JoeRiff Posted February 23, 2006 Share Posted February 23, 2006 I bought a set of Belle's (vintage 1984) from a local guy a few weeks ago and have set them up at my house. What I'm noticing is the midrange sounds muffled/compressed at lower volume levels. It is particularly noticeable with vocals, esp. with a male singer. Do you guys have any idea what could be causing it? I realize it's hard to know what I'm talking about without hearing it. The problem seems to dissappear once the volume knob goes past about 1/4 of the way on an old-fashioned volume knob. The really strange thing is, they sound better than just about anything I've heard at about 1/3 volume (which is quite loud). The mids and highs really come alive at that level, and the sound quality is exceptional. It's almost like these speakers are Dr. Jeckl and Mr. Hyde depending on were the level is set. Here is some more info about my set-up that may also be influencing the sound: - I have a fairly cheap Sony stereo reciever that is about 7 years old (100wx2) - I have 9 foot ceilings - There is not much "soft" furniture or any curtains in the room, which has plaster walls - The crossovers definitely look like they need to be replaced and are rather corroded. I plan on upgrading to a "real" amp and replacing the crossovers in time, but I would like to adress the most immediate need first. Any ideas on what may be the culpret? Quote Link to comment Share on other sites More sharing options...
Jeff Matthews Posted February 23, 2006 Share Posted February 23, 2006 Crossovers. When mine were re-capped, it was like unloading wax from my ears. They just opened up like I could not have imagined. And I was a cynic as to the crossover idea before that. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted February 23, 2006 Share Posted February 23, 2006 Sorry, I couldn't help my laughing Jeff!!!! Joe, Jeff is right of "coarse". It took the combined karma of the entire forum and a pair of AA xovers with cheap ebay capacitors to get the mountain to move in the proper direction. (Did you mail them yet Jeff?) What crossovers do you have in your '84s? Rick Quote Link to comment Share on other sites More sharing options...
JoeRiff Posted February 23, 2006 Author Share Posted February 23, 2006 What crossovers would you guys reccommend? I've heard mention of ALK and Bob Crites before. Would I be looking at a rebuild or a replacement?(they're in pretty rough shape). What should I expect to pay? Thanks for the help. I have the original crossovers still in the speakers. I'd have to look to see if they have a model # on them. I've also seen some on eBay before. Quote Link to comment Share on other sites More sharing options...
Def Leper Posted February 23, 2006 Share Posted February 23, 2006 I agree with with the crossover suggestion. I had Bob Crites rebuild my '84 Cornwall B-3 crossovers and the lower midrange really tightened up, noticeably at lower volume levels. Quote Link to comment Share on other sites More sharing options...
JoeRiff Posted February 23, 2006 Author Share Posted February 23, 2006 Just out of curiousity, what goes wrong in the crossovers over time? There is quite a bit corrosion on them, but does anything else go bad? Do the caps dry out? Quote Link to comment Share on other sites More sharing options...
Jeff Matthews Posted February 23, 2006 Share Posted February 23, 2006 Rick correctly describes "the force it took to move a mountain." I can be a tough sell, but I'll say this: Thanks to all of you Forum members out there for prodding me along. Rick, I mailed them to Bob on Tuesday. He either received them today, or he will tomorrow. They were mailed Priority Mail. A special thanks goes to you for all your help. Quote Link to comment Share on other sites More sharing options...
Jeff Matthews Posted February 23, 2006 Share Posted February 23, 2006 Just out of curiousity, what goes wrong in the crossovers over time? There is quite a bit corrosion on them, but does anything else go bad? Do the caps dry out? Whatever the physics is, the capacitors become no good. They are replaced. The crossovers themselves should remain good and usable. You send them to your crossover guy of choice; he does what he does; and he sends them back. (I think everyone - e.g. BEC, Dean, Al - works that way). Quote Link to comment Share on other sites More sharing options...
ancientdude Posted February 23, 2006 Share Posted February 23, 2006 Where did you pick up the belles? You didnt happen to be the one who beat me to a pair in the Seattle area, were you?! [] Quote Link to comment Share on other sites More sharing options...
ancientdude Posted February 23, 2006 Share Posted February 23, 2006 Before anything, try getting a pair of new mid-range diaphrams... Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted February 23, 2006 Share Posted February 23, 2006 Do you have another amp you can try? The symptom you are describing can also sometimes be associated with components upstream from the loudspeakers, and in the past was improved by a small value capacitor -- something in the range of 47-100pfd -- that, depending on the type of volume potentiometer, was used as a bypass between the input end of the volume control and it's wiper. This capacitor was used to form a high-pass filter on the volume control to compensate for the potential loss of high frequency information at very low volume rotations. I don't have it in me right now to go into the technical reasons for that, but musical instrument amp techs sometimes 'clean' up that muddiness you describe with the use of such a bypass cap, which can be installed in a way that enables it to be switched in and out of the circuit. This is NOT something I am suggesting you try yourself, unless you have experience working on electronic equipment. It's just a technique that's sometimes used to bring some sparkle and life back into the sound, and I mention it because of what you said about the change in sound once I higher rotation of the volume control is achieved. ....or, as others have said: drifted values in crossover components, maybe. If you have another amp/preamp or receiver you could try, you might try them to see if you notice an improvement. Erik Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted February 23, 2006 Share Posted February 23, 2006 How far is your CD player from the receiver? Better stated, what is the lengh of cable between your CDP and the Sony? Erik Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted February 23, 2006 Share Posted February 23, 2006 Of course it is difficult to diagnose via the internet.... However, if it is truly muffled at lower volumes (I mean very different sounding) then go slow before you spend a lot of money on new crossovers. The theory, with some data also, is that old capacitors provide an increased DC resistance to the drivers. This would be like adding a resistor in series with the circuit - not a good thing. Why this would vary as a function of level is pure speculation (if it is in fact the problem). Given that, go slow before you spend your money on fancy crossovers (although there are other reasons why you may want to eventually do this). IMO statistically it is more likely the electronics that are driving the speakers. Amps can be notorious for "not opening up" until you reach a certain overall level. Perhaps you could swap/borrow another amp and have a listen. The amp does need to be fancy since the speakers are efficient and do not present a terribly low impedance. However, the amp does need to provide a clean signal since Klipsch speakers are ruthless in revealing any hiss, hum, or distortion. In fact your impression may be the result of hearing relatively more distortion at lower levels (a characteristic of some solid state amps) Incidentally, most speakers sound "better" when they are louder. This is an old trick that many stereo salesmen are well aware of. Good Luck, -Tom Quote Link to comment Share on other sites More sharing options...
sunburnwilly Posted February 23, 2006 Share Posted February 23, 2006 When you rope caulk the horns , the caulk goes on the outside . [][] Seriously , I believe you have the AB networks which are some wacky beasts . You will get much better results with rebuilt AA's . On a side note , if they are used in the rear surrounds the AB's work quite well ... Quote Link to comment Share on other sites More sharing options...
JoeRiff Posted February 24, 2006 Author Share Posted February 24, 2006 To answer a few of your questions: I have the the "TYPE AB" crossovers. The waxpaper on the capacitors looks dried out and shrunken. There is also corrosion on some of the connections and the screw terminals. I have access to another receiver that I'm going to try hooking up. If it yields no difference, I'll have to convince my dad into letting me borrow his Crown amp/pre-amp combo. I also thought about the blown diaphram thing, but don't I have the opposite problem? (blown diaphrams sound better at low volume and bad at high volume) Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted February 24, 2006 Share Posted February 24, 2006 Joe: Cleaning up connections would make a good project for you! Corrosion and oxidation on connections is not good, and you might start with those, first. If the speakers were in a humid area and the leads show signs of green oxidation and other gunk, it might be a good idea to consider replacing the leads for the crossovers to the drivers with new wire -- or if not that, than using a deoxidant + lubricant spray (AFTER ALL ASSOCIATED EQUIPMENT IS TURNED OFF) to clean things up. Disconnect the inputs into the networks, as well as the leads from the drivers to the outputs of the crossover. Clean all of that stuff up with a good spray and brush with an old toothbrush, and remove the loosened oxidation with an abrasive green pad (gee, am I afraid to offer name brands for this stuff, or what?) If you don't have any contact cleaner/lubricant, rubbing alcohol makes a good cheap contact cleaner. Clean especially thoroughly on the under sides of screw heads and the spade terminals of the speaker leads. If you are handy and know how to do this (or are willing to learn with a piece of practice wire), you can cut off the leads just beyond the point of corrosion, re-strip the insulation, and use a crimp connector to crimp on a new spade terminal or ring terminal. Radio Shack also sells a box of assorted sizes that will work fine. That possibly failing to improve things (but an inexpensive thing to try first), a crossover upgrade can be considered, and the guys who make them here all do outstanding work. Just PLEASE don't ask the best kind of capacitor to use for the upgrade![:S][] Erik Quote Link to comment Share on other sites More sharing options...
JoeRiff Posted February 25, 2006 Author Share Posted February 25, 2006 My dad came over today to have a listen and give his opinion. He pretty much agreed with what I said earlier. They just sound muffled. We played Paul Simon's "Graceland" album, which sounds phenomenal on my dad's Khorns. That album made the sound problems that much more obvious. My dad also said that the sound seemed similar to "clipping"- as if the amp was clipping. Obviously, though, that doesn't make any sense at about 75-80db sound levels with a 100w amp. The next two things I am going to try are: 1) clean the terminal contacts on the crossover network and 2) try my dad's Crown power line amp and pre amp to see if the sound changes at all. Quote Link to comment Share on other sites More sharing options...
J.4knee Posted February 25, 2006 Share Posted February 25, 2006 At a minumum get Al K's Universal replacements (Very affordable) or even better get a set of ESN's from him but they cost about as much as your Belle Klipsch. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted February 25, 2006 Share Posted February 25, 2006 Joe, I see that your Belles have the type "AB" network. This may be the problem. That is a very strange network. I runs the woofer full range allowing it to roll off naturally. That happens above 700 Hz. The squawker rolls off below about 900 Hz. I can only guess where the acoustic crossover falls. I think it's probably around 800 Hz. The squawker is also reverse-equalized casuing it to drop in level as you go up in frequency. It also runs all the way to 20K depending on the K55 driver to poop out at 6000 Hz. The only good thing about it is that the tweeter filter is similar to my extreme-slope ES5800 network. I would replace the AB with something else. I would suggest my Universal "ALK". It would be a good choice. Al K. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted February 26, 2006 Share Posted February 26, 2006 " The squawker is also reverse-equalized casuing it to drop in level as you go up in frequency." Is this a second-order Butterworth? If I remember right (which I might not!), there is a null in response at the crossover point if the drivers are connected in parallel with each other and the input (+ to +). The reversal on the squawker could then be used to compensate for the resulting dropout, in effect resulting in a peak at the crossover point. Is there a schematic available for this network? Erik Quote Link to comment Share on other sites More sharing options...
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