rongon Posted August 2, 2011 Author Share Posted August 2, 2011 More experiments! Last night, I stopped at Home Depot and bought another few pounds of Duct Seal. Coated the KG4.5 woofer frames, following the method of planet10 from over at DIYaudio.com. [ http://www.diyaudio.com/forums/full-range/111724-extreme-basket-tricks.html ] The result? SUCCESS! The KG4.5 woofers have stamped frames (i.e. cheap). Remove a woofer from the cab, hold it from its magnet and tap on the frame, and you'll hear a distictive "bong" sound, like the sound of a poorly made bell. It sounds like it's in the 500 Hz range and has a decent amount of sustain. Not good. Once again, a coating of Duct Seal removed that problem. Rap on the frame now and all you get is a dull "tink" sound, with just a little hint of ring left. After putting the woofers back in, I hear a marked reduction in upper mid sibilance. Why would damping the resonance of the woofer frame improve the subjective performance of the tweeter? Ya got me... But I'll take it! The upper bass/lower midrange now sounds more full, maybe a little warmer. That same region also sounds more clear, less muddled. This is the biggest improvement so far. Now that I've damped both the woofer frame and the tweeter's plastic horn, there is a big difference in how the upper notes on a piano and orchestral bells sound. Before the Duct Seal treatment on the tweeter, bells sounded very ring-y and startlingly lifelike, even exaggerated. After the damping, they sound more "accurate," or more like I've heard from good cone 'n dome speakers (i.e. not as loud). I'll guess that the undamped tweeter horn rings a bit, which adds some extra zing to the 5 to 10kHz region, and that this has been toned down by damping the horn. While I am very happy with the reduction in perceived sibilance on vocals and the greater accuracy of reproduction of jazz ride cymbal, I kind of miss how orchestral bells used to "pop" to the front of the mix. I listen to lots of jazz, so any obnoxiousness in reproduction of jazz ride cymbals cannot be tolerated. I might get around to removing some of the Duct Seal from the tweeter horns, just to see if I can find a pleasant compromise between "zing" and "accuracy." We shall see... I've read a few threads with pictures of the RF-7 and some other Klipsch crossovers. I see they all use film capacitors. While they don't use anything exotic, the stock caps look like decent-quality metallized mylar. Nothing wrong with that. My experience with cap replacements has been that you'll only get a huge difference when changing capacitor types, such as when replacing non-polarized electrolytics (usually wretched sounding) with good quality film caps. Going from decent mylar film to top-shelf polypropylene usually yields more subtle results. Usually you'll get a little better clarity, a little smoother highs, maybe a little less "grain" in the sound. More of a tweak than a make-or-break change. This Duct Seal experiment has been more than that. It has made me want to keep these speakers. They now sound quite acceptable. I could not enjoy the KG4.5's in their stock state -- too much harsh sibilance and confused lower mids -- but now they're a nice pair of budget speakers that are more efficient than anything else I could get in their price range. Now to the RF-3's. Their problem is a completely unacceptable level of harshness in the upper mids to lower trebles. If I can tame that, then they'll be even better than the KG4.5's (the RF-3's are more efficient and have tighter mids and bass response). First, though, I need to figure out how to get the drivers out of the box, without damaging anything. Wish me luck... -=|=- PS -- I listened to "Solar" from Bill Evans Trio "Sunday at the Village Vanguard" (Analogue Productions SACD). Paul Motian's drums nearly leap out of the speaker. Amazing. The drumset sounds big as life, with just a weenie little 6 watt per channel amp driving. This is great sound for only $250 in speakers. [] Quote Link to comment Share on other sites More sharing options...
rongon Posted August 3, 2011 Author Share Posted August 3, 2011 I got the chance to take a quick listen to a pair of Tangent 400's this evening. I'd been listening to my newly ductseal-dampened KG4.5's before I went to hear the Tangents. First, I did a quick comparison between the KG4.5's and my Tannoy T185's. The KG4.5 sounds more wide-range, with more sparkle on the highs, but the KG's have a recessed midrange, like a "high-fi salon" sort of tonal character. Fortunately, the KG4.5's are way more dynamic and clear in the mids. and less "tizzy" in the highs. They do sound pretty good. The Tannoy's just sound like a more expensive speaker (which they are). There's a relaxed, smoother quality to the Tannoy's, especially in the all-important mids. The KG4.5's sounded more "hi-fi showroom" to me. Right now, I'm liking the Tannoy's sound more. Maybe bracing the KG4.5 cabinets will increase midrange clarity. I also noticed that the difference in sensitivity between the Tannoy T185 and Klipsch KG4.5 is only one click of my volume control (2dB). The Tannoy T185 is rated at 91dB/1W/1m, anechoic. The Klipsch KG4.5 is rated at 95dB/1W/1m "in room." Judging by the difference between T185 and KG4.5, I'd say the KG4.5 would be more accurately rated at 93dB/1W/1m. I was hoping the Tangent 400's would leap out at me and say "Buy me!" When I got there, I saw that they were in kind of rough shape. The drivers all look pristine, but the grill frames were broken (although still usable) and the cabinets were in just so-so shape, with plenty of small dings and scratches. It didn't help that the Tangent cabs are not very good-looking to start with. They look cheap. There was only the headphone jack from a laptop PC to use as a CD player, and a black Denon receiver of some kind. Nice-looking speaker wires, though. Looked like braided teflon-jacketed wire of some kind. Might be that aviation grade, silver-plated, mil-spec stuff. I played my usual selection of speaker-testing music. Cassandra Wilson, Mahler and Cannonball Adderley/Miles Davis. I never got to Bill Evans. From the first few notes, I was reminded of my previous experience with Heresy speakers many years ago. Lots of midrange detail and lots of big dynamics, but a very forward, aggressive presentation. On top of that, there were obvious box colorations. The Tangent cabinets are downright cheap 'n nasty. Rap on the sides and it sounds like a big, hollow wooden box. Not a good sign at all. The cabs are quite light. I had no trouble at all moving them around. They feel lighter than the RF-3's. The forward mids (woofer to mid horn crossover region?) and the hollow box resonances were driving me crazy. No way I could live with those. Some really good points, but some really frustrating bad points. I didn't buy them. Hopefully I'll get to play with the RC-3's this weekend. -=|=- Quote Link to comment Share on other sites More sharing options...
chisoxpurdue Posted August 4, 2011 Share Posted August 4, 2011 The Tangent 400s are ported Heresys. The same components as Heresy 2s if I recall. I have the 500s, which have a passive radiator instead of ports. Obviously, the cabinets need work. That is the next major project for me. I am building new cabinets for the Tangent 500s. I have heard some mention you could brace and reinforce the cabinets. I am just building new. I think they can shine with the right work. I know most do not want to build cabinets, but it is an option. What price were the Tangent 400? Quote Link to comment Share on other sites More sharing options...
rongon Posted August 4, 2011 Author Share Posted August 4, 2011 I'm not sure I want to take on a (physically) large project right now. I'm also a miserably bad woodworker. Pathetic. ------------- The speakers are $300 for the pair. The cabs are in reasonably good shape, just some corner dings, scratches, dusty, etc.---------- What about the honky, forward midrange colorations? Do you think that's all bad cabinet resonances? Quote Link to comment Share on other sites More sharing options...
chisoxpurdue Posted August 4, 2011 Share Posted August 4, 2011 Thats a little high due to the work you would have to put in. They are worth that to part out though I think. Now my type of thing. Quote Link to comment Share on other sites More sharing options...
Ironsave Posted August 4, 2011 Share Posted August 4, 2011 For $300 you could do better. If they were pristine; I would say it would have been a pretty good deal. (My Heresy Is were $250; roughish cabinets; but I patched missing veneer and lightly sanded and oiled the hell out of them). The Heresy I cabs are solid compared to the Tangents. Chisox; when you get around to doing the cabs; I would love to see....... [] Rongon.... Good Luck on the RF3 experiments! Quote Link to comment Share on other sites More sharing options...
chisoxpurdue Posted August 4, 2011 Share Posted August 4, 2011 I will definitely post pics. I do not know how long I will be near Chicago though. Hopefully a job offer is on the near horizon. They are putting together and offer in the next week or so. Quote Link to comment Share on other sites More sharing options...
rongon Posted August 13, 2011 Author Share Posted August 13, 2011 I applled another tweak to the KG4.5's that I think is worthwhile. The duct seal tweak really helped. The mids became much clearer. But the high frequencies were still just a bit "hot" sounding, a bit harsh. Enough that it's been bothering me. I was reading about impedance curves and their influence on the frequency response from a speaker driven by a tube amp with relatively high output resistance. Since I'm using a tube amp that I'm sure has a relatively high output resistance, I figured I'd better see if the harsh highs I was hearing could be toned down with a compensation network (crossover tweak) of some kind. One idea is to put a resistance in parallel with the driver's impedance. The tweeter driver's impedance likely has two pretty major peaks, one at the crossover point, and the other up high where the acoustic response begins to roll off. In theory, since two resistances in parallel are reduced in value by R1*R2 divided by R1+R2, the basic impedance of 8 ohms shouldn't be changed much, but large peaks of something like 100 ohms or more would be reduced by a lot. In my example, let's say we take a 50 ohm resistor across a speaker with nominal 8 ohm impedance and DC resistance of 5.5 ohms: 50 * 5.5 = 4.96 ohms will be the new DCR of the driver+resistor. That's probably not too bad. Let's say the driver has an impedance peak of 100 ohms at a certain frequency. 50 * 100 = 5000 50 + 100 = 150 5000 / 150 = 33.33 So we've reduced that 100 ohm impedance peak to about 33 ohms -- In theory, at least. I started by putting a 50 ohm 10W wirewound resistor across the + and - terminals of each speaker, just to hear what would happen. Bingo! Smoother highs. The downside? Wasted power. The amp couldn't go as loud with the resistors there. So I took out the tweeters and tacked in the resistors across the + and - terminals of the tweeter itself. I figure the HF section of the crossover will isolate the resistor from the woofer, and that should allow the amp to drive the woofer more directly. I then wired in the resistors and put the tweeters back in the cabs. Result? Well, with 50 ohms the tweeter sounded a little 'closed in', maybe a touch too mellow. So I took out those resistors and put in 100 ohm 10W wirewounds. The effect of these resistors is pretty subtle, but I think I've found a good compromise between brightness/harshness and easy-on-the-ears. The 100 ohm resistors round off the harshness just enough. The best (proper) way to accomplish this would be to put a Zobel network on the tweeters, basically a resistor and capacitor in series, wired from the + to - terminals of the tweeter. The resistor would be a little more than the DC resistance of the tweeter (probably 7 ohms), but the capacitor has to be calculated using the voice coil inductance of the tweeter. Do you think the folks at Klipsch would be able to tell me the voice coil inductance of these tweeters? At any rate, I was just listening to the system this morning, playing a nice, mellow Denon CD by swing legend Papa Jo Jones, with Hank Jones on piano.... Also a gold CD pressing of Bill Evan's "Interplay." It's all sounding pretty darned good to me. These are the best $250 speakers I've ever had. I think I'm beginning to see what makes you Klipsch fanatics love these things so much. I have a friend who made a line array out of Jordan full-range drivers, with a couple of Jordan woofers down low and Raven ribbon supertweeters. It's the most high-resolution, dynamic speaker system I've heard so far. Sweet sounding but fast, quick and dynamic, and not fatiguing or harsh in the slightest. Holographic "you are there" imaging that just won't quit. The cost? Each of his 24 (12 per side) full-range drivers cost $150 or so. Each of his 4 woofer drivers cost at least $200. Each of the 4 ribbon tweeters cost over $200. Then he had cabinets made. This is just waaaaay out of my financial reach. No way. I heard another guy's system with a beautiful EL34 amp into Wilson WATT/Puppy speakers. You know, those pyramid shaped things on top of 100 lb dual-woofer cabs. It sounded great, but had that "hi-fi salon" sound. Polite. Recessed. Really good, but not exactly my cup of tea. Oh yeah, and they cost over $10,000. Again, no way am I getting anywhere near that. OK, so I come home to my humble listening system, to my $250 Klipsch KG4.5's and my homemade triode amp. You'd think it would be put to shame by such expensive systems as I just heard. You know what? It sounds good. I get great dynamics, really quite good clarity, solid imaging, bass that goes low enough, and with my tweaks, all that clarity and speed with no listening fatigue. For $250, no less. KG4.5 + some simple tweaks = great budget speaker for flea-power tube amps. I'm now a happy Klipsch owner. Gotta save up for a pair of Forte II's or Chorus II's with the tractrix mid horn. Or maybe a pair of Altec 19's. And I haven't even started on the RF-3's yet. See what you've done! [] -=|=- Quote Link to comment Share on other sites More sharing options...
rongon Posted August 15, 2011 Author Share Posted August 15, 2011 So, after deciding I was liking the newly altered KG 4.5's, yesterday I switched back to the Tannoy speakers and gave them a fair hearing. I put the Tannoys in a better location than before, more in line with where the KG 4.5's have been. The results? - Tannoys are less efficient than the KG's (KG's play way louder before breakup) - Tannoys are smoother sounding, less intense than the KG's - KG's have bigger bass, but not as tight and controlled - KG's have a sort of "sizzle" that rides over the highs, all the time. Can get irritating. - Tannoys don't seem to go as high up in frequency response as the KG's. But they are smoooooth. - Both are very clear sounding, lots of detail and great imaging. Once again, I'm impressed with how well the KG's can compete with the Tannoys, which cost an awful lot more when new. I think the amps need to be voiced for the speakers. The KG's need a really mellow amp with a laid-back high frequency presentation. The Tannoys need an exciting amp, with a more intense, zingy high frequency presentation. So it boils down to a question of taste. But it's been fun improving the KG's. They respond to tweaks very nicely. -- Quote Link to comment Share on other sites More sharing options...
rongon Posted December 10, 2011 Author Share Posted December 10, 2011 Hello again... I'm finally moved in at my new place, and have had some time to play with speakers again. I got a pair of the Crites upgrade titanium tweeter diaphragms for my KG 4.5's, and finally put them in a couple of days ago. The verdict? A lot of the problems I mentioned with sibilance and a sort of "sizzle" over the highs have been fixed. The highs are most definitely smoother with the titanium diaphragms. The combination of the duct seal damping of the woofer baskets and tweeter horns, and now the titanium diaphragms, has all really smoothed out the KG 4.5's sound. I also scored a pair of stock KG 4.5 crossovers from ebay. I'll use them for experiments with capacitor transplants. My plan is to find mellow, smooth sounding caps for the 4.5's. I have a few paper-in-oil 0.22uF caps I can use for bypass. I recently lucked into a pair of Snell Type J/III in very good shape. Even the foam surrounds on the woofers are intact. These Snell speakers are supposed to be easy to drive for weenie triode amps like mine, and so they have proven to be. The Snell Type J/III's are rated at 91dB/1w/1m, which is the same as the Tannoy T185. I played them both side-by-side, and they are very close in level, and actually sound quite similar. The Tannoys have a bit more "shout" to their midrange (horn sound?) and definitely go lower, while the Snells have a bit more depth to the midrange imaging and more sparkle and "air" in the treble. At this point, I like the Snells an awful lot. They are surprisingly dynamic, definitely the most "jump" I've heard from a cone-and-dome system. (I should point out that the Type J/III's tweeter is a silk dome with partial horn loading, so we're still not completely in AR/KEF/B&W territory.) By comparision, the KG 4.5's w/ duct seal and titanium tweeters have a more "scooped mids" sound, with a treble sheen and fat bass, and lots of dynamic "jump factor." The KG 4.5 plays noticeably louder at the same volume control setting on the amps than either the Tannoy or the Snell. Definitely higher efficiency, and definitely a more aggressive sound. I briefly listened to the RF-3's, when I first moved in. They still throw out gobs of detail, but still sound "hard" and harsh in the mids. Kind of a fatiguing speaker at this point. I haven't spent any time on them as of yet... So I now have a whole menagerie of pretty decent speakers to play with. Right now the Tannoys are taking a rest, while the Snells are in my living room system driven by the push-pull 2A3 amp, and the KG 4.5's are in the bedroom being driven by a push-pull, triode-wired EL34 amp, which puts out a whopping 10 watts per channel. The KG4.5's sound really good in that room, although they're still a bit bright. But they are a lot smoother sounding than they were with the polymer diaphragms in the tweeters. The Crites tweeter upgrade is a huge success. I'm hoping they continue to break in over the next few days. -=|=- Quote Link to comment Share on other sites More sharing options...
rongon Posted January 3, 2012 Author Share Posted January 3, 2012 A further update... I'll call these modified KG 4.5's the "KG4.5ti" (titanium diaphragms from Bob Crites added). The KG4.5ti's are back in the living room. The titanium tweeter diaphragms needed to break in. I added some felt around the perimeter of the tweeters, hoping to break up any baffle diffraction modes. That helped, noticeably. I couldn't get all the way around the drivers because of the way the grilles fit on the baffle. I did what I could. The result? Upper mids got a bit more forward, but noticeably clearer. - I'm now getting better imaging from these speakers. It's really quite enthralling. - I'm also getting beautiful highs (a big change!). I played a 1987 Denon CD of Ravel orchestral stuff (Ma Mere L'Oye and Pavane, etc.). It's a minimalist recording, mostly relying on an X-Y pair of mics for stereo. On my other speakers, this recording sounded kind of murky, not detailed. Some things would poke out of the mix here and there, but a general murkiness prevailed. With the KG4.5ti, the imaging is very precise and clear, with percussion popping out at you, much like it does in a real-life concert hall. The faults are still there, but less aggravating. - You have to treat these speakers like giant headphones. There is one, and only one, proper listening position. Go off to either side and the soundstage disappears. I guess Tractrix horns have a relatively narrow, controlled dispersion characteristic. - The upper mids and highs still have an "etched" quality to them, sort of "electronic" (a friend of mine called it "shouty"). It's better now after the titanium diaphragms and felt baffle treatments, but it's still there. I think that's the "horn sound." - The mids are still a bit recessed, but I'm sitting near-field (about 5 feet away), so that's actually a blessing. Could be a problem in a bigger room. - Voices tend to sound a bit "confused," kind of like how they sound out of a PA system. There's a resonance somewhere around 1kHz that needs to be damped. Possibly woofer cone break up modes. Dunno. - The bass is still on the loose and boomy side. I'm going to a crafts store to get sheets of wool felt to stick on the inside walls of the cabinets. I'm hoping to lose some midrange glare from box resonances, and maybe tighten up the bass a little. I now have over $300 in these speakers, but I have to remind myself that this is downright cheap for the sound they give. I'll bet an internal brace from front baffle to back wall would help a lot. -=|=- Quote Link to comment Share on other sites More sharing options...
rongon Posted January 4, 2012 Author Share Posted January 4, 2012 More fun today. I went a little crazy at Walmart -- bought six packages of their craft felt (polyester felt) with peel-off adhesive backing. Lined the insides of the KG4.5ti's with it. I could immediately notice a reduction in a nasal-sounding ring that was in the box resonance. Put back the drivers and the foam (stuffing), but kept the foam up more toward the tweeter end of the box, letting the air move between the woofer and the port. The result? Well, there was an obvious increase in midrange clarity. Much less mud. That's the good part. The bad part was that the tonal balance went from the stock "plump" to more "lean" or "thin." To test to make sure the speakers still make bass, I played the old Telarc CD of Stravinsky's Rite of Spring (Cleveland Orch., Lorin Maazel conducting). Oh yeah, these speakers make some serious bass! WHAM! SLAM! No problems there. The bass is now more damped, much better controlled. The woolly bass I was complaining about is now totally tight and fast. So, tighter bass and clearer midrange. That's all good. Really good, actually. I was thinking of selling these KG4.5ti's to a friend, but now that I've done all this, I'm having second thoughts. Unfortunately, the tweeter still has that "electronic" edginess to the high frequencies I was complaining about. As far as I'm concerned, that's the last major fault in the speaker. I think I want to reduce the tweeter level by a hair, maybe 2dB. Any ideas how to do that? Here's the KG4.5 schematic: According to the speaker design books, I'd put an L-pad right before the tweeter, after the crossover. After the 3uF cap to the tweeter "+" terminal would go a series resistor. Then something like 100 ohms between the + and - terminals of the tweeter. I guess I'll go find that book and try to figure it out. Been listening to these speakers all day, switching back and forth to the Snell's. The Snell's are warmer, and have a nice way with acoustic instruments. But they sound polite and small compared to these modified KG4.5ti's. The Klipsch's have more slam, go louder, play tighter bass and have every bit as clear a midrange now. The Snell's only clearly win in the high frequencies. The silk dome tweeter is very smooth. The KG4.5ti treble is "harder" and gets to be a bit much. So before delving into crossover mods, I tried an easy "fix" for the KG4.5ti's. I took a sheet of polyester batting (a Christmas decoration "snow blanket" actually) and lined the backside of the grille cloth with it, in front of the tweeter only. It actually sounds quite nice this way! The highs are tamed. Maybe a little too tame. But only by a hair. It's funny, I'm right back where I started, trying to tame the tweeters. But the speakers are performing at a whole 'nuther level now. They don't sound cheap at all. Very, very clear and fast. -=|=- Quote Link to comment Share on other sites More sharing options...
t-man Posted January 4, 2012 Share Posted January 4, 2012 Try an EQ? Quote Link to comment Share on other sites More sharing options...
rongon Posted January 5, 2012 Author Share Posted January 5, 2012 Try an EQ? No, that adds more electronic hooey to the signal chain.... and the speaker crossover is already an equalization circuit. Even if I had the money for a truly transparent sounding digital EQ, I'd still rather buy better speakers first. I think eight Mark Audio Alpair 7's would be nice, and have someone make ported cabinets for them. Or biamp with a pair of Alpair 7's run from a triode amp and cross over a pair of mono subwoofers below 200 Hz or so. That would be if I had a lot of money around. These fairly inexpensive KG4.5's have been a great way to learn. I believe the 1980s - '90s mid-line Klipsch speakers have hidden potential, but it takes some "DIY" work to get the most out of them. I also think the Klipsch "house sound" tends toward a "hot/bright" treble. Fortunately, they're efficient enough that taming their response a little will still leave a relatively high-efficiency system in place. I'm comfortable losing a decibel of efficiency to get a more relaxed sound out of them. My next step is to add a fixed L-pad attenuator network across the tweeter terminals. A series resistor of 1 ohm and a parallel resistor of 50 ohms should yield a drop of about 1.5 decibels. I'm hoping that the tweeter actual impedance is close to its 8 ohm nominal impedance. If not, it will change the crossover point of the high-pass network, and we'll see if I can hear it. Oh what fun... -=|=- PS - Does anyone have impedance, voice coil inductance specs for the K-85-K tweeter? (I can measure the DCR, but my cheap LCR meter has bitten the dust.) -- edit: I measured the DC resistance with a DVM, and it shows 8.1 ohms. That's pretty high! Usually the DCR of a nominal 8 ohm speaker will be about 6 ohms or so. Is the K-85-K horn tweeter more like an 11 ohm driver? Or should I treat it like an 8 ohm driver? PPS - A friend of mine once had a client with a pair of La Scala that he thought were a little harsh sounding in the highs. My friend replaced the original EV T35-type tweeters with Raven ribbons. According to the client, bliss followed. I should point out that La Scalas cost just under a grand on the used market, and those Raven tweets cost a few hundred dollars *each*. So far, I'm in for about $350 with these KG4.5ti's. That's a big difference. -- Quote Link to comment Share on other sites More sharing options...
rongon Posted February 7, 2012 Author Share Posted February 7, 2012 I finally got these KG 4.5 beasties to a state where I like them. After much consultation with people who know a lot more about crossover design than I do, it became apparent that the original KG4.5 crossover is a truly strange design. --------------- I bought a spare pair of KG4.5 crossovers on eBay that turned out to be very different from the ones in my speakers -- even though they say "KG4.5" right on the circuit board. These later-version crossovers are the exact same as the KG5.2 crossover, but with a 33uF NP electrolytic in the woofer circuit instead of 28uF. The KG5.2 is a more normal-looking circuit. The 5.2 uses the same Tractrix horn and tweeter as the KG4.5, and the woofer circuit is identical between the KG4.5 and KG5.2 crossovers. So I swapped in these newer-version KG4.5 crossovers, and instantly heard that a "hhhhhhhhhhhhhhhh" coloration had gone away. The tonal balance is similar, maybe a bit more laid back in the upper mids with the newer version crossover. I think the verdict is that the original KG4.5 crossover has some seriously weird flaws. Replacing it with this undocumented later version crossover has helped things a lot. Quote Link to comment Share on other sites More sharing options...
t-man Posted February 9, 2012 Share Posted February 9, 2012 Interesting. I've also found that there are several important variations in how they built the cabinets within the KLF 20 short run. I suppose there may be more and more variations with speakers of the same model than we may think. Quote Link to comment Share on other sites More sharing options...
Ironsave Posted February 16, 2012 Share Posted February 16, 2012 Congrats. Nice to see your persistance has yielded dividends. I had a set of the KG 5.2s. They were capable of incredible volume; they could knock things off shelves. They could do this while still sounding clear and were GREAT speakers. I sold them in favor of my Heresy Is; and miss them, but would make the same choice in a heartbeat. I have a set of RF 52s in the bedroom that are capable in their own right. ( They replaced Promedia 2.1s; and are like Promedia 2.1s X10 on the soundstage). Enjoy the fruits of your efforts; and thanks for sharing! Quote Link to comment Share on other sites More sharing options...
Zach N Posted November 17, 2019 Share Posted November 17, 2019 (edited) On 8/2/2011 at 2:05 AM, rongon said: More experiments! Last night, I stopped at Home Depot and bought another few pounds of Duct Seal. Coated the KG4.5 woofer frames, following the method of planet10 from over at DIYaudio.com. [ http://www.diyaudio.com/forums/full-range/111724-extreme-basket-tricks.html ] The result? SUCCESS! The KG4.5 woofers have stamped frames (i.e. cheap). Remove a woofer from the cab, hold it from its magnet and tap on the frame, and you'll hear a distictive "bong" sound, like the sound of a poorly made bell. It sounds like it's in the 500 Hz range and has a decent amount of sustain. Not good. Once again, a coating of Duct Seal removed that problem. Rap on the frame now and all you get is a dull "tink" sound, with just a little hint of ring left. After putting the woofers back in, I hear a marked reduction in upper mid sibilance. Why would damping the resonance of the woofer frame improve the subjective performance of the tweeter? Ya got me... But I'll take it! The upper bass/lower midrange now sounds more full, maybe a little warmer. That same region also sounds more clear, less muddled. This is the biggest improvement so far. Now that I've damped both the woofer frame and the tweeter's plastic horn, there is a big difference in how the upper notes on a piano and orchestral bells sound. Before the Duct Seal treatment on the tweeter, bells sounded very ring-y and startlingly lifelike, even exaggerated. After the damping, they sound more "accurate," or more like I've heard from good cone 'n dome speakers (i.e. not as loud). I'll guess that the undamped tweeter horn rings a bit, which adds some extra zing to the 5 to 10kHz region, and that this has been toned down by damping the horn. While I am very happy with the reduction in perceived sibilance on vocals and the greater accuracy of reproduction of jazz ride cymbal, I kind of miss how orchestral bells used to "pop" to the front of the mix. I listen to lots of jazz, so any obnoxiousness in reproduction of jazz ride cymbals cannot be tolerated. I might get around to removing some of the Duct Seal from the tweeter horns, just to see if I can find a pleasant compromise between "zing" and "accuracy." We shall see... I've read a few threads with pictures of the RF-7 and some other Klipsch crossovers. I see they all use film capacitors. While they don't use anything exotic, the stock caps look like decent-quality metallized mylar. Nothing wrong with that. My experience with cap replacements has been that you'll only get a huge difference when changing capacitor types, such as when replacing non-polarized electrolytics (usually wretched sounding) with good quality film caps. Going from decent mylar film to top-shelf polypropylene usually yields more subtle results. Usually you'll get a little better clarity, a little smoother highs, maybe a little less "grain" in the sound. More of a tweak than a make-or-break change. This Duct Seal experiment has been more than that. It has made me want to keep these speakers. They now sound quite acceptable. I could not enjoy the KG4.5's in their stock state -- too much harsh sibilance and confused lower mids -- but now they're a nice pair of budget speakers that are more efficient than anything else I could get in their price range. Now to the RF-3's. Their problem is a completely unacceptable level of harshness in the upper mids to lower trebles. If I can tame that, then they'll be even better than the KG4.5's (the RF-3's are more efficient and have tighter mids and bass response). First, though, I need to figure out how to get the drivers out of the box, without damaging anything. Wish me luck... -=|=- PS -- I listened to "Solar" from Bill Evans Trio "Sunday at the Village Vanguard" (Analogue Productions SACD). Paul Motian's drums nearly leap out of the speaker. Amazing. The drumset sounds big as life, with just a weenie little 6 watt per channel amp driving. This is great sound for only $250 in speakers. [] Long shot here. Old thread. When you damped the tweeter, did it sound kind of flat? Edited November 17, 2019 by Zach N Quote Link to comment Share on other sites More sharing options...
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