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Altec 902s on the Way!!


cjgeraci

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.............. It turned out that Bill became sidetracked with other customers after I spoke with him on Monday, and did not switch out to the 16 ohm versions. ...............

Funny how that happens with Bill. Mine also. However he DID fedx the 16's to me overnight.

.......I have not really laid into 902s at extreme levels yet,...........

(Said with a NYC Italian Accent) Don't worry about it. I have.

Hammered the 902-16a first order crossed at 400hz. Noooooo prob! Go for it.

Enjoy

tc

Thanks, Terry. Recently, I looked again at your emails from earlier this year concerning the 902. You were my inspiration to go ahead and take the plunge.

As to volume, they will get a heavy workout this weekend. Time to fire 'em up and see what they'll do.......................................

Carl.

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In addition to his own fine crossovers, Al also appreciates the active approach. He knows about my latest experiment and has voiced his approval over in AK.

Al considers the 902 an excellent driver, and he just suggested that I not cut the 902 too low. I also miss him in here, but we still have him in other forums.

Carl.

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Well some genius,s can be tempermental... And cut off there own noses to spite there face.. When your a guest in some body elses home (forum) you need to be civil. I just kicked out a friend of 40 years because of that. You can make allowences for so long then friendships will snap... Its sad.

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"Al considers the 902 an excellent driver, and he just suggested that I not cut the 902 too low."

Al is a little over cautious regarding the 902. I ran them with his Type A for awhile (and ones with lighter diaphragms) and they had no problem with the 400hz crossover in a home setup.

Have fun with them, they are a very nice driver. FWIW the Al's ES600 was designed specifically for the 902... I had sent him one to test out. Great combo run 2 way on the LaScala with a 511B.

Shawn

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Well some genius,s can be tempermental... And cut off there own noses to spite there face.. When your a guest in some body elses home (forum) you need to be civil. I just kicked out a friend of 40 years because of that. You can make allowences for so long then friendships will snap... Its sad.

Can't argue with that, Maron.

tc

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"Al is a little over cautious regarding the 902."

Considering the cost of the diaphragms, I would be careful in what I recommend for others too.

What's loud is relative. Loud to you is different than loud to me. Room size is a factor. Program material is a factor.

Aluminum work hardens and the sound gradually changes, not enought to notice on a week-to-week basis.

This process is sped up by how far the diaphragm has to move. To play the same volume level, the diaphragm has to move four times as far to go down one octave farther. JBL rated their 1" aluminum drivers at 30W/800hz, but only 10W/500hz. The real issue is not 500hz vs 400hz, but the crossover slope. How far is the 250hz down? The 10W/500hz rating is assuming a 12dB crossover. With a 6dB crossover, to have no more than the same energy at 250hz as you did with the 12dB crossover you would have to restrict the input power to 2.5W! With a 24dB crossover you could run much higher power, but the Nomex voice-coil former will burn up if the long-term average power exceeds about 30W.

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Yes and the back cover on the 902 is,nt made of glass to see the voicecoil glow in the dark before burn up. About every 5 yrs I replace my diaphrams on highfrequency drivers....You,d be suprised at the sonic improvement from old tired voicecoil phrams.....You can only get so much mileage out of a driver before changing those tires (phrams). At some concerts they change diaphrams after each performance.

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Ok, they've been through their paces for some days now and as I put it to Maron earlier this evening, "they kick a#$."

Now, I have some idea of what the Jubilee crowd is hearing with a decent two way. And I continue to be pleased with this active stuff.

For the record, I am currently crossing the 902s over at 500 hz with a 18 db slope. No strain is heard.

Enclosed is a pic of a 902 compared to the smaller K55V.

post-13160-13819349793492_thumb.jpg

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  • 2 weeks later...

Hey, even with my 20+ year old, work hardened 902-8B drivers, I still swear by them. Mounted to the 511B's, being crossed over at 900Hz and being EQ'ed a little bit in their current state, these horns do NOT sound like horns at all, except for their efficiency and effortless projection into the room.

Posted Image

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Hi Bruce

Yeah, it's been a while. I don't know about my bro though. I thought he was still on here on a regular basis.

Anyway, 900Hz seems like a good xover point at the moment. It's not a definate yet as I haven't done any measurements at 900Hz. And just in case you didn't notice by the pic (since it's a straight on shot), these are open baffle speakers using 2 Usher Audio 15HM drivers per side. I still have that 51uF Solen cap hanging off the rear of the 902-8B drivers to soak up any possible turn-on thump if there was ever to be one, just for safety. They have solid output down to about 35Hz or so and sound really good. They turned out much better than I was expecting. You can't been that open baffle naturalness.

Posted Image

This was the last test I ran with the xover point up at 1kHz.

Posted Image

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