Dylanl Posted September 21, 2004 Share Posted September 21, 2004 I have a set of 1974 khorns and I'm noticing that I have a 2db loss in bass coming out of the bass bin on my left speaker. I tested both speakers with an SPL meter through the same passage of music. Is this normal or could something be wrong? I checked all my connections inside and outside the cabinet and the only difference I could find is one speaker is against 2 cement block walls and the other has only one wall that is cement block and the other is studs and drywall. I'd appreciate any help. I'm baffled. Quote Link to comment Share on other sites More sharing options...
Deang Posted September 21, 2004 Share Posted September 21, 2004 "I'm baffled." Nice play on words. I don't think it's all that unusual to get that kind of difference between speakers when you factor in placement issues -- and in your case, a good difference in material behind the Klipschorns. So, should I guess that one with cement blocks all the way around has higher bass output than the one with one section backed up against drywall? Not surprising, as you are undoubtably getting some loss through the drywall section. Quote Link to comment Share on other sites More sharing options...
Dylanl Posted September 21, 2004 Author Share Posted September 21, 2004 Just did another test move speaker a to the b position and speaker a is still down by 2 db to 3 db. I also switched the leads comming out of the amp with the same result. So, it can not be placement it has to be the speaker. What could cause this? Are there any tests I could preform on the woofers to see if they are both O.K.? Quote Link to comment Share on other sites More sharing options...
lynnm Posted September 21, 2004 Share Posted September 21, 2004 Two additional thoughts: I.) Are you sure that your amp actually puts out equal power to each channel. II.) If your amp has a monaural setting try measuring while playing a mono record with the amp set to Mono. Quote Link to comment Share on other sites More sharing options...
Dylanl Posted September 21, 2004 Author Share Posted September 21, 2004 I am going to try my SS amp to see if the results are the similar. I have a bad feeling they will show the same. What causes this? If the specs. are the same and construction is the same the results should be very close right? Unless there is a flaw somewhere. Quote Link to comment Share on other sites More sharing options...
BEC Posted September 21, 2004 Share Posted September 21, 2004 I think you should try loosening and retightening all the screws on the terminal strip on the crossovers. That corrected an imbalance on a pair of my Lascalas that was more severe than yours. Bob Crites Quote Link to comment Share on other sites More sharing options...
TBrennan Posted September 21, 2004 Share Posted September 21, 2004 I wouldn't be surprised that this was simply the normal variation between speakers. These are mechanical devices. Quote Link to comment Share on other sites More sharing options...
Deang Posted September 21, 2004 Share Posted September 21, 2004 The Cornwalls I had in here at one were like that - tried everything - and finally gave up - and resorted to using the ever cursed balance control. You can start by tightening the screws and see if it makes a difference. If it does, mind as well remove the wiring from the terminal stips and clean them with denatured alcohol. Quote Link to comment Share on other sites More sharing options...
Pistol Pete Posted September 22, 2004 Share Posted September 22, 2004 If your pretty sure its a solid 2 db then id start by cleaning the driver and speaker wiring connections. 2dB is quite abit for a single driver to be off if you ask me. What SPL level are you testing at and does it vary? For example how db is it off at 80dB vs 95dB ? Quote Link to comment Share on other sites More sharing options...
v3spitfire Posted September 22, 2004 Share Posted September 22, 2004 After cleaning with denatured alcohol, try drinking distilled alcohol. See if that corrects the imbalance....Sorry....You can go back to trying to solve the problem, I'll go to work. Quote Link to comment Share on other sites More sharing options...
ricktate Posted September 22, 2004 Share Posted September 22, 2004 Im redoing some Ks right now and found in a little test i made that the so called airtight chamber behind the woofer is in no way airtight,,,so after using alot of silicone and a few more tests i got one much more tight than it was. So one of yours may have a big leak in it and the other one a little leak .in the ones im redoing all the joints seemed solid, glue looked good but air went out as fast as i put it in,,,just a thought,,,it easy test to do,,,Rick Quote Link to comment Share on other sites More sharing options...
Dylanl Posted September 22, 2004 Author Share Posted September 22, 2004 I tested at 110db and 100db on the SPL meter. It does not make a difference whatever the SPL level 1 speaker reading is always higher the other is 2-3 db lower. I disconnected all drivers but the base bin. I placed the meter at exactly the same place on both speakers (right at the throat). Could this be my crossovers? The reason I even tried this is by ear you can hear a large difference. Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted September 22, 2004 Share Posted September 22, 2004 It could even be that one of your mids is on a different set of taps on the T2A Autoformer on the AA network. It sounds like you are measuring the midhorn output primarily and not the entire speaker as a whole? I would check the woofer and the woofer connections in the bass bin as well. Check for a good seal of the bass bin, the weatherstripping is most likely deteriorated. Another thought is to swap out the K-55V driver itself over to the other speaker and see if the 2-3db drop follows the mid driver, if it does not the crossover could be at fault somewhere. First check to see if the midranges are connected to the identical taps on the T2A. See if any of the above helps. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted September 22, 2004 Share Posted September 22, 2004 Sounds like its an acoustical problem, rather than an electrical one - but who knows? I have a couple of questions: Are the Khorns matching in age? i.e., are the K33 drivers the same vintage? are they old? Assuming that the drivers are virtually matched, the only other thing to do is check the cabinet in question for air leaks in the back-chamber. This would definitely lower the bass response. DM Quote Link to comment Share on other sites More sharing options...
Dylanl Posted September 22, 2004 Author Share Posted September 22, 2004 Frzninvt, D-man - I am testing the bass bin alone. Pulled the drivers and switched from 1 cabinet to the other. The speaker that was down -2db went to +2db and the other went from +2db to - 2db. I think this is pointing driver alone. Quote Link to comment Share on other sites More sharing options...
DrWho Posted September 22, 2004 Share Posted September 22, 2004 Well it sounds like you've got a crossover problem: You already tried swapping location and the problem followed the speaker. This means that acoustics are not the problem. You swapped speaker cables and the problem remained with the speaker. This means it's not your amp or anything else upstream. You swapped drivers and the problem did not follow the driver. Thus, the problem must be between the driver and the crossover. OR, the problem is with the bass bin itself. I'm not familiar enough with the crossover, but would it be easy to run a test after switching the crossovers? If you find that the problem doesn't follow the crossover, then you probably have some kind of leak inside the bass cabinet. If you have test tones, I would suggest trying to get an idea of the difference in frequency response. A bass horn with a leak will have much less lower extension than one without a leak. Knowing the frequency response will let us know if this is the issue. Anyways, being that your speakers are so old, I would hypothesize that a cap in your crossover has probably gone bad. Now that I think about it...you may want to do another frequency response test with the midrange driver plugged in too. It's possible that a bad cap could cause an increase in 2dB, which means the speaker with the flattest response between the two drivers is most likeley the unbroken one. Quote Link to comment Share on other sites More sharing options...
Dylanl Posted September 22, 2004 Author Share Posted September 22, 2004 Sorry if my last description was hard to follow. When I switched drivers (K33) from 1 bin to the other the problem also moved. Funny thing the woofer looks fine. Are ther any tests that could be run on the k33 itself? I also swapped crossovers and the results showed that they were not the problem. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted September 22, 2004 Share Posted September 22, 2004 I would think that its unlikely that the crossover would suck up 2db, but one or more bad, oxidized connection or solder joint, or badly corroded wires could do it, in theory, but it would have to be quite resistive. IMO, one could expect to actually hear that kind of problem, though... More than likely, it's an air leak in the back chamber as previously reported by ricktate, but that's just a guess. DM Quote Link to comment Share on other sites More sharing options...
D-MAN Posted September 22, 2004 Share Posted September 22, 2004 You beat me to the submit button! If the problem moves with the driver, it's the driver, all right. I would get a new pair, so that they are as well-matched as possible in age and performance. $130 ea from Klipsch. DM Quote Link to comment Share on other sites More sharing options...
Dylanl Posted September 22, 2004 Author Share Posted September 22, 2004 On the new drivers are the sonics the same? Does anyone have any thought to how the 2 speakers could be that much different? The tech. at Klipsch told me that 3db between a matched pair of woofers is an industry standard. Is this true? If I purchase a new pair could I end up with the same problem? Quote Link to comment Share on other sites More sharing options...
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