nola Posted July 29, 2009 Share Posted July 29, 2009 Thx Blvdre: I found the P-audio adapters at usspeaker.com and loudspeakerplus .com. Is that who you buy from? I called Great Plains Audio in OKC. They are the main parts forlks for Altec. They seriously warned me against driving the 511 horn/902 driver - 8 ohm (expect 6-7 ohms on the multimeter) combo below 500 Hz. In fact they suggested a higher crossover frequency if at all possible, perhaps 800 Hz. I was warned that the Altec type diaphragms (at $100 each) will not hold for long at 400 Hz, and only to drive them quietly and only for short periods during testing out the Altec combo. The Altec combo should be good up to 20 kHz, thus potentially obviating the need for a tweeter. They know about Klipsch folks doing mods, but could not comment further. The K33 LaScala or Khorn bass bin is good to 350, maybe 400 Hz from what I have read here. Using a xover at 500 Hz might be a bit of a stretch. However a single 500 Hz xover for K33 and 902 might the only viable compromise. I would anticipate using the cheapest and easiest to make passive xover from the many parts I now have, which include the Klipsch AAs and ALK Unis. I have never seen a posting about a 2 way passive xover on this or any other forum, for a 500 Hz xover, woofer at 4 ohms and midrange driver at say 6 or 7 ohms. Perhaps later this year I might get an active xover. A separate subwoofer xover / amp would be used, at about 60 Hz, I think. Thx NOLA Quote Link to comment Share on other sites More sharing options...
Blvdre Posted July 30, 2009 Share Posted July 30, 2009 Thx Blvdre: I found the P-audio adapters at usspeaker.com and loudspeakerplus .com. Is that who you buy from? Yes, I bought mine from usspeaker I called Great Plains Audio in OKC. They are the main parts forlks for Altec. They seriously warned me against driving the 511 horn/902 driver - 8 ohm (expect 6-7 ohms on the multimeter) combo below 500 Hz. In fact they suggested a higher crossover frequency if at all possible, perhaps 800 Hz. I was warned that the Altec type diaphragms (at $100 each) will not hold for long at 400 Hz, and only to drive them quietly and only for short periods during testing out the Altec combo. The Altec combo should be good up to 20 kHz, thus potentially obviating the need for a tweeter. They know about Klipsch folks doing mods, but could not comment further. I purchased a new pair of 902 from great plains a while back, and they sounded a bit ragged crossed at 500Hz on a first order filter, so I bumped up the crossover point, and they sounded fine (very nice in fact). Others here have used them down to 400Hz without a problem. I have to wonder if the GPA diaphragms arelighter than the original altec. Lighter is good forhigh end response, not so much down low. The K33 LaScala or Khorn bass bin is good to 350, maybe 400 Hz from what I have read here. Using a xover at 500 Hz might be a bit of a stretch. LaScalas are OK to 500Hz - that's where mine are crossed and they sound fine. I'd like to see a trace of the upper roll off though (maybe a search is in order). However a single 500 Hz xover for K33 and 902 might the only viable compromise. I would anticipate using the cheapest and easiest to make passive xover from the many parts I now have, which include the Klipsch AAs and ALK Unis. I have never seen a posting about a 2 way passive xover on this or any other forum, for a 500 Hz xover, woofer at 4 ohms and midrange driver at say 6 or 7 ohms. Perhaps later this year I might get an active xover. If you want to cross at 500Hz, I think your best bet would be to use a higher order crossover to both protect your mid and smooth out the response. A separate subwoofer xover / amp would be used, at about 60 Hz, I think. Thx NOLA Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted July 30, 2009 Share Posted July 30, 2009 NOLA, Do you already own the Altec 511's. If not, you might want to consider other comparably priced horns that have a larger throat. The difficulty you are running into is that at low frequencies a good deal of air must be moved and this is a function of the driver excursion and the size of the throat. This explains the advice you received from GPA. It may also be difficult to choose diaphragm that can at the same time be tough enough for the lows and also have a high frequency extension. Unfortunately there is no free lunch. Are you going to be running this as a 3-way or a 2-way system? Do you need to limit yourself to relatively shallow slopes on the cross over? If you are married to the Altec 511's, then read the threads by SFogg. He tackled a similar issue in a wise and systematic way. -Tom Quote Link to comment Share on other sites More sharing options...
Dylanl Posted July 30, 2009 Author Share Posted July 30, 2009 Still hoping to get this answered..... How do I know the polarity since there are no markings? Which is positive and negative? There are green and brown wires. Quote Link to comment Share on other sites More sharing options...
Dylanl Posted July 30, 2009 Author Share Posted July 30, 2009 Ok I figured it out on my own. Brett Quote Link to comment Share on other sites More sharing options...
nola Posted July 30, 2009 Share Posted July 30, 2009 Tom: Thankyou. I ain't married....hehehe.....LOL. Just finished fixing a sub amp and starting even more projects here, oy vey...... So I am a bit beat now. I have 511s, they just need a good cleaning. I have 902-8 ohm drivers as well. Got some new nuts and washers for them. Will also make a thin plastic "gasket" at the meeting point of 511 and 902 from some drawer liner material. They measure 6.8 and 7.3 ohms. Intent is 2 way. But if I can't do that, will try to figure out best 3 way components. Too many posts from SFogg to sort through now, but will try this weekend. Canyonman bought the 2 inch wooden horns and drivers. Can't wait to hear them. BTW the 511s, etc are intended as K horn mods. I do own LaScalas as well, but want to futz with the KHs first. I think Don Richards answered another of my posts saying that he used an A network. I will check rolloff of the bass bin and Klipsch mid horn and tweeter and ALK wooden horn and the 511 all separately via ALK Uni and AA networks. With the new software (Room EQ Wizard) this should go fast (I hope). I can further modify my xovers, if I can figure out what and how much to change. There are multiple formulas and filters for xovers-and have no idea what to use. Any further specific info appreciated. (BTQ, I measured the K33s at about 4 ohms). Quote Link to comment Share on other sites More sharing options...
Blvdre Posted July 30, 2009 Share Posted July 30, 2009 So Dylan, what's the answer? Brown positive is my guess. Nola, I thought the 902 sounded much better on the wooden tractrix, as compared to the 511. I'll be interested to see what you think. I ended up using some contouring in my passives to flatten the response of the 902 (yielded better high-end for two way operation). Quote Link to comment Share on other sites More sharing options...
Dylanl Posted July 31, 2009 Author Share Posted July 31, 2009 I just tested with a 1.5 volt battery and watched if the diaphragm went in or out. Should have just looked closer from the start. Quote Link to comment Share on other sites More sharing options...
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