once I get enough money saved, I'll get a pair. Quote Link to comment Share on other sites More sharing options...
ajsons Posted February 12, 2006 Share Posted February 12, 2006 Page 2 Quote Link to comment Share on other sites More sharing options...
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lorcoll Posted February 12, 2006 Author Share Posted February 12, 2006 Yes, my 511B were undampened. Thanks for the data sheet. I have bought the SM-120 on ebay and I hope I can receive them soon. Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 12, 2006 Share Posted February 12, 2006 If that is a CD horn you may need the ability to EQ it to handle the rolloff of the horn. Shawn Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted February 13, 2006 Share Posted February 13, 2006 It's definitely NOT a CD horn, but it's a beaut. We used to use em in an EV pa stack and they sounded wonderful. Gave up some JBL's for them. They look el cheapo, but sounded very smooth. I can't give any recommendations for use in home systems however. Michael Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 13, 2006 Share Posted February 13, 2006 Doesn't look like a CD horn but the spec. sheet above certainly says it is. Shawn Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 13, 2006 Share Posted February 13, 2006 Guys, For what it's worth, I started with the 511b, the moved to the 811b, and finally to the Trachorns. I found that they sounded similar. Part of this is that the Altec horns were damped with generic "Dynamat". One of my original "golden ear" beta testers siad that makes a difference. Without the damping the Altech horns are not as good. The Trachorn has two-layer curved sides with an absorbant adheasive between the two. The damping is total. Al K. Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted February 13, 2006 Share Posted February 13, 2006 Doesn't look like a CD horn but the spec. sheet above certainly says it is. Shawn I stand corrected. Usually those CD's need some eq-ing. Maybe the CD quality is why I loved them for PA so much, they were'nt as beamy as many of our previous horns. Michael Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 13, 2006 Share Posted February 13, 2006 You can get away without the CD EQ on a PA system too....just run them hi-hats and HF knobs hotter [] (blasphemy I know, but you gotta do what you gotta do sometimes) I would take lack of beaminess for a failing HF response any day of the week in a PA. Quote Link to comment Share on other sites More sharing options...
lorcoll Posted February 16, 2006 Author Share Posted February 16, 2006 Excuse me but what is a "CD horn"? Can anyone explain me the meant of this word? Thanks. Quote Link to comment Share on other sites More sharing options...
ajsons Posted February 16, 2006 Share Posted February 16, 2006 Directivity A horn provides more sound pressure level (SPL) at a given listening area by increasing the directivity of the sound towards the listener. There is more sound at the listening area, and less sound outside of that area. By analogy, think of focusing a beam of light (from a flashlight or torch). A widely focused beam spreads the light around, reducing the intensity at any one point. However, a narrowly focused beam provides much more light intensity at the center, and much less in the surrounding area. Consider a point source speaker driver hanging high up in the air. Sound will be radiated off in all directions. Now if we sit the driver on the ground, it has only half the area to radiate into, and acoustic power will be increased by two at any position. If we place the driver at the corner of a floor and a wall, we now radiate into quarter-space, and SPL is increased by four times. Likewise, a driver in a corner will be constrained to one-eighth of the free space area, and SPL is eight times louder. Each of these increases the directivity. A horn increases the directivity of the compression driver, providing increased SPL in a certain area, over the frequency range for which the horn is designed. The "certain area" is actually a cone with a particular cross-sectional shape and angles describing the spread of the cone away from the driver. Round horns produce round cross sections with a constant angle of spread (for a given frequency). Radial horns have two angular components: a vertical and a horizontal spread. Often the vertical angle is small (compromised) so that the horizontal angle can be large (covering a wider area for an audience in a horizontal plane). However, round horns and radial horns tend to change their angles of spread (their directivity, measured by the directivity index, or DI) as the frequency changes. This means that high frequencies, for instance, might be more highly directed, and therefore sound louder to someone in a central location than to someone else outside of the center (but still within the horn's low-frequency area of enhancement). To cope with this problem, the constant directivity (CD) horn was invented. The CD horn provides the same SPL at all frequencies within the designed coverage angles. http://melhuish.org/audio/horndriver.html'>(The above is from the internet). Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 16, 2006 Share Posted February 16, 2006 CD = constant directivity The flare rate of the horn is such that the dispersion is identical at every frequency....the end result is a slowly decaying HF response (around 12db/octave if I remember correctly). Typically a corrective EQ is applied to regain a flat response and the end result is very even coverage. CD horns are most often implemented in PA applications where even coverage is vital to a good show....also the extra circuitry doesn't hurt the sound because you're most likely already using some EQ. Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted February 16, 2006 Share Posted February 16, 2006 well said, gents. I'm gonna see if I can dig up a pair of these. I think I know of a pair. Michael Quote Link to comment Share on other sites More sharing options...
lorcoll Posted February 16, 2006 Author Share Posted February 16, 2006 Thank you very much for the perfect explanation. But my question now is: is the SM-120 a CD horn? Can it sound better than the K400 (what the sonic differences)? Or have I lost my money for it in a home use? Lorenzo. Quote Link to comment Share on other sites More sharing options...
Dan1045 Posted February 16, 2006 Share Posted February 16, 2006 CD = Constant Directivity Dan Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 16, 2006 Share Posted February 16, 2006 Thank you very much for the perfect explanation. But my question now is: is the SM-120 a CD horn? Can it sound better than the K400 (what the sonic differences)? Doesn't look like a CD horn but the spec. sheet above certainly says it is. Shawn And I'll add that the polar plots look like that of a CD horn too... Will it work well as a squaker? I'm not sure. In the frequency range you're using it, I would bet that you're down about 3 or 6dB around the crossover point to the tweeter. One thing you could experiment with is different crossover slopes between the squaker and tweeter....like run the tweeter at 24db/octave and the squaker at 12dB/octave, which with the natural rollow will be 24db/octave matching that of the tweeter. Or heck, run the squaker wide open and do a 12dB on the tweeter. Aren't the stock cornwall type B? crossovers that way anyway? Quote Link to comment Share on other sites More sharing options...
djk Posted February 17, 2006 Share Posted February 17, 2006 With an EV 1823 driver, the SM120 requires about 6dB of attenuation to match a LaScala. You then run a cap in series with an inductor to remove the attenuation at the crossover point. This provides 6dB of boost right where you need it, and then the horn/driver combo rolls off rapidly with no additional crossover components. It sounds quite good with a LaScala, much better than a K400 for home use. The K400 had better 'throw' for long narrow rooms. The EV Sentry III studio monitor used this horn, it looked similar to a Klipsch Belle for cosmetics. They show up on eBay frequently, and not too expensive. I have a pair new in the box that I plan on making a Belle clone with (someday). Quote Link to comment Share on other sites More sharing options...
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