Andre_Db66 Posted February 27 Author Report Share Posted February 27 Simple tone generator? 30hz? What do you suggest as frequency? I was testing untill now with planet dada/Yello. My woofer almost exploded on one side... 😁 Quote Link to comment Share on other sites More sharing options...
Aadams Posted February 27 Report Share Posted February 27 21 minutes ago, Andre_Db66 said: Simple tone generator? 30hz? What do you suggest as frequency? I was testing untill now with planet dada/Yello. My woofer almost exploded on one side... 😁 Set aside the signal generator. You might need a smoke generator but you can start with a simple woofer push test comparison between the two cabs. With all the hivis you have been installing I would not be surprised if you have a leak(s). Are you sealing with gasket tape? You could have gaps around the screw holes for example. Check around the mids as well for a good seal. Did you forget to seal the woofer? Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 The hivis are not in them anymore. Using the tone generator i can hear minimal leakage around 1 tweeter. There is some restistance pushing the woofer in. So to be frank i dont think it is mechanical. In which way does the crossover influence the excursion or lowest frequencies restrictions? I do notice smth else strange on this particular cabinet. When i have the tone gen on the good cab only gives bass but the bad cab gives a buzz in the mids also. This could indicate smthn amiss in the xo? Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 Can an autoformer be faulty? Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 With original tweeters so no gaps around the faceplates of the tweeters. Everywhere there has been a gasket applied and i sense no air movement. Depending on the volume of the amp and the material played, with extreme basses and kick drums, one seems to hold back and i dare to play very loud, the other seems to be getting much more energy to the woofer. It doesnt feel like it is the acoustic suspension playing a part. I know it sounds weird, but this odd sound coming through the mids with the tone gen really worries me... Quote Link to comment Share on other sites More sharing options...
Aadams Posted February 27 Report Share Posted February 27 How old are the fuses? Have you installed new fuses? Also you could swap the signal wire left and right channel to see if the problem stays in the same cab. A reminder: the push test is to assess the recovery speed of the woofer cone after it is pushed in slowly. The recovery should be sluggish not rapid. I don't have an informed opinion on the autoformer, except to say I can't recall anyone ever mentioning a faulty autoformer in their LSTs or 10pis but dirt in the switch has been an issue. Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 The switch works as it performs its task and doesnt crackle or anything. Fuses are original ones and i have no idea if they are as old as the cabinets. Though i fail to see what impact this could have anyway... The push test gives approximate results for both cabinets/woofers, no noticeable difference and slow recovery. Although i have seen slower in my refoamed ar6s, still left and right cab perform the same. I have all the original spragues in there and must say that using a peaktech LCR45 it gives different results on either cab. This is why i am suspecting an electrical fault somehow. As though the signal is not filtered before the woofer. Or xtra energy is routed to the woofer... idk Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 Checking the schematic and position of the switch, the woofer is hooked up without passing through the autoformer. #3 position (correct me if im wrong) It does however go through c1 which i believe to be 1000uF and a coil. This is #10 afaik. So recap... original electrolyte but no idea about the choke. Measured these and they appear to differ from 1 cab to other. 1000uF caps are not expensive so if it has anything to do with this issue could be renewed. I hate to do waste the money if it isnt necessary tho... Quote Link to comment Share on other sites More sharing options...
Aadams Posted February 27 Report Share Posted February 27 31 minutes ago, Andre_Db66 said: Fuses are original ones and i have no idea if they are as old as the cabinets. Though i fail to see what impact this could have anyway... LST fuse condition is a big deal. The fuses degrade over time and can cause quirky behavior. You could temporarily bypass the fuses and gently test the system. The only things to cause large excursions of these woofers is a strong low frequency source signal or an air leak. The passive crossover won't amplify a signal. I would avoid 30 hz on these woofers and play music. It will be safer for the woofer. Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 Making my source signal mono at the pre amp, playing planet dada with very loud volume, 1 woofer tends to bottom out and one woofer is in control. It seems this is how it should be as i read lst2 can play very loud. The woofer of the other however seems to obtain much more energy from the same signal and is dangerously close to damaging. My initial thought would also go out to acoustic suspension problems. BUT, how can it be that when i use a tone gen the mids perform a fuzzy sound? This only on the culprit channel cab... the other has a nice near sub tone and is otherwise dead quiet. This is a paradox as it indicates a electrical issue. Perhaps you are right about the fuse. However i still cannot get my head around the amplification in bass behaviour. The woofer moves wildly with dada planet... Quote Link to comment Share on other sites More sharing options...
Aadams Posted February 27 Report Share Posted February 27 Have you swapped the left/right signal wires to see if the abnormal excursion moves to the other cab? The switch on the LST only affects the mids. The sound profiles occur by varying the midrange level in relation to fixed tweeter and woofer output. Your fuzzy midrange could be from a degraded fuse. Quote Link to comment Share on other sites More sharing options...
frankmarsi Posted February 27 Report Share Posted February 27 @Andre_Db66, That's electronic music isn't it? Maybe, that's too much for these guys to handle as they weren't made with that sort of sound in mind. For me it's like older men wearing skinny-jeans and, that's odd to me pushing the envelope of personal age perceptions. Though perhaps acceptable in music, public display is something else. I still have my 1964 Beatle boots and 1968 bell-bottom hip-hugger jeans but, I wouldn't wear them even to wally's. I at one time noticed my woofers traveling a bit more than they should've but, I hadn't noticed the foam was disintegrating in a dimly lite room. I believe the AR 12" woofer has more travel than a AR-2ax's woofer. To me generally, any speaker should handle any sort of music but, there are exceptions. Ported speakers might do better with electronic music than acoustic-suspension speakers. That's not being judgmental, merely following design parameters. The larger AR-LST's controls only affect the highs and lows. PS, a leak could exist under the basket frame which may have been over looked when re-foaming. It's why I use closed-cell foam speaker mounting tape instead of that confounded putty stuff which is simply not pliable as necessary and presents a world of difficulty when it's needed to be replaced. FM 500 Quote Link to comment Share on other sites More sharing options...
Aadams Posted February 27 Report Share Posted February 27 2 minutes ago, frankmarsi said: The larger AR-LST's controls only affect the highs and lows. Yes I had it reversed. Thank you. Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 If one reads carefully my comments on electro ic music by Yello hence Planet dada, it is obvious this is not the issue here, the other speaker could go louder when the faulty one's excursion limit is reached. They play insanely loud, the LST2. When foam edges are gone, the amount of air passing through the edges will quickly destroy the raiming foam all together when playing at these levels. Yes, this amount of leakage is how it appears to be when observing the fautly cab at work however the foam is new and done properly. The little difference in left and right cab presumably CANNOT amount to this kind of excursion behaviour. I would appreciate a comment on the XO questionaire because how is the buzz possible? Or what causes extra throughput of nrg to the bass unit, possibly lower frequencies than desireable? This is more my own conclusion but i cannot substantiate this and seek backup in theories in this matter. Quote Link to comment Share on other sites More sharing options...
Aadams Posted February 27 Report Share Posted February 27 16 minutes ago, Andre_Db66 said: Or what causes extra throughput of nrg to the bass unit, The crossover is not putting extra energy into the woofer. You are not using a turntable for this, correct? . The overall diminished output of one speaker cab could be a fuse. The buzzing could also be fuse related. Did the excursion move when you swapped the signal cables? If so it could be the source material, or something upstream from the speaker and unrelated to the overall output problem. Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 No turntable, so no subsonic issues. There is no talk of diminished output in one. That one is well balanced as i mentioned, if i use balance control it sounds wonderful and can go the extra mile in volume without excursion problems and the sound is very loud and well balanced. At that point the other is almost blowing the woofer to smithereens. The high and mids stay clean. It is only that 1 woofer behaving so... Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 Tomorrow i shall bypass the fuse and exchange the signal left/right. But this is the second amp/pre combo i tried. First was philips pre on krell power Next accuphase c222 on sansui 919 power. First suspect cab, no leaks substantial enough to allow for this extreme behaviour Second suspect woofer, exchanged them and same. Third suspect xo or fuse... Quote Link to comment Share on other sites More sharing options...
Aadams Posted February 27 Report Share Posted February 27 This is what I think you are saying; When playing in mono the sound of both speakers is centered and balanced. The only problem is the scary woofer excursion. It sounds like source material, especially if the problem moves. If it is the source material, I agree with @frankmarsi lst2 are not the speakers for that music. Probably your JBLs or SRTs or your LSTs that I think I saw in a photo. Tomorrow. Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 17 minutes ago, Aadams said: This is what I think you are saying; When playing in mono the sound of both speakers is centered and balanced. The only problem is the scary woofer excursion. It sounds like source material, especially if the problem moves. If it is the source material, I agree with @frankmarsi lst2 are not the speakers for that music. Probably your JBLs or SRTs or your LSTs that I think I saw in a photo. Tomorrow. Please explain with your reasoning how come 1 speaker can perform this type of material wonderfully tight and much louder than the other. The excursion is not only scary but on the brink of destruction. This is clearly not the notes played but a techical issue... i will deduct and eventually get to the bottom of this. Someone said in another thread of the srt monstrously loud, that is indeed a fact with this sansui power amp. Painful for the ears. I am not even close to these decibels with the lst2. It is the discrepancy between the speakers which i am discussing. Believe me, the lst2 can perform electronic music or any type for that matter perfectly well, but that is not the issue here... Quote Link to comment Share on other sites More sharing options...
RoyC Posted February 27 Report Share Posted February 27 2 hours ago, Aadams said: LST fuse condition is a big deal. The fuses degrade over time and can cause quirky behavior. You could temporarily bypass the fuses and gently test the system. I strongly agree with Aadams. Andre, You are over-thinking the possible issue at the moment. After verifying the problem is confined to the cabinet (which you have done), the very first thing to do is to simply place a jumper across the fuse. It will take you just a few minutes to do this. When the LST/LST-2 fuse becomes worn out it can pass a weak signal causing exactly what you describe. I have run across this several times. The issue is unique to these models. Roy Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 5 minutes ago, RoyC said: I strongly agree with Aadams. Andre, You are over-thinking the possible issue at the moment. After verifying the problem is confined to the cabinet (which you have done), the very first thing to do is to simply place a jumper across the fuse. It will take you just a few minutes to do this. When the LST/LST-2 fuse becomes worn out it can pass a weak signal causing exactly what you describe. I have run across this several times. The issue is unique to these models. Roy Thank you.... So not my choice of program material or excessive leakage of the acoustic suspension. I sincerely hope you are right about it. I had them on craigslist but took them off CL after i let them play on my newly acquired krell power amp. (Loved the detailed sound on low volume) I had little time playing them as i was occupied with many other speakers. I recently bought 2 sets of advent 1 and refoamed a set of alnico ar6. Today was the first moment i could play and turn up the volume with the lst2. I had done so before on a yamaha pc2602 and noticed smthn. However untill today no time to adress the issue... tomorrow i will hopefully resolve it. Cheers everyone... Andre Quote Link to comment Share on other sites More sharing options...
Aadams Posted February 27 Report Share Posted February 27 43 minutes ago, Andre_Db66 said: 1 speaker can perform this type of material wonderfully tight and much louder than the other. This is what I thought you were saying from the beginning until you said they both played loud. Ok so they are NOT balanced and centered in mono. The woofer excursion problem and the loudness balance problem could 2 different issues but hopefully they will both vanish when you check the fuses. Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 27 Author Report Share Posted February 27 Highs balanced Mids balanced Lows troublesome on 1 cabinet. Balanced until one cone tends to drop out of the frame due to excessive excursion. Fuseholders - I found blank shiny contacts on the good speaker. The problematic one has dull not shiny corroded like contacts. Both fuses seem new to me. Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 28 Author Report Share Posted February 28 Heavily corroded fuse holders. Previous owner of my LST had shorted the fuse holder on 1 speaker and gave me the holders along with the sale. I realised these were in much better shape than above pair and this morning i replaced it in the faulty LST2. It seems planet dada is now playing good on both speakers and yes i fully agree that it is quite xtreme to play this kind of material on these beauties but given the renewed foam and excellent tonal balance it performs very well. For sake of the thread topic, i have to add that when the first cabinet was done with hivi tweets, the second was done with the current tweeters. A threesome of 8R AR. I did some hours of comparative listening and could not define a difference in left and right sonic display. Excellent tweeter and the 4,7uF with .05mH coil work top notch. Unfortunately i have now 6 new hivi tweeters in the cupboard. If anyone needs a set or perhaps all, i can make a very nice price. They were 30 a piece, but willing to go under a fair amount. 80 for all, obviously plus shipping. I have 6 Jantzen 0,05mH coils along the hivi btw... Also 3 2ax mids and 1 2ax woofer(needs recone) and 2 3a tweeters missing the voice coil. If anyone is interested let me know plz... Quote Link to comment Share on other sites More sharing options...
Andre_Db66 Posted February 28 Author Report Share Posted February 28 PS the buzz in the mids was replicated on the other speaker after changing signal wires at the power amp. Quote Link to comment Share on other sites More sharing options...
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