waikikidc Posted January 22, 2003 Share Posted January 22, 2003 i have a pair of old hereseys and also an old pair of cornwalls that both make a very loud popping sound that sounds like it is coming from the mid range section,especially during bassier parts of a tune if i play the same amp thru a pair of old jbl s they sound fine so i dont think it is the amp. anyone have any ideas? thanx i appreciate any help dc Quote Link to comment Share on other sites More sharing options...
michael hurd Posted January 22, 2003 Share Posted January 22, 2003 Could be a poor connection on the crossovers ? Or the wiring to the midrange drivers ? However this seems unlikely that this would occur on both pair of loudspeakers. I wonder if the capacitors used in the crossovers decided to take a dump, however this is pretty unlikely as well. How old are the speakers ? At what volume levels does this occur ? Quote Link to comment Share on other sites More sharing options...
JohnA Posted January 23, 2003 Share Posted January 23, 2003 I think its a crossover issue. The Cornwall and Heresy crossovers are 1st order and will let some bass into the squawker, but not that much. If your caps have gone bad, the squawkers may have no protection at all and will clack as the diaphragm hits the phase plug. Find a good proaudio tech and have everything tested. Quote Link to comment Share on other sites More sharing options...
lynnm Posted January 23, 2003 Share Posted January 23, 2003 I have difficulty buying the Xovers on this one given that we are looking at 2 pairs of speakers. I would be looking a little sideways at the amp or something else upstream of the speakers. The fact that the amp sounds OK through the JBL's argues against my viewpoint but I would still try them on a different amp. Have you tried to ascertain whether it is actually all four speakers making that sound ? I would think that if any one or two were to make that noise at high volume it could sound as if it were coming from all of them. Quote Link to comment Share on other sites More sharing options...
waikikidc Posted January 23, 2003 Author Share Posted January 23, 2003 thank you all for your input the speakers (all four) are about 20 years old maybe older all four make the noise the noise is identical from both pairs of speakers i would call it more of a crack sound but you could call it popping i have also tryed an soild state kenwood amp too and it also makes the noise the noise is only at high volume the amp usually used is an old macintosh i am in nyc area anyone know of a knowlegeable tech nearby please let me know i have tryed asking a few techs and most(you can tell sometimes)dont have a clue what they are doing.so i dont want someone like that again thanx for all your help dc Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted January 23, 2003 Share Posted January 23, 2003 It sounds to me like you are running the amplifier(s) into clipping and causing the bass drivers to bottom out, not the midranges. I would bet that the music being played at high volumes was heavy in bass content as well, causing the woofers to bottom or snap when the amplifier is run into clipping. I cannot see all four speakers having the same problem. The problem lies with either your equipment, volume level, tone controls being set other than flat, perhaps the loudness contour "on", and the amp being driven into clipping. It is highly unlikely that all the Klipsch speakers are suffering from the same problem. Quote Link to comment Share on other sites More sharing options...
waikikidc Posted January 25, 2003 Author Share Posted January 25, 2003 hi again all tones are set flat, bass and treble at high noon.also they make the same cracking noise with two different amps.this has been going on for a while ,i just found this forum to ask the question ,which is why i am asking. believe it or not i prefer the sound of properly sounding klipschs to anything .i am a pro musician and use nothing but jbl s in that . so if anyone knows of someone in the nyc area that might be able to get at least one pair of klipschs working right it would make me happy the caps in the crossover idea sounds interesting i wonder if anyone else thinks that sounds like it might be that. thanx again alll dc Quote Link to comment Share on other sites More sharing options...
WMcD Posted January 25, 2003 Share Posted January 25, 2003 I'm very interested. I get a similar sound playing Tyransaurus Lunch on a Telarc CD (infra sound) on home made K-Horns using a vintage Sony amp. Probably around 30 watts. I'm very careful with that track because the EVM 15L stopped working. At the time, I thought maybe the infrasonics did something horrible to the amp and it went nutzo. I also used a test CD, "Sound Check II" on the Forte II's last year. The 32 Hz bandpass noise created that clicking and I turned down the level. This was with a newer Sony mini system amp. I didn't have time to investigate. Tomorrow I'll take the grill off the Forte II's and see what the bass driver is doing. I suspect it is being driven to its limits. I'm really cautious in view of the loss of the EV unit. But tell us about your experience leading up to the problem. I don't see mention that the system had been set up for a long time and that this just developed out of the blue. Also, is it limited to that one CD? Let me suggest you try turning down the bass control. That might identify whether it is the bass drivers being driven to limits. My guess is that it is difficult to remove the grill from the Heritage line to watch the bass drivers. I'll let you know what I find. Gil Quote Link to comment Share on other sites More sharing options...
lynnm Posted January 25, 2003 Share Posted January 25, 2003 William Gill I too am puzzled. If this were happening with only a single amp I would wonder if perhaps infra sonics in the 10hz. (+/-) range were being generated under the music and therefore creating a situation where the woofers' neutral or "at rest" position was effectively lowered by this subsonic activity. Nonetheless this condition apparently is occuring with two different amps and other speakers are not exhibiting this behaviour with either amp. Damn !! I wish I were near enough to be able to tackle this one hands on. Truth be known it is just this kind of issue that makes me love being a tech ! There is an answer and by God I would track it to the ends of the earth to find it !! Quote Link to comment Share on other sites More sharing options...
djk Posted January 27, 2003 Share Posted January 27, 2003 Old JBLs are usually 8 ohms. Cornwalls usually are 4 ohms. The Heresy after 1985 is 4 ohms. I expect the foldback current limiting in the amplifier is being engaged. This will make a loud 'popping' sound come out of the midrange driver. I've heard the Cornwall handle in excess of 1KW on clean program material with no signs of stress. I think it is the amplifier. Quote Link to comment Share on other sites More sharing options...
WMcD Posted January 27, 2003 Share Posted January 27, 2003 Well, this just shows what I know. Not much. I took the grill off one of the Forte II and ran that test track again. Yeah there was some diaphragm motion, but no clacking. I ran the volume up to full and still nothing. Then put in the loudness. Still no clacking. Some things in the room were vibrating pretty well. However, the speakers and system were well behaved. The only anomaly was that there was some static-like sound when I adjusted the volume control. (It is digital, so it is not a dirty pot.) So, perhaps in my first test I went for the volume control as the bass tones became louder, there was the static, and I interpreted that as noise from the bass. Of course I'd be sensitized to it by my earlier experience. Gil Quote Link to comment Share on other sites More sharing options...
SkidmoreJ Posted May 6, 2003 Share Posted May 6, 2003 If you can get the crossovers to South Jersey, I can test the components or rebuild the crossovers. I have the equipment to test the components. What music (artist, song) is playing at the time of the popping? Jim Quote Link to comment Share on other sites More sharing options...
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