sootshe Posted October 1, 2010 Share Posted October 1, 2010 I'm going to change the set up in my La Scala's & run them with an Altec 902 as the mid driver with one of Al's ES crossovers. Not sure yet whether I'll run 2 way or 3 way, but will experiment with both options. Does anyone have any conclusive data for the upper frequency limit of the La Scala bass bin to enable me to select the best crossover point? Many thanks, John Quote Link to comment Share on other sites More sharing options...
Blvdre Posted October 1, 2010 Share Posted October 1, 2010 Bob was just asking about this (plot of lascala bin). I tried a GPA902 with a gentle slope x-over, and I just couldn't cross the 902 low enough, without casuing distortion, and I ended up with a hole in the response. The ES x-overs might just be the ticket. I ran my set up as a two-way with some high frequency contour to flatten the HF, and, aside from the response hole, it sounded great. 1 Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 1, 2010 Share Posted October 1, 2010 John, I have never run a curve on the LaScala, but the Belle woofer is similar and I have crossed mine over at 700 Hz for a while. It worked fine. I think 600 Hz would be both safe for the 902 and would be well within the upper limit of the bass horn. You will need an ES network to keep the lows off the 902 though. Al K. Quote Link to comment Share on other sites More sharing options...
sootshe Posted October 1, 2010 Author Share Posted October 1, 2010 Bob was just asking about this (plot of lascala bin). I tried a GPA902 with a gentle slope x-over, and I just couldn't cross the 902 low enough, without casuing distortion, and I ended up with a hole in the response. The ES x-overs might just be the ticket. I ran my set up as a two-way with some high frequency contour to flatten the HF, and, aside from the response hole, it sounded great. Yes, they do sound great. I've just hooked a pair up & running them through the standard universal (at very low volume). They sound much more detailed & refined. If 500 is the limit of the bass bin then I may have to use loading caps as well as the ES crossover to fully protect the drivers. Hopefully someone will have the data on these cabs....I can't believe that after 40 odd years no one hasn't figured out the upper limit of this horn. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted October 3, 2010 Share Posted October 3, 2010 I'm sure someone has good data on the La Scala cabinet. I'm not home right now, so don't have the exact number, but I am crossing my LaS bass bin somewhere between 500 and 600Hz in two way configuration. This is with an active crossover L-R 48 slope which is the steepest I can go with my crossover. I use it for my center channel so it is used for dialogue quite a bit. I have not noted any problems at this frequency range. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted October 3, 2010 Share Posted October 3, 2010 I ran across this plot in my files. I have no clue where I got it from or who did the work, but it may answer some questions for you. Quote Link to comment Share on other sites More sharing options...
sootshe Posted October 3, 2010 Author Share Posted October 3, 2010 I ran across this plot in my files. I have no clue where I got it from or who did the work, but it may answer some questions for you. Thanks Rudy.....is anyone able to interpret this for me?....is it meaningful data? Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 3, 2010 Share Posted October 3, 2010 What horn are you going to have the 902 on? I ran 902s w/511Bs on my LaScala's using the ALK Universal networks along with the K77. The LaScala's were also high passed at 80hz. 902s handled it fine. Later on I switched to two way using the ES600s which was a great combination. Shawn Quote Link to comment Share on other sites More sharing options...
sootshe Posted October 3, 2010 Author Share Posted October 3, 2010 What horn are you going to have the 902 on? I ran 902s w/511Bs on my LaScala's using the ALK Universal networks along with the K77. The LaScala's were also high passed at 80hz. 902s handled it fine. Later on I switched to two way using the ES600s which was a great combination. Shawn Shawn....I was going to use my ALK Trachorn.....and yes I was thinking the 600's also. I did notice a gap in the response when I connected the 902's directly to the Universals. Quote Link to comment Share on other sites More sharing options...
djk Posted October 3, 2010 Share Posted October 3, 2010 "is anyone able to interpret this for me?.." It gets wierd above 450hz or so, that would be my choice for an ES crossover. I have used the LS above there, but it does not sound the best. I even tried corner reflectors in two pair I built from scratch. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 3, 2010 Share Posted October 3, 2010 "It gets wierd above 450hz or so, that would be my choice for an ES crossover." I'm quite sure the Es400 network, which was designed for the Khorn, would work in the LaScala. It doesn't have quite as sharp a slope as the ES500 or ES600. I could easy do an ES450 design and post the schematic of it turns out to be the right place. I think it will limit your choice of drivers though. I don't know of any driver but the K55 that will run safely down at 400Hz on a 1-inch horn. I would definitely be scared to run an Altec 902 that low. Al K. Quote Link to comment Share on other sites More sharing options...
seti Posted October 4, 2010 Share Posted October 4, 2010 There are some 902's that go down pretty low and some start to dive early and should be crossed at 1khz. I was told the difference was the loading cap. I really like the 902's. I'd really like to try the 511b/902 combo on a cornwall as a two way. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 4, 2010 Share Posted October 4, 2010 More important than if the driver will go down low enough is the distortion down low. I did some intermod test on a JBL 2426h, which I think is a more robust driver than the Altec 902. It generated major distortion even below 500 Hz. I really think the 902 should not be used below about 600 Hz even with an extreme-slope crossover. I would need to actually run tests on one to be sure about that though. Al K. Quote Link to comment Share on other sites More sharing options...
Coytee Posted October 4, 2010 Share Posted October 4, 2010 Not sure yet whether I'll run 2 way or 3 way, but will experiment with both options If it matters or helps to know... it seems that for the 2-way "JubeScala" the crossover used for the LaScala bass bin and the K402 horn is at 420 hz (LR/24) on the bass bin and 470 hz (LR/24) on the K402/K69. I don't know why each section uses a different frequency. I speculate it has something to do with electrical crossover verses acoustic crossover? I don't know if this helps you at all but I figure since this is what Klipsch is doing there is probably some logic in it. Side note, I just looked up the JubeScala when being used with the K510/K69. It too is crossed at the same values as above. Quote Link to comment Share on other sites More sharing options...
sootshe Posted October 4, 2010 Author Share Posted October 4, 2010 Not sure yet whether I'll run 2 way or 3 way, but will experiment with both options If it matters or helps to know... it seems that for the 2-way "JubeScala" the crossover used for the LaScala bass bin and the K402 horn is at 420 hz (LR/24) on the bass bin and 470 hz (LR/24) on the K402/K69. I don't know why each section uses a different frequency. I speculate it has something to do with electrical crossover verses acoustic crossover? I don't know if this helps you at all but I figure since this is what Klipsch is doing there is probably some logic in it. Side note, I just looked up the JubeScala when being used with the K510/K69. It too is crossed at the same values as above. Thanks Coytee & others,.........I tend to agree....there must be a valid reason that Klipsch uses this crossover point & I think the 902 used down that low is a stop gap measure at best..........You can use the 902 at 500Hz providing you use a loading cap, but some say that this affects the sound.............With all I've been through with these speakers I don't want to go for a part remedy, at least trying the 902's gave me an idea of what to expect........Looks like the larger format is the way to go & I really like the look of the GPA 390 series......Thanks again, John [] Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 4, 2010 Share Posted October 4, 2010 Altec used 902s in commercial theaters at 500hz second order all day every day. They can take it. When I was using the ES600s I had the loading caps removed. The 'problem' with the larger format Altec's is they really limit you to three way operation. I had 288s but they didn't have enough on the top end to run two way. The 902s can. I think the 390s have less top end then the 288s. If you want to go large format check out the Peavey 44xt which is either a 1.6" exit or a 2" exit. With its 4" diaphragm it can easily handle lower crossover points and it has plenty of top end for two way operation. Those on K510s replaced all my Altecs and the JBL 2404s I was using with the 288s. Shawn Quote Link to comment Share on other sites More sharing options...
sootshe Posted October 4, 2010 Author Share Posted October 4, 2010 Altec used 902s in commercial theaters at 500hz second order all day every day. They can take it. When I was using the ES600s I had the loading caps removed. The 'problem' with the larger format Altec's is they really limit you to three way operation. I had 288s but they didn't have enough on the top end to run two way. The 902s can. I think the 390s have less top end then the 288s. If you want to go large format check out the Peavey 44xt which is either a 1.6" exit or a 2" exit. With its 4" diaphragm it can easily handle lower crossover points and it has plenty of top end for two way operation. Those on K510s replaced all my Altecs and the JBL 2404s I was using with the 288s. Shawn Shawn.......good to hear comments from someone who has used the large format Atec drivers.....the 288's go to about 15K & the 390's top out at about 6 or 7K, so yes, you need to run them 3 way, which is not really a problem as I already have the tweeters. Interested in your comments on the Peaveys.....did you find they had the same quality of sound as the Altec combinations? ............I know Altec did use the 902's at 500, but their recommendation is to use the loading cap......with all these options it certainly gets very confusing...........I'm sooo close to the sound that I'm after but I can't live with the resonances at certain frequencies of the K55........have been talking to Bob about the 2 piece phase plug design in the K55, which he says is a lot smoother.....if that cures the problem then it will make things a whole lot easier......Cheers, John [] Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 4, 2010 Share Posted October 4, 2010 ".good to hear comments from someone who has used the large format Atec drivers.....the 288's go to about 15K " More like useable to 10 or 11k IMO with new diaphragms from Great Plains. They were too soft like that as a two way. With the used work hardened diaphramgs that came with the drivers they were barely getting to 5k as I recall and couldn't go under 1000hz or so. Measurements are on the forum somewhere. With the good diaphragms I crossed at 8k to the JBL 2404s. The 902s go much higher, I ran them two way. "the 390's top out at about 6 or 7K" If those are like the 290s I think it is more like 4500 or so. That limits tweeter choices somewhat. "nterested in your comments on the Peaveys.....did you find they had the same quality of sound as the Altec combinations?" The Altecs (and JBLs) are gone, still have the Peaveys. I have been very happy with them. If you want some reading material...... K55 vs 902http://forums.klipsch.com/forums/p/32246/276842.aspx#276842 288 diaphragms:http://forums.klipsch.com/forums/p/62120/607799.aspx#607799 288 and 902shttp://forums.klipsch.com/forums/p/75942/748993.aspx#748993 Peavey measurements in here starting on page 4:http://forums.klipsch.com/forums/t/84288.aspx?PageIndex=1 Shawn Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 4, 2010 Share Posted October 4, 2010 Shawn, Good old 20-20 hindsight! I wish I had done intermod distortion tests on that 902 you sent me long ago like I did on the JBL 2426 just a few months ago. It would answer a lot of questions. I got an email minuets ago from a fellow who just got a set of Belles with the Trachorn, 902 and my Kit Universal networks in them. He is having trouble with distortion, I suspect, although he describes it as harshness. I suspect a 1st order crossover at 400 Hz is just pushing the 902 to far! Al K. Quote Link to comment Share on other sites More sharing options...
sootshe Posted October 4, 2010 Author Share Posted October 4, 2010 Shawn.....very interesting reading.....hard to believe you gave up all those Altecs........those Peaveys must really fire along! Thanks, John Quote Link to comment Share on other sites More sharing options...
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