Al Klappenberger Posted January 21, 2006 Share Posted January 21, 2006 Tofo, "i'm going to be using the altec 902-8t's with this, al" "still a no-no?" ABSOLUTELY! You will blow them off the face of the Earth in short order If you really want to go 2-way with an Altec 902 and a Belle, Look at my AP12-500 or AP12-600. That's the minimum! The best would be the ES500T. Jw, Look carefull at your drawing mods. The .3 mH and 2.2 uF are still in the circuit! They shouldn't be. Al K. Quote Link to comment Share on other sites More sharing options...
tofu Posted January 21, 2006 Author Share Posted January 21, 2006 pff... can't win. oh well Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted January 21, 2006 Share Posted January 21, 2006 Tofu, Man, Aint reality the pits! []Al K. Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 21, 2006 Share Posted January 21, 2006 "ABSOLUTELY! You will blow them off the face of the Earth in short order" No he won't. I ran them with your Type A for awhile with no problem at all including full THX Reference Level. IB Slammin crossing at 400hz first order with the 902s and while cranking it *way* up (claimed around 120dB) the K33s died before the 902s. Thats on a Cornwall bass cabinet so the woofer was less efficient then on a LaScala but still illustrates that the 902 can handle the above crossover at pretty much any sane level in a home. Shawn Quote Link to comment Share on other sites More sharing options...
jwc Posted January 21, 2006 Share Posted January 21, 2006 Al was right. I left off one red "x". So there you have it. A first order if you want it. Adding the .3mHy parrallel will allow it to roll off quicker. It will still be close to 400Hz. I can't offer advice on the 902. I am the one who told IBSlammin to remove the 4uF cap from his Type B network to a 6.8uF cap so that the 902 of his would run at 400Hz. There is no bandpass on it so it is 400Hz and up. He told me as well that he can crank it. I can't recommend by no means that this is "ok". I don't know enough about the driver. HOWEVER! The 902 on his network is attenuated -6db to match the reflex/ported K33. This may allow more power handling ability. FWIW jc Quote Link to comment Share on other sites More sharing options...
tofu Posted January 21, 2006 Author Share Posted January 21, 2006 Al was right. I left off one red "x". So there you have it. A first order if you want it. Adding the .3mHy parrallel will allow it to roll off quicker. It will still be close to 400Hz. I can't offer advice on the 902. I am the one who told IBSlammin to remove the 4uF cap from his Type B network to a 6.8uF cap so that the 902 of his would run at 400Hz. There is no bandpass on it so it is 400Hz and up. He told me as well that he can crank it. I can't recommend by no means that this is "ok". I don't know enough about the driver. HOWEVER! The 902 on his network is attenuated -6db to match the reflex/ported K33. This may allow more power handling ability. FWIW jc so what would be the better choice? the first order that al suggested or running the .3mh in parallel as jwc said? personally i'd prefer second order for the steeper rolloff, but i'm not sure if jwc's suggestion is safe or not. Quote Link to comment Share on other sites More sharing options...
jwc Posted January 21, 2006 Share Posted January 21, 2006 Hey. I just noticed you are running the Mc 250 amp. What preamp are you using? Quote Link to comment Share on other sites More sharing options...
tofu Posted January 21, 2006 Author Share Posted January 21, 2006 Hey. I just noticed you are running the Mc 250 amp. What preamp are you using? no preamp yet.. it's not too high on my priority list Quote Link to comment Share on other sites More sharing options...
tofu Posted January 21, 2006 Author Share Posted January 21, 2006 so, can i get a concensus on this? "so what would be the better choice? the first order that al suggested or running the .3mh in parallel as jwc said? personally i'd prefer second order for the steeper rolloff, but i'm not sure if jwc's suggestion is safe or not." [] Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted January 21, 2006 Share Posted January 21, 2006 Shawn, You might be able to get away with running the 902 with my universal on the Cornwall. That's becasue it's attenuated way down to match the direct radiator woofer. Doing it on the Khorn or La Scala is sticking you kneck out a mile! You might get away with it, but you will just be lucky. The specks on the 902 cleary call for a higher crossover or a fater slope filter. To advise somebody else to do it is bad advice. BTW: connecting 0.3 mH to ground (across the 10 Ohm swamping resistor) to make the filter second order is a good idea, but the correct value is 3.0 mHy. 0.3 is WAY too low.Al K. Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 21, 2006 Share Posted January 21, 2006 "Doing it on the Khorn or La Scala is sticking you kneck out a mile! You might get away with it, but you will just be lucky." I did it that way for months without any issue at all and that is with diaphragms said to be fragile compared to the stock 902 diaphragms. The driver was attenuated 7dB to match the LaScala bass bin. " The specks on the 902 cleary call for a higher crossover or a fater slope filter. " The specs on the 902 are based on running reliably 12 hours a day, every day, and filling an 800 seat theater in the process. Are you trying to fill an 800 seat theater at home? Shawn Quote Link to comment Share on other sites More sharing options...
tofu Posted January 21, 2006 Author Share Posted January 21, 2006 whoops.. mixed up that decimal. all i have is the .30 from the original ALK. i guess the route i'll have to take is the schematic you X'd out for me Quote Link to comment Share on other sites More sharing options...
Deang Posted January 21, 2006 Share Posted January 21, 2006 The advantage of having LaScalas it that you don't have to force that driver into playing lower than intended. I would run it down to 600Hz first order and strongly respect the power rating of the driver. 1st order sounds the best to me personally -- but increased distortion becomes an issue much sooner than with higher order filters. Quote Link to comment Share on other sites More sharing options...
tofu Posted January 21, 2006 Author Share Posted January 21, 2006 The advantage of having LaScalas it that you don't have to force that driver into playing lower than intended. I would run it down to 600Hz first order and strongly respect the power rating of the driver. 1st order sounds the best to me personally -- but increased distortion becomes an issue much sooner than with higher order filters. yea but the idea was for me to modify this without buying new parts Quote Link to comment Share on other sites More sharing options...
Deang Posted January 21, 2006 Share Posted January 21, 2006 You need 44uF for a 600Hz crossover. You can use the four 2.2uF caps you have -- parallel two with each 39uF on each network. IF you like the sound -- buy four 22uF Jantzen capacitors from partsexpress. I don't think you're going to like the sound -- at least I didn't. Quote Link to comment Share on other sites More sharing options...
tofu Posted January 21, 2006 Author Share Posted January 21, 2006 you don't think i'll like the sound of the 600hz crossover point, running two-way, or going first order? Quote Link to comment Share on other sites More sharing options...
Deang Posted January 21, 2006 Share Posted January 21, 2006 Two-way. Quote Link to comment Share on other sites More sharing options...
tofu Posted January 21, 2006 Author Share Posted January 21, 2006 so many contradicting opinions. i guess theres only one way to find out Quote Link to comment Share on other sites More sharing options...
tofu Posted January 21, 2006 Author Share Posted January 21, 2006 3rd option is sell off tweeters when the moment is right and pick up a pair of bob's new creation whenever it comes out Quote Link to comment Share on other sites More sharing options...
Deang Posted January 21, 2006 Share Posted January 21, 2006 That's what I would do -- pick up a set of those tweeters and run them with the Altecs with the schematic I posted, and just add a single 2.2uF for each tweeter -- which gives you a full four octaves of coverage with the mid horn. You can mod the tweeter section later after you have a listen to see what the top sounds like. I think you'll find it sounds excellent. 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.