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Altec 902-8b vs Selenium d220Ti on 511b horns

Wiseox

Wiseox

New Member
Would appreciate if anyone has had experience comparing the Altec 902-8b with other drivers, specifically the Selenium d220Ti?

I'm running a set of 511b horns with 220Ti drivers now, and must say, they sound great. But I got very lucky a couple of weeks ago, and scored a pair of proper Altec 902-8b's. Problem is, one of the 902's doesn't work. No current pass through, checked with an ohm meter, so I'm assuming I've got a cooked diaphragm. I priced out replacements direct from GPA, for $85 per, plus shipping.

Trying to decide if this is worth the investment. Also wondering if I should order a pair of diaphragms, or just replace my bad one. Both appear to be original/proper Altec diaphragms....just one is cooked.

Thanks in advance,

Doug.
 
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I have used both on the 511 and the 811 horns. The 220 comes off a bit shrill and tinny/thin sounding going below1.2~1.5 I think. The 902-8B is comfortable below 800hz and is rated to 500. My last experience with the 902-8b, a couple week back, was with that driver, the 511 horn, and a nice 15" Jensen woofer.

If it were me I would probably replace the phragm with an original Altec type. However I did get the chance to modify a set of 220's, inserting clay in the loading cap, that did work nicely and even out it's tonal problems! Still the power handling of the 902 was superior! The 220 can be an acceptable driver with some help and perhaps some horn padding as well!
DC
 
The 902-8B is comfortable below 800hz
Click to expand...
You'll find the number of applications where Altec used it below 1.2khz very limited.

902's were optimally designed for the Mantaray series of horns which had 7/8 inch throats to mate the 7/8 inch aperture of the 902.

511's have a 1 inch throat, and the 800 series drivers designed for it have a matching 1 inch aperture.

You can run 902's on 511's. But it's a less than optimum match as it puts a step in the throat and doesn't maintain a constant throat angle, the higher the XO the better. Altec ran 902's on 511 only for pro(read high power) applications and above 1.2khz.
 
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bowtie427ss said:
You'll find the number of applications where Altec used it below 1.2khz very limited.

902's were optimally designed for the Mantaray series of horns which had 7/8 inch throats to mate the 7/8 inch aperture of the 902.

511's have a 1 inch throat, and the 800 series drivers designed for it have a matching 1 inch aperture.

You can run 902's on 511's. But it's a less than optimum match as it puts a step in the throat and doesn't maintain a constant throat angle, the higher the XO the better. Altec ran 902's on 511 only for pro(read high power) applications and above 1.2khz.
Click to expand...

Am I mistaken- or did the Altec spec sheet on the 902-8B not rated it with a 500hz, second order crossover, IE with the 511 horn, the "A" model I agree with the 1.2hz crossover.

http://www.greatplainsaudio.com/vintage_altec/902A-
Series_hfdriver_spec_sheet.pdf

I thought the 902-8B sounded pretty good at 800/hz 2nd order!

DC
 
Sure, you can play them down to 500 on paper. You can even do it in practice provided you observe the power handling rules, and they will sound better than a lot of other 1 inch drivers out there. But, that's not their ideal application.

None of the radially slit phase plug 1 inch drivers play well down low(500hz). 800hz is still too low, for my taste. Compare them side by side at 500 hz with and 802D and see which you like better.

Don't get me wrong, 902 is a great great driver, but where it really shines is at the upper end of it's range, it likes a higher crossover freq than the heritage Altec drivers.

Take a look at how ALtec used them in OEM applications.
 
It may well be the application of the horn cell it's self in combination with that driver and or even other drivers.
Like an 1823 EV driver- also "rated" dow to 500hz- sounds terrible on the 511 anywhere near 500hz, and honestly not a whole lot better at 800hz. The 902-8B much better.
Both the 811 and 511 horns, while "rated" down to 800 and 500 hz just don't sound that good with any 1" driver I know of. I agree they do get much better at farther up the freq. band
I have had limited exposed with the 902-8B on other horn cells or wave guides, where it might sound even better at 800hz or lower! It's a BIG horn world out there and a lot of potential applications. As good as drivers are becoming these days it a wonder the 1" throat market is not more popular. I truely loved the Radian 475PB well over the 902, even a couple B&C were more impressive than the 902 as well.
But in the final word it's gotta be the ears that tell you the most. Be it the horn cell, the driver, the amp, the music type, what ever makes you pleased.
DC
 
Appreciate all the responses gentlemen. Sorry to respond back, so late.

I actually have the Mantaray horns, as my 902's are actually from a complete pair of 9872-8a's. I was debating using just the drivers with my 511 horns, that I have sitting on top of a pair of v1 Altec Santana's, with the 15" biflex woofers. But, maybe the route to go, is just keep them in the 9872's, and clean those up. Cabs are just so small, I don't have high expectations of the 9872's.

I have decided to order a single replacement diaphragm. I cracked open the good driver, and confirmed it's an Altec original. Not sense ordering a pair, if the other is still good. Just wanted to ensure they stayed matched.
 
Oh, I would also agree about the shrillness of the 220Ti's on the 511's. I actually used a small bit of foam (stolen from a pair of headphones), and stuck it in the throat of the 511's, and it really smoothed things out. I believe I got that recommendation from a thread here on AudioKarma.
 
I'll admit Sam, I haven't really tried them. Will give them a go, once we have both compression drivers up and running. The cabinets on the 9872's are a bit rough, but if the sound quality is there....maybe I'll fix them up, and keep them whole.
 
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