Croc Posted March 1, 2006 Share Posted March 1, 2006 i own about a 30 year old pair of Lascalas with alnico drivers and AA xover. using Guy's recommendation (i guess i'm luky to have Guy at a 30 minutes drive distance[]) i moded the xover to A by removing "unneccessary" parts. the sound changed a lot. my impressions so far: good things: 1. tweeter sounds much better, smoother and more extended 2. transparency in mid and treble improved a lot - now it's quite in the league of my Sonus Faber Cremona - and this is a complement. that "veil" and significant grain that i had in mid and somewhat in treble is gone. very impressive 3. over sound is much smoother and not "shouting" or "raggy" at all negative things: 1. sound lost its size and height. now it doesn't sound at the whole front wall but just between the speakers 2. midbass got much weaker - on spl meter i measure about 8 db drop from ~140 hz. i had to tail my REL Stadium 3 sub a lot and still didn't find a good combination. 3. the sound became smooth....... i'm missng that hot huge and "in your face" midrange......... in short they became smooth and very polite[] i'm wondering why is that and whether "new" A xovers (like Bob's one) provide a similar difference............ Quote Link to comment Share on other sites More sharing options...
D-MAN Posted March 1, 2006 Share Posted March 1, 2006 One things for sure, you changed the frequency distribution between the drivers and that effects the dispersion characteristics in the room. It may even require different room treatments, etc. Next, try adjusting speaker placement, different angles and positions in the room to optimize it as best you can - its all interrelated.. DM Quote Link to comment Share on other sites More sharing options...
BEC Posted March 1, 2006 Share Posted March 1, 2006 Changing from AA to A should have only effected how the tweeter sounds. You should get those old bad caps out of that crossover and replace them to really know how it sounds also. Bob Crites Quote Link to comment Share on other sites More sharing options...
Croc Posted March 1, 2006 Author Share Posted March 1, 2006 Bob, what caps can you recomend for DIYer? Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted March 1, 2006 Share Posted March 1, 2006 My preference is the type A over AA That is very nice to be near Guy. If you think about it, pass along my greetings. Quote Link to comment Share on other sites More sharing options...
BEC Posted March 1, 2006 Share Posted March 1, 2006 Well, I am fond of the GE polypropylene in oil cans, but most any good polypropylene cap would be a big improvement over the worn out original ones. Bob Quote Link to comment Share on other sites More sharing options...
garymd Posted March 1, 2006 Share Posted March 1, 2006 Say hello to Guy for me also! He was the first to tell me the differences between AA's and A's. You need to talk him into another set of Khorns although I know he loves his "Big Reds" and Super Tweeters.[] Quote Link to comment Share on other sites More sharing options...
pmsummer Posted March 1, 2006 Share Posted March 1, 2006 Well, I am fond of the GE polypropylene in oil cans, but most any good polypropylene cap would be a big improvement over the worn out original ones. Bob Bob, Are you sourcing those caps for original Cornwalls? My pair are celebrating their 28th this year, and I want to give them a Birthday present. Quote Link to comment Share on other sites More sharing options...
BEC Posted March 1, 2006 Share Posted March 1, 2006 Yes, type B crossovers, I presume. I could send you a set of caps and mounting brackets for the caps. Bob Crites bobcrites@centurytel.net Quote Link to comment Share on other sites More sharing options...
Croc Posted March 1, 2006 Author Share Posted March 1, 2006 guys, discard my previous impressions - i just went to listen music - put the mingus with heldridge, dolphy and others. at some stage i noticed that the sound stage is too much "dead centered", after a moment "mono like" asociation springed into my mind and a second later i saw that "mono" switch is turned on on my pre [:$]so back to the stereo - the problems are gone [], perhaps a mid bass and the subwoofer integration still need some triming.but transparancy is still there - this is great.and the tweeter became very good. perhaps still not Cremona but very very descent - it makes me wonder are replacements are that good that people throw away the original ones?.............. Quote Link to comment Share on other sites More sharing options...
Deang Posted March 2, 2006 Share Posted March 2, 2006 "Changing from AA to A should have only effected how the tweeter sounds." I think it changes everything. Quote Link to comment Share on other sites More sharing options...
Croc Posted March 2, 2006 Author Share Posted March 2, 2006 "Changing from AA to A should have only effected how the tweeter sounds." I think it changes everything. in my case it definitely did. the electrical explanation might be is that in AA from DC point of view all terminals (i mean imputs, and terminals of drivers - all "pluses" and "minuses") are shortcircuited. so even at AC removal of parts from tweeters branch affects what bass and mid drivers "see" in their branches. another one - can somebody pls provide with an AA xovers electrical scheme? to Bob and other xover gurus, except capacitors what other elements would you recomend to refresh? actually if we put capaciotors out it leaves us with transformer, coil (for bass), wires and barrier strip. Quote Link to comment Share on other sites More sharing options...
BEC Posted March 2, 2006 Share Posted March 2, 2006 Dean said: "I think it changes everything." Dean is wrong, but I can't prove it to him until he starts to believe in test equipment. Bob Croc, Just the caps. I have never found anything else to be bad on an old Type AA crossover out of hundreds I have rebuilt. Actually, one more thing on the Type AA. A lot of times, Klipsch messed up and put a steel screw in the 245 mH inductor. That screw has to be brass or stainless steel or it changes the value of the inductor a lot. You can check the screw with a magnet. If the magnet picks up the screw, you need to replace it. Bob Quote Link to comment Share on other sites More sharing options...
Deang Posted March 2, 2006 Share Posted March 2, 2006 O.K., you have a reduction in voltage in the tweeter section of the AA network compared to the A. We all know it's because of the sharper filter slope on the AA. So, someone asks -- "What's the difference between the two networks?" You look at your voltage measurements, but you respond using a different language: you tell them the tweeter in the Type AA is about 3dB down in comparison to the Type A. We want to know what's happening acoustically, and since this is the case, we don't talk to each other in volts, we talk to each other in dB. It's not just about voltage. When you change the distribution of energy between the drivers it impacts the sound of the whole speaker. Decrease the amount of energy going to one driver and it perceptually lifts it somewhere else. The acoustic response is what matters. When going from the Type AA to the Type A -- what will a person hear? 1) More high frequency energy. Depending on the user's room and listening habits this could be either good or bad. Those involved in intimate type listening sessions at lower volumes will probably prefer the Type A filter. Those who engage in live listening levels will probably appreciate the reduced tweeter output of the Type AA. 2) More mid frequency energy. The first order filter behavior of the Type A takes the tweeter further into the squawker's operating range. There is more overlap. 3) Less perceived bass output. When you have more energy at the top, you hear less at the bottom -- even though nothing at the bottom was "changed". I do have a Real Time Analyzer -- and use it. I'm more interested in what's happening acoustically -- this way of measuring is more suited to my interests. Though I've certainly been burnt by my ears on more than one occasion -- I still prefer them over using my nose. Quote Link to comment Share on other sites More sharing options...
Deang Posted March 2, 2006 Share Posted March 2, 2006 Actually, one more thing on the Type AA. A lot of times, Klipsch messed up and put a steel screw in the 245 mH inductor. How do you know they didn't do it on purpose? Quote Link to comment Share on other sites More sharing options...
BEC Posted March 2, 2006 Share Posted March 2, 2006 Dean said: "How do you know they didn't do it on purpose?" Because then they would have called for a 350 uH inductor on the schematic. Bob Quote Link to comment Share on other sites More sharing options...
Deang Posted March 2, 2006 Share Posted March 2, 2006 [] Quote Link to comment Share on other sites More sharing options...
BEC Posted March 2, 2006 Share Posted March 2, 2006 Perception is one thing, reality is perhaps something different. The change from AA to A only effects the tweeter voltage. The power involved with the tweeter is just too low to effect the other two circuits. Bob Crites Quote Link to comment Share on other sites More sharing options...
Deang Posted March 2, 2006 Share Posted March 2, 2006 Perception is reality. Quote Link to comment Share on other sites More sharing options...
Allan Songer Posted March 2, 2006 Share Posted March 2, 2006 Your perception is your reality. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.