sunnysal Posted July 30, 2003 Share Posted July 30, 2003 and the problem with the belle is its limited bass response versus the k-horn....oh well. I too saw BF's article, promising. re: the bumps at 5 and 7mhz, well those notch filters may not be ideal but they have been quite popular tweaks on Klipsch speakers for a while, especially the 9khz notch filter for the k-horns. Keep us informed as you wade into the Klipsch issues. I bet your Chorus' will sound great with your amps! what will you run them on? regards, tony Quote Link to comment Share on other sites More sharing options...
artto Posted July 30, 2003 Share Posted July 30, 2003 Hey Lynn. Thanks for posting the rest of that Journal of the Audio Engineering Society article. Quote Link to comment Share on other sites More sharing options...
111db Posted July 30, 2003 Share Posted July 30, 2003 Lynn, You're a Laurie Fincham associate/disciple?..... We're not worthy! (genuflecting) Now that's off my chest, I would like to recommend that before you try to correct the wee prominences in your Chorus response with major surgery or filters, you might try damping the horns, which are pretty ringy as supplied. Most tweakers here use "rope caulk", a moldable weatherstrip cord product available at home centers. I'd be REALLY interested in before-and-after measurements on that tweak, as I own Fortes which use essentially the same horns. I have recently struck up a friendship with a former Klipsch employee who is still associated with the OEM which manufactures most of Klipsch's HF drivers. He is going to be sending me some alternative-material diaphragms (titanium, aluminum)for my Forte horns. He is really big on the sound of the aluminum diaphragms over the stock polyetherimide, though he says they tend to fatigue over time if driven at really high levels (which I NEVER do, oh no!). He says that the titanium ones ring too much, and that titanium is only in wide use because of marketing hype and because the ringing sounds sizzlin' good to some people. If and when I get these I may send them your way for some measurements, if you're game. Since you obviously like the Chorus, you will also have to look up some Fortes to audition. Many consider them the best in the Chorus/Forte/Quartet family. Significant bass extension below the Chorus due to higher cab-volume/driver-size ratio. You'd be welcome to audition mine if you're anywhere near Colorado, though I'm guessing you're from the Isles. Welcome to high efficiency heaven! Don ---------------- On 7/30/2003 1:09:41 PM LynnOlson wrote: By the way, my current project is smoothing out the top end of the Chorus I mid horn - it has a pair of bumps at about 5.5 and 6.8kHz that are 5dB high. I'll be measuring Gary Dahl's Chorus II's (which arrive on his doorstep today ) and see if the Tractrix does the same thing. If not, then I decide between woodwork on the Chorus I or a notch filter added to the crossover. Back in the bad old days of Audionics, I made notch and inductance-correction filters for each driver even before I did the high and low-pass filters, so that would be nothing new for me. But I also remember there's no free lunch in speaker design - even the most skillful notch filter subtly degrades transparency and the sense of "directness", so you have to avoid over-equalizing the speaker. ---------------- Quote Link to comment Share on other sites More sharing options...
LynnOlson Posted July 30, 2003 Share Posted July 30, 2003 The measurements you see were made *after* the rope caulk was installed on the mid and tweeter by my good friend Gary Dahl. I'm not too sure the horn damping affects the measurements that much, although there certainly was a gratifying subjective improvement in high-level dynamics and freedom from grit-n-grain. But a fair amount of forwardness remained, so I dusted off my old MLSSA system and measured what the speaker was doing. Raw MLSSA data requires a degree of interpretation: for one thing, the measurement window was about 7mSec long, which means frequencies below 300Hz are not accurate. Also, to my chagrin, I haven't chased out a DMA timing problem in the host computer, so the upper freq limit was a feeble 10kHz (the ACO Pacific 1/2" condenser mike is good to at least 25kHz based on earlier measurements). When I visit Gary Pimm in Portland, Oregon, this week he'll help me chase out the DMA problem so I can get full bandwidth out of MLSSA again. The deep notch at 6.3kHz had me thinking the tweeter was out of phase, but reversing the phase merely moved the notch down 500 Hz, with no change in overall depth. The 6kHz region obviously has a rapid phase rotation between the two drivers. Disconnecting the tweeter removes the 3rd bump at about 8kHz, but the two lower freq ones remain at the same amplitude, so the source is obviously the mid horn. When I return in a few days with a full-functioning MLSSA, I'll measure Gary's new-arrival Chorus II's (they just got in this afternoon) and see how the 5kHz-and-above region looks. Different, I'm sure, with different drivers and a slightly different crossover. Aside from the arcana of this MLSSA display, yes, I spent a couple of days at KEF and the BBC research labs some time in 1975. Charlie Woods, Gene Still, and myself were promoting the Shadow Vector Quadraphonic decoder I invented and licensed to Audionics, but I don't have to tell anyone that multichannel was about twenty years ahead of its time. Between the sales/technical pitch getting the Brits interested in SQ (they weren't), I picked up a lot of hints from Laurie about Target Filter Function design and other goodies. Mostly, I was jealous of his $200,000 DEC minicomputer and full-time FORTRAN programmer on loan from a local technical college. No way was an outfit like Audionics going to spend anything more than a few thousand bucks on test gear, and I wasn't exactly a whiz at programming (HTML and Emacs is about my limit). I am very very appreciative that first MLSSA, then soundcards + MLS software can outperform KEF's fancy-fancy setup back then. When I got back to Audionics, I had to struggle with an Altec 1/3 octave real-time analyzer and dinking around with square-waves and a scope. Very crude, missed a lot of data, you had to do a lot of swooping around with the microphone to get an idea of the polar pattern and soundfield. Quote Link to comment Share on other sites More sharing options...
g3dahl Posted July 31, 2003 Share Posted July 31, 2003 As Lynn said, my Chorus II's arrived this afternoon! I unpacked them, hooked them up, and sat back for a quick listen. Oops, no sound from the left mid. Took out the driver for a look. Measured 11.4 ohms across the terminals, hmmm. Disassembled the unit and inspected the diaphragm. Looked fine. Put it back together and did a battery test. CLICK! Okay, the driver's fine. Took out the crossover...ahh, there it is. One of the wires from the autoformer was broken just above its pad on the board. As long as I had the crossover out, I went ahead and replaced all the caps with Hovlands, Auricap and North Creek (Lynn didn't mention this but I did the same to his, and yes, it improved the sound). Put everything back together and put on some more music. YES! That's more like it! My wife came in to see how things were coming along. As she sat down in the sweet spot, she commented -- are you ready for this? -- "Oh, they're smaller than I thought." After a brief listen, she was smiling. She likes them already! Anyway, the Chorus II's are off to a good start. I could hear some peaks in the treble, fairly similar to those in Lynn's Chorus I's, and the speakers are voiced to about the same tonal balance. If we can get things flattened out a bit, we'll be in for a real treat! By the way, my wife has previously put up with Altec Voice of the Theatre, Altec 604's, Edgarhorns and Exemplars all being in the house at the same time! Of course we lived in a bigger house back then...the Chorus II's are plenty big for my room. Besides, they need some room to grow, because I'm going to top them with Altec 311-60 horns with 290 drivers! That'll be another thread though... Gary Dahl Quote Link to comment Share on other sites More sharing options...
sunnysal Posted July 31, 2003 Share Posted July 31, 2003 Lynn, Gary, I can tell you we will ALL be looking forward to hearing about the results of your testing and tweaking...to bad for me it will all me to optimize Chorus I and II's ! LOL perhaps I should send you a pair of k-horns to play with and hang back and wait for the results! Warm regards, tony Quote Link to comment Share on other sites More sharing options...
LynnOlson Posted July 31, 2003 Share Posted July 31, 2003 Don't worry, Gary and I will pop up again with our results, and will post lots of MLSSA data and crossover mods as we go. I'm a newbie to true high efficiency, but still have my old BBC/KEF/Quad design preferences, and like to equalize speakers to flat-to-mildly tilted towards the bass (about 1dB tilt from 100Hz to 10kHz). My degree is not in engineering, but perceptual psychology, and you almost never encounter an acoustical environment in nature that tilts towards the treble. Instead, the moisture in air absorbs treble at distances more than 20~30 feet, so we hear distant sounds as rolled-off and with multiple reflections, and mentally correct the timbre for distance. This is the acoustic equivalent of distant mountains being low-contrast and bluish; the scene would look weirdly unnatural if distant objects were reddish and high-contrast. So I apply the "error budget" of the speaker in a direction that is consistent with sounds we hear in the real world ... very mild treble attenuation is preferable to peaking, which is rare in most environments. Peaking and resonances are more characteristic of artificial sound, and some listeners don't mind, but others do. But I've learned the hard way that speakers are very easy to over-equalize, and every crossover component exacts a price in transparency and coloration - capacitors being the worst offenders of all. Sure wish I could buy 6.8uF Teflons! I really admire the consistent philosophy of the Klipsch speakers over the decades - steady attention to basic engineering principles and getting IM distortion as low as possible. Now that amplifier design has undergone a deep re-think in the last decade, we can hear just how good Klipsch has been all along. If the Brook PP 2A3 were brought back today and auditioned with the Heritage line, I think both the SETs and the PP-pentode folks would be astounded at what they heard. Part of the reason I bought the Chorus I's was really hearing the Aurora for the first time at Charlie Kittleson's place - they really are incisive speakers, and reveal a great deal about the amplifier. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted July 31, 2003 Share Posted July 31, 2003 Amen! And that is the main reason I went for my 2A3 PP amp, which is quite similar to the brook...what a combo with my k-horns! It will be interesting to see what, if any, mods you make on your amps after auditioning them with the Klipsch to optimize them for the high efficiency speakers. Brook had a special K-horn version of its 10A (edit: whoops I meant 12A) you know. regards, tony Quote Link to comment Share on other sites More sharing options...
Deang Posted July 31, 2003 Author Share Posted July 31, 2003 Lynn and Gary -- you guys are the bomb. Lynn -- Maybe we should just put a few trees in front of our speakers. Quote Link to comment Share on other sites More sharing options...
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