Pretty Reasonable 411-8A's

GM · December 26th, 2015, 07:44 PM

Originally Posted by bowtie427ss

History has taught me to assume very little with Altec, and to be careful about posting assumptions. In all fairness, i've never had a 909 in my hands long enough to put the ruler across it.

I want to assume that a 902 and 909 use the same motor assembly. Maybe a member who has one easily accesible would measure one for us

...................... and yes, my memory and my eyesight are not what they used to be. I expect it's a downhill run from here.

Agreed, especially after the late '60s, though I was referring to your post measuring the 902 as 7/8" to match up to the small Mantaray. The 909 is 1" as shown on its data sheet, though in later years the 902 is listed as 1" also, but no clue if it's a typo or there's a later version 902 with a 1" to confuse us. Maybe Bill can set us straight.

Well, it's been more like falling off a cliff for me, so have to Google myself to find out a lot of what I once knew now that so much of it is locked up in a damaged HD and its backup.

Anyway, you're right about any mis-match between the horn/driver being a no-no [doesn't matter which way, sound is AC, so a double 'hit'] since it causes reflections that makes a mess of the HF response and why I ultimately wound up align honing a pair [among other things], replacing the cardboard gasket with an alum. one with wax paper gaskets to ensure a tight seal [normally another no-no].

GM

**magnarc** · December 26th, 2015, 10:53 PM

Thought the 902-8A was 7/8 and the 902-8B and 909-8A were 1 inch. The 902-8A pair I have are 7/8 inch throat. Don't have B's or 909s to compare.

Why oh why Altec did this 7/8 on that one driver I don't know.....

GM · December 27th, 2015, 10:57 AM

It apparently was part of this Mantaray system design: http://www.lansingheritage.org/image.../931/page1.jpg

GM

**magnarc** · December 27th, 2015, 10:38 PM

Ahah! That makes sense! Know of the horn, hart read closely that it was 7/8

**bowtie427ss** · December 28th, 2015, 09:59 AM

But, but, but................... we need somebody to measure a 909. And it would be nice if we could get somebody to measure the throat on MR-994 as well. I don't trust the drawings, only what i measure. I'd like to buy a pair of 994's for use with 802's, the drawing says the 994 has a 1 inch throat, as does the drawing for the 909 in the link below.

http://alteclansingunofficial.nlenet...909-8AData.pdf

**Phil-G** · December 28th, 2015, 10:10 PM

last time i measured a mr931 it was 7/8".

**bowtie427ss** · December 29th, 2015, 08:36 AM

Originally Posted by Phil-G

last time i measured a mr931 it was 7/8".

I think this is pretty well understood along with the MR-902T horn, i've measured them myself. We specifically need to know about the 994 horn, and 909 drivers, or at least i need to. I don't want to lay out the cash for a pair of 994's plus shipping only to learn that i'm stuck using a 900 series driver. I'm torn between 994's and buying adapters and using a pair of MR-94, but they are a little obtrusive in a smaller space.

**Phil-G** · December 29th, 2015, 08:49 AM

i just bought a pair, 994as are 1"

**bowtie427ss** · December 29th, 2015, 09:00 AM

Originally Posted by Phil-G

i just bought a pair, 994as are 1"

Excellent, thank you Phil.

**magnarc** · December 29th, 2015, 09:18 AM

I believe the 902-8A was the only 7/8. The 8B then was 1" and the 909 came after that at 1". Though there might have been a few random early 8Bs at 7/8 someone said.

Is the MR902 horn 7/8? It has the 902-16A on the back yes?