sfogg Posted February 13, 2009 Share Posted February 13, 2009 Altec's test for diaphragm alignment on a 902 was 500hz tone played back at high volume to measure distortion and listen for buzzing. Shawn Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 13, 2009 Share Posted February 13, 2009 "I remember reading Shawn's comments to Al, saying he crossed them at500 1st order, played loudly with no problem, and Al replying that that might damage the drivers, and at the least, would not sound good." ActuallyI crossed them at 400hz first order with Al's Universal Network. Noproblems at all, sounded fine down there. That was with the lightweightA type diaphragms in them without the loading caps. Altec rated them for 500hz crossovers running every day for 12+ hours a day in theater use.Shawn Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted February 13, 2009 Share Posted February 13, 2009 Carl, Seti and JC, Thanks guys, I was starting to doubt my sanity. (ear) OK, please no jokes about my sanity. Not sure about Carl, (I think Bells) but we others have not used them with cornerhorns. The point being is that they perform well crossed at 400hz, (for the Khorn) even first order, and that they took (at the time) every kind of beating that I could give them.. without a hitch. I will say that now crossed low (450hz) with very steep slopes does sound better to me than a shallow slope cross point with the 902's. But then getting rid of horn/driver over-lap and smear at the point of cross always did. My fondness of the 902 comes from this one point, well maybe two. IMHO, they CAN deliver a nice quility sound in the 400-500hz range with large SPL's, but because they were intended to be a two-way driver and go out to 20K,... the upper mids from this driver in a three-way configuration to my ear, are hard to beat at any reasonable price point ..........Yes, I have listened to drivers that could best them......$$$$ tc Quote Link to comment Share on other sites More sharing options...
Blvdre Posted February 13, 2009 Share Posted February 13, 2009 Altec's test for diaphragm alignment on a 902 was 500hz tone played back at high volume to measure distortion and listen for buzzing. Shawn So I would expect Bill's process to be consistent with that. I'm even more puzzled. I stand corrected on the 400Hz (my memory's failed me agian, what a surprise). What slope was altec using to cross the 902 at 500? Carl, Yes the phenolics are in good condition, at least they appear to be - visually they look good, and the voice coils measure fine. The foam in the cap was rotten and foam crumbs were everywhere. I've blown the screen/ phase plug and gaps out with filtered shop air, cleaned the gaps with post its, re-tapped the cap holes, and replaced the cap screws with some nice stainless hex heads (heads ground to size). I still need to clean the old adhesive out of the caps and add new felt/ foam. Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted February 13, 2009 Share Posted February 13, 2009 "I remember reading Shawn's comments to Al, saying he crossed them at 500 1st order, played loudly with no problem, and Al replying that that might damage the drivers, and at the least, would not sound good." Actually I crossed them at 400hz first order with Al's Universal Network. No problems at all, sounded fine down there. That was with the lightweight A type diaphragms in them without the loading caps. Altec rated them for 500hz crossovers running every day for 12+ hours a day in theater use. Shawn Well it's about time that you stepped in here to bail-out my sorry a$$! After all it was you that gave me confidence in crossing them at 500hz or below using the sweet little A type diaphragms. BTW, many thanks for doing that. At that point I turned a corner in midrange quility. tc Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 13, 2009 Share Posted February 13, 2009 "So I would expect Bill's process to be consistent with that. I'm even more puzzled." Perhaps they got dropped in shipping and the alignment got thrown off? If you still have the 902s it might be worth testing alignment to see if that is the issue with yours. I know when I took the loading caps out of mine if I didn't align the diaphragm right it certainly buzzed from VC rub. Easy to fix that though. "Yesthe phenolics are in good condition, at least they appear to be - visually they look good, and the voice coils measure fine." The only way to really tell their condition is to acoustically measure them. In some 288s I bought the diaphragm looked fine and they measured fine on the multimeter. They sounded horrible and had something like half the bandwidth they should have had. New diaphragms fixed that right up. I posted measurements of this on the forum a few years back. Can not see work hardening and the multimeter just shows that the VC isn't open. Shawn Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted February 13, 2009 Share Posted February 13, 2009 JC is letting me rent to own his 511B/902 GPA combo and they are staying. You'll have to pry them from my cold dead ears. I didn't expect to like them this much. Perhaps I'm not listening loud enough but I haven't noticed any distortion. I have been working on getting the levels right fpr the LF HF but crossed steeply at 600 hz so far so good. I expected to need a tweeter but I really don't. This week I will be measure each of my autoformer taps so I can decide which to use ont the hf with my jubclone bass bins. " Perhaps I'm not listening loud enough but I haven't noticed any distortion." Seti, as I recall, Timmy Set Say had them up to 110db peaks on the Jub Clones. For a self stated 80db listener, how much more do you require? ( Ian is comming out, and he likes it loud...... when it it is clean and robust) tc PS: That little tube power amp of his gave them all that they required even at the SPL that I am use to. Very nice. tc Quote Link to comment Share on other sites More sharing options...
Blvdre Posted February 14, 2009 Share Posted February 14, 2009 Perhaps they got dropped in shipping and the alignment got thrown off? If you still have the 902s it might be worth testing alignment to see if that is the issue with yours. I know when I took the loading caps out of mine if I didn't align the diaphragm right it certainly buzzed from VC rub. Easy to fix that though. That's possible, but I would hope the diaphragms would be screwed down tight enough to resist movement, even when dropped (wonder what the torque spec is). Plus the drivers were bubble -wrapped. On the other hand, it wouldn't take much movement to mis-align. You never can tell with some of these shippers. "Yesthe phenolics are in good condition, at least they appear to be - visually they look good, and the voice coils measure fine." The only way to really tell their condition is to acoustically measure them. In some 288s I bought the diaphragm looked fine and they measured fine on the multimeter. They sounded horrible and had something like half the bandwidth they should have had. New diaphragms fixed that right up. I posted measurements of this on the forum a few years back. Can not see work hardening and the multimeter just shows that the VC isn't open. I've heard the aluminum diaphrams are the most susceptible to work hardening, and wonder where phenolics fall on that spectrum. The seller claims the diaphragms are recent replacements, and certainly check out as OEM. The coloration on one is a bit darker than the other though, which makes me think one replacement was probably sitting around a bit longer than the other. I would like to acquire some inexpensive means of taking measurements. Unfortunately, I don't own a laptop, so I'm limited to a stand alone device (and a small budget). Maybe a behringer deq2496? Quote Link to comment Share on other sites More sharing options...
Blvdre Posted February 14, 2009 Share Posted February 14, 2009 I also mentioned my inexperience with filters, because I was wondering if I mucked up the x-over. For a nominal impedance of 8 ohms, I figured a 33uF for a 1st order high pass at 600Hz. Quote Link to comment Share on other sites More sharing options...
seti Posted February 14, 2009 Share Posted February 14, 2009 JC is letting me rent to own his 511B/902 GPA combo and they are staying. You'll have to pry them from my cold dead ears. I didn't expect to like them this much. Perhaps I'm not listening loud enough but I haven't noticed any distortion. I have been working on getting the levels right fpr the LF HF but crossed steeply at 600 hz so far so good. I expected to need a tweeter but I really don't. This week I will be measure each of my autoformer taps so I can decide which to use ont the hf with my jubclone bass bins. " Perhaps I'm not listening loud enough but I haven't noticed any distortion." Seti, as I recall, Timmy Set Say had them up to 110db peaks on the Jub Clones. For a self stated 80db listener, how much more do you require? ( Ian is comming out, and he likes it loud...... when it it is clean and robust) tc PS: That little tube power amp of his gave them all that they required even at the SPL that I am use to. Very nice. tc Coming out what????? I just play that loud to show off when I have company : ) Or I pull a Coytee and crank the speakers inside so I can hear outside. If hanging out with friends chatting it is lower but if you add a beers the volume goes up and we sit there yelling at each other. Pretty funny really. Quote Link to comment Share on other sites More sharing options...
stereohermit Posted February 14, 2009 Share Posted February 14, 2009 I believe Altec went 12 db/ octave on the 902's see schematic below. The N500F is the one I'm familiar with, but this is somewhat similar except attenuation. Quote Link to comment Share on other sites More sharing options...
stereohermit Posted February 14, 2009 Share Posted February 14, 2009 trying to load proper schematic...sorry! N501-8A Crossover Network Schematic.pdf Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 14, 2009 Share Posted February 14, 2009 "On the other hand, it wouldn't take much movement to mis-align. You never can tell with some of these shippers." Thatis very true. Also after aligning the diaphragm tightening it down canchange its position slightly too. They certainly do buzz whenmisaligned with a VC rub, been there. It would be very interesting for someone that had buzzing at 500hz to try re-aligning the diaphragm to see if that helps or not.Shawn Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 14, 2009 Share Posted February 14, 2009 " but because they were intended to be a two-way driver and go out to 20K,... the upper mids from this driver in a three-way configuration to my ear, are hard to beat at any reasonable price point ........." If one is going to use them three way take advantage of the 902s bandwidth and push that crossover point up a bit to make life really easy for the tweeter. I always used the 902s two way but with the 288s I crossed them to 2404s at 8kHz. The 2404s sound better crossed up there. Shawn Quote Link to comment Share on other sites More sharing options...
Blvdre Posted February 14, 2009 Share Posted February 14, 2009 That is very true. Also after aligning the diaphragm tightening it down can change its position slightly too. They certainly do buzz when misaligned with a VC rub, been there. Yes, good point. I have that issue at work when aligning certain mechanical assemblies. As soon as you turn a screw, everything wants to rotate around that screw's axis. Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted February 14, 2009 Share Posted February 14, 2009 So........What I'm hearing, I think, is that it can be done. Will probably sound better. And the 902's wont go up in a puff of smoke[:'(] . I am contemplating the trachorns with the 902's. I am also contemplating Jubes, but one thing at a time. It doesn't sound like any of you who used the altecs actually used them on the the stock klipsch mid horns. Is it doable? Will the ALK universal network I have get me in the ballpark? I have read enough from you guys to learn that the k55 driver works very well if you just upgrade to the trachorn or 511. But I do know that the 902's are a very nice sounding driver, and I already own a pair, so........... I hope this isnt something that has been discussed to death already. So at risk of being a pain I ask those of you who have used the 902's on khorns, how exactly did you do it, and in your opinion was it a good upgrade? Thanks, Marty Marty: I guess that I am one of the few in here who has tried the 902s with Khorns. I also owned Trachorns at the time of my 902 purchase and was shocked at how good the Trachorns sound with 902s - having also compared the Trachorns to 511s and 811s that I also own. The Trachorn/902 combo has never left me wanting to reinstall tweeters up front. Some people are still skeptical about the Trachorn/902 combo, but that is only because they have never heard it. I use an active crossover with my 902s, crossing them over at 450 hz and 500 hz with no problems. I now cross them over at 800 hz because I have another midbass solution for the 300-800 hz range for my Khorns (Forte drivers...[]) I have also owned ALK universals and I believe that Al crossed over the squawker with a 12 db slope at about 400 hz with that network. That should mean that you will be ok. The only caveat that I have is that I would listen carefully with your ears for straining if you are inclined to lay into the volume (similar to my listening habits). Good luck. Carl. Quote Link to comment Share on other sites More sharing options...
Blvdre Posted February 14, 2009 Share Posted February 14, 2009 I guess that I am one of the few in here who has tried the 902s with Khorns. I also owned Trachorns at the time of my 902 purchase and was shocked at how good the Trachorns sound with 902s - having also compared the Trachorns to 511s and 811s that I also own. Carl. I'll back you up on that, Carl. I went from the 902/511 combo to gothover's tractrix, and the sound was much improved. Quote Link to comment Share on other sites More sharing options...
sfogg Posted February 14, 2009 Share Posted February 14, 2009 "As soon as you turn a screw, everything wants to rotate around that screw's axis. " Yes, that is exactly what they do on the 902. When I did mine I left them fairly snug and then lightly tapped them into position around the body of the diaphragm. That way when tightened them down they didn't really move. The 288s have adjustable locating pins that are seperate from the hold down screws which seems to prevent this. You use a paper spacer under the diaphragm to center it, lock in the locating pins then remove the diaphragm to take out the spacer and reinstall then tighten down the diaphragm hold in screws. Works well but isn't on the 902s. Shawn Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted February 14, 2009 Share Posted February 14, 2009 I guess that I am one of the few in here who has tried the 902s with Khorns. I also owned Trachorns at the time of my 902 purchase and was shocked at how good the Trachorns sound with 902s - having also compared the Trachorns to 511s and 811s that I also own. Carl. I'll back you up on that, Carl. I went from the 902/511 combo to gothover's tractrix, and the sound was much improved. How did you mount them? All of that blocking is in the way. I thought about getting longer bolts. Did you make a new mounting plate? Could you post photos? Thanks, tc Quote Link to comment Share on other sites More sharing options...
cjgeraci Posted February 14, 2009 Share Posted February 14, 2009 I guess that I am one of the few in here who has tried the 902s with Khorns. I also owned Trachorns at the time of my 902 purchase and was shocked at how good the Trachorns sound with 902s - having also compared the Trachorns to 511s and 811s that I also own. Carl. I'll back you up on that, Carl. I went from the 902/511 combo to gothover's tractrix, and the sound was much improved. How did you mount them? All of that blocking is in the way. I thought about getting longer bolts. Did you make a new mounting plate? Could you post photos? Thanks, tc Terry, not sure what you mean about the blocking being in the way. I have always mounted Altec drivers on Trachorns (902s and some 800 series) by removing the square mounting plate from the Trachorn, attaching the drivers to the mounting platform and then reattach the mounting platform. Not sure if it is the right way to do it, but it has worked for me. Carl. Quote Link to comment Share on other sites More sharing options...
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