Altec 290 vs. 288 drivers

[George Roland]

In a home audio system, as a midrange driver, attached to an Altec 311-60 or 90 horn, what would go into deciding whether a 290 or 288 driver would be best?
I am curious about this because the 288 G and K drivers cost so much more than the 290 what makes them so much more popular/costly?
Why do alnico magnets seem preferable to ferrite?
Why do metal diaphrams seem preferable to phenolic?
Thanks,

George

[Old Guy]

As a midrange driver I consider the 290 superior. Top end only goes to about 5-6 khz- tweeters are a must. may use the 288 without tweeters.

Metal diaphragms tend to be brighter than phenolic. I use to have a pair of old RCA drivers that were phenolic and sounded quite good however.

And a driver I like a lot- BMS- uses polyester.

You pays yer money, and you takes yer choice....

[George Roland]

When you say the 288 sounds brighter do you mean that it reproduces a higher range of frequencies or that in the same range of frequencies as are reproduced by a 290, it sounds brighter?
I realize this is somewhat subjective.

Thanks for your views!

Best,

George

[Old Guy]

The 288 goes out higher.

The answer to that would be- what is your hf crossover? At 4khz I doubt there a difference, at 10 khz the 288 is going to do a better job-
tje 290 is good up to about 5-6 kz I wouldn't go beyond that.

[George Roland]

I'm planning on using this combo as the squawker in a Klipschorn system. The K-horn crossover to the tweeter is ca. 4,500Hz, so I think I should be okay.

I would also be interested in your take on the 311/90 degree versus the 311/60 degree horn. I have had several people who had heard both these horns with the 290-16K driver suggest the 311/60 to be better in a domestic setting in the corner atop K-horns because the radiation pattern produced less troublesome wall reflections in the narrower horn.

Thanks,

George

[Old Guy]

That question I'd like to defer to GM- hopefully he'll read this-

Certainly makes sense but I've used 90's with no ill effects- the 60 horn can be bought cheaper sometimes, so that is an attraction.

[GM]

Originally posted by George Roland:
I would also be interested in your take on the 311/90 degree versus the 311/60 degree horn. I have had several people who had heard both these horns with the 290-16K driver suggest the 311/60 to be better in a domestic setting in the corner atop K-horns because the radiation pattern produced less troublesome wall reflections in the narrower horn.

<font size="2" face="Verdana, Helvetica, sans-serif">Greets!

I find this hard to believe since the 311-90 is already beginning to beam at ~700 Hz and if Altec's polar plots are to be believed it's actually better down low than the 311-60! Regardless, in the horizontal plane all the sectoral horns are inside 90 deg from 500 Hz up, so no side-wall reflection issues of note. All I can conclude is that these folks prefer the more uniform pattern over a wider BW of the 311-60 Vs the 311-90 and I tend to agree based on my own experiments with different patterns.

The trade-off though is that due to the tighter pattern control with a modified expo expansion it has a more 'colorful' (distorted) sound to my ears, so no 'free lunch'.

GM