Shock-Late Posted August 28, 2004 Share Posted August 28, 2004 When i installed my Beyma CP25 tweeters (supposed to be 104dB) in place of my K77M, the treble was better but also way too loud. You might be experimenting the same problem with the JBLs, more than a "metal vs phenolic" problem. Numbers aren't everything and I doubt that the K77 is a real 104dB tweeter. I had to lower the tweeter tap on the autotransformer in order to get a balanced sound. I'ev got the stock AA networks, wonder if it's possible to change the tweeter setting on the AlK network... Quote Link to comment Share on other sites More sharing options...
3dzapper Posted August 28, 2004 Share Posted August 28, 2004 Dean, I see and hear no need for any changes to the ALK networks with the JBL's. One Db is barely audible under perfect conditions and, in my room especially with wall to wall carpet and furniture, welcome. The balance is perfect to my old ears just cleaner than and more extended than the K-77 Alnicos. You should try a pair with your AK-4s and let us know the results. The JBL 2404H's would add about $800 to $1000 to the retail price of Khorns and require reworking the top half so I would not expect Klipsch to make that kind of change at this late date. Rick Quote Link to comment Share on other sites More sharing options...
Deang Posted August 29, 2004 Share Posted August 29, 2004 ...but I like the sound of the K-77 in my itty-bitty room. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted August 29, 2004 Share Posted August 29, 2004 "Take a walk on the wild side!" Rick Quote Link to comment Share on other sites More sharing options...
D-MAN Posted August 31, 2004 Author Share Posted August 31, 2004 Okay, I mounted them CORRECTLY (slot vertical) and raised them less than 3" above the previous position(s). The sound is definately different than before. Not as strident, for sure, so running wide open is a definate option now... but it is not as drastic of an improvement to overall sound as the "other way" (before I changed it) especially image-wise. I don't know if it is the different back-lobing pattern or the raised position (combination thereof, most likely) that alters the sound the most... I haven't had time to really musically investigate the changes as far as setup, so I really cannot say what is what yet. DM Quote Link to comment Share on other sites More sharing options...
D-MAN Posted September 7, 2004 Author Share Posted September 7, 2004 Well, kids, you're not going to believe this, but I went back to the "wrong" mount, that is, the slot is horizontal. Also, the polarity on the terminals is reversed when in this position (as described in the literature as having a forward diaphragm movement which I presume is normal)...this is reversed from the other drivers. Weird, but the polarity was reversed as described above when mounted slot-vertical. I found that to be disconcerting, but I double and triple-tested it to make sure. So I'm sure, but also a bit confused by it. It is night and day imaging-wise. How come nobody else has had the same results? Strange... I am running mine unbaffled (more or less) - I suppose that makes a difference. I suspect the back-lobing is very much reduced when mounted slot horizontally. Anyway, thought I'd mention it, in case somebody else runs into this. Other than that, it's been alot of work as the dispersion pattern in the listening room have changed. But I'm getting a handle on it... DM Quote Link to comment Share on other sites More sharing options...
sunnysal Posted September 7, 2004 Share Posted September 7, 2004 not sure I understood...you are running them in inversed polarity to the other drivers? and the imaging is better? Vertical and horizontal I can understnad might have sutle differences in dispersion, etc. but I would think that inverting polarity in either direction would reek havoc with imaging in eihter case...at least this has been my experience when goofing around with polarity on my drivers. let me know, tony Quote Link to comment Share on other sites More sharing options...
D-MAN Posted September 7, 2004 Author Share Posted September 7, 2004 Yep, it's strange, all right. Mounted "sideways" the polarity is reversed from the mid/woof drivers. Mounted vertically, I had to switch the polarity to "match" the mid/woof. The JBL literature says that + to black terminal produces a forward cone motion. This is seemingly correct when mounted "sideways". When mounted slot-vertical (as with John Warrens pic) which I presume is the "normal" method, I had to switch the polarity in order to get any performance - this is bizarre if you ask me. It is quite strange, and I presume that nobody else has run into this? DM Quote Link to comment Share on other sites More sharing options...
sunnysal Posted September 7, 2004 Share Posted September 7, 2004 yup sounds wierd to me, hopefully john, gil or q-man can give some opinions since I makes no sense to me that rotating 90 degrees would require swapping polarity, I would have thought dispersion yes, phase/polarity no...hmmm...tony Quote Link to comment Share on other sites More sharing options...
D-MAN Posted September 7, 2004 Author Share Posted September 7, 2004 Exactly my thought, too. DM Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted September 7, 2004 Share Posted September 7, 2004 Hey D-MAN Just a thought. If your listening of axis of the tweeter then it looks to me like the path length would be different depending on which orientation your using because of the sound wave having to travel past the cheeks of the horn in one orientation and not when in the other orientation and maybe this could cause some interference with the Squawker around the crossover freq. and some lobing in the dispersion pattern of the speaker system that your hearing and noticing in the imaging.Again just a thought? If you are listening on axis of the tweeter then the path length wouldn't change due to horn orientation. As you mentioned maybe its just a matter of the way the horn is dispersing the sound to the room that your picking up on? I know I played with the polarity of the T-35 in my Khorns on the ALK network and I can't say I could really hear a difference if I swaped the polarity but If I used the ETF computer test program then I could make the responce look better around the crossover frequency by using different polaritys for on axis listening versus off axis listening. How are your tweeters setup compared to the squawker? Are they verically aligned with it or are they off to the side of it? When you change orientation of the tweeter are you keeping the path length to the listening position identical? If you are doing this then it seems to me the difference would be more in the way the tweeter disperses the sound in the different orientations. mike Quote Link to comment Share on other sites More sharing options...
D-MAN Posted September 7, 2004 Author Share Posted September 7, 2004 Hey Mike, I think that you're onto something... I am off-axis. The tweets are mounted on the side of the mid-horn (on the outside wall side). They are on the same vertical plane as the mid, but they are axially forward due to the horizontal cant of the mid/tweet assembly (see my UGLY horn thread for a pic sans-JBL's but the same arrangement). I will have to play around some more, but I was - and still am - confused about the apparent phase reversal, as it just doesn't seem to make sense. But the fact is inarguable! I have been over it more than once, and either I have the room-from-hell (something that I have thought for along time now) or there is something strange about the JBL's... DM Quote Link to comment Share on other sites More sharing options...
dubai2000 Posted September 7, 2004 Share Posted September 7, 2004 Yep, that polarity thing is confusing. First I had connected the tweeters like it's described in the JBL literature (i.e. black to +) but giving the red/+ option a try gave better results. Perhaps I better check again.....getting confused here . Wolfram Quote Link to comment Share on other sites More sharing options...
ZAKO Posted September 7, 2004 Share Posted September 7, 2004 Black is + & produces forward motion of voicecoil/diaphram no matter what rotation of baby cheeks. But moving tweeter forward or back will effect phase & time alignment. Perhaps a steeper xover on your system should be used 24db or 48db. I found 18db starts to eliminate any problems. But 24db being even better. remember the 2404 has a wider dispersion pattern and the wall will give you a out of phase reflection. you might be hearing that. you might want to break up that reflection. I dont mean absorbtion . That is not where you want to start the dead zone . you still want to keep that side live. keep dead zones further back away from corner. Or maybe ceiling and floor. Think of the tweeter eminating a large baloon into the room . what part do you want to control. (HF dispersion) Quote Link to comment Share on other sites More sharing options...
dubai2000 Posted September 8, 2004 Share Posted September 8, 2004 Okay, I connected the tweeters now black/+ and there is no question that it sounds different (less 'bright'/open etc - in comparison almost....dull). So that is definitely the way to connect them using Al's original crossovers? I always thought out of phase sound would be like that? Is my hearing at fault? Wolfram Quote Link to comment Share on other sites More sharing options...
D-MAN Posted September 8, 2004 Author Share Posted September 8, 2004 Wolfram, that is my impression, too - Dull and lifeless. I'm sure that that is NOT how they are supposed to sound... If that is it, I could have saved $200.00 each and got APT-50's instead which do not sound dull and lifeless and cost $35.00 each! Maron is right, but I am not changing the location of the driver/horn combination, only turning it on its side at the same location... When sideways and wired + to black, it sounds great! When upright and wired + to black, it sounds BAD... So I've been pondering about this, and it HAS to be the room/location combination. Just a guess... DM Quote Link to comment Share on other sites More sharing options...
D-MAN Posted September 8, 2004 Author Share Posted September 8, 2004 Here's a pic of my situation... DM Quote Link to comment Share on other sites More sharing options...
dubai2000 Posted September 8, 2004 Share Posted September 8, 2004 Well, placing them vertically/horizontally does not change their basic sound in my setup (sorry, but I don't know how to place pics here). I get this 'dullness' once I connect black/plus. Weird! Wolfram Quote Link to comment Share on other sites More sharing options...
sfogg Posted September 8, 2004 Share Posted September 8, 2004 Wolfram, ". So that is definitely the way to connect them using Al's original crossovers? I always thought out of phase sound would be like that?" Guys... don't confuse electrical phase with acoustical phase... they aren't the same thing. In many speaker systems drivers may be wired electrically out of phase with each other but end up being acoustically in phase due to phase inversions through a crossover or whatever. Also at the freqs. these JBLs are running at the wavelengths are pretty small so reflections (or different distances from the tweeter to the mid-range) could easily be causing the differences being noticed. IOW, don't sweat which way you have it wired electrically... go with whichever sounds better to you. If you wanted to try playing pink noise with one tweeter wired one way and the other the opposite. Then just use your balance control to go back and forth between the two speakers to see if you can hear which way blends in better with the mid-range. Shawn Quote Link to comment Share on other sites More sharing options...
Q-Man Posted September 8, 2004 Share Posted September 8, 2004 That's right. You can print the specs. from the JBL web site. You connect the red binding post on the 2404-H driver to the black or neg. terminal on the network. I don't know why rotating the tweeter would make any difference. I run my 290-16K midrange drivers out of phase, or should I say with reversed polarity, because I have better out put at the lower frequencies with them that way. I guess you should wire the tweeters for the way they sound best. I still don't have time to write much. I did get my new computer, but now I don't have any power do to the hurricane. I'm not at home right now. I'm heading back that way now to fire up the chain saw. Other then down trees I made out OK. I was lucky. Quote Link to comment Share on other sites More sharing options...
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