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Yeah, really...why is there a sudden switch in flare rate if these are pure exponential horns?

Why, oh why, is there such a rough surfaced brash transition from round to square right at the high compression point at the mouth of the driver? Don't stick any sensitive body parts into that throat lest it take your skin off with the casting flash and rough welds.

I tried to do this but I need a large format horn, know what I'm sayin'?

I agree that 511s can sound decent...until you hear something vastly superior.

And, even then, it is for each of us to decide what we are satisfied with. There are many satisfied 511 users.

Me, as I said on some forum, maybe diyaudio, I think they are great...for using as a funnel for an oil change. Boy, that went over well with the fanboys!

I take the strong contrary position to point out to interested parties that the 511 is far from the be all and end all of horns, and in fact is only fair at best. This is to say that if you like the 511, keep looking for a better one because there is a long way up, and if you can't stand the 511---a not uncommon reaction-- don't give up on horns for that reason, because there is a long way up.

It is a pro-bono public service gesture.

Other peoples system preferences are like their sexual preferences. I say do whatever you want, as long as I don't have to watch!!

Has anyone here made a fiberglass horn. You know, make a mold (plaster, high density foam, etc.) and lay it up with fiber glass cloth and epoxy like you would build a boat.

Gary Gill Has horns that are made in that fashion but they are not for compression drivers.

Tom

That sudden transition in the throat area seems to be a design feature, not a flaw.

Here is the excerpt from Altec literature:

511B/811B:
Exponential expansion and straight throat configuration ensure uniform control of the sound dispersion pattern -- 90 degrees horizontal by 40 degrees vertical -- and exacting reproduction of the middle and high frequencies.

http://alteclansingunofficial.nlenet.net/proloudspeakers/sectoralhorns/511B&811B-Data.pdf

It was design back then as a way to get a uniform desired radiation pattern. However, it's also a diffraction horn and all that entails. That's considered a flaw against sound quality.

You beat me to it

Roscoe

_________________
I can explain it to you, but I can’t understand it for you.

Job #1 for a pro horn is dispersion control, i.e. defined coverage. The Altec sectorals will give you that. You got to light up the seats or else you failed.

They were obviously quite successful and in production for many years. Possibly the most popular and commonly-used horn of all time.

I am a bit puzzled that these rather-average horns were used in major recording studios but a primary characteristic of a recording studio monitor is to be predictable and repeatable, and Altec sectorals were that. An overgrown Yamaha NS-10, sorta. And they do resolve a lot of "detail," particularly compared with most of the other 50s-60s gear. They did the job to the satisfaction of top pros, it seems. Sounding too good is often cited as a drawback for a monitor.

Altec's generally, and the 511/811s specifically, wide acceptance and long reign in pro audio is testament to the fact that they knew what they were doing and many pros agreed.

The Altec engineers weren't designing for audiophiles per se, but they did come up with some excellent parts for home listeners to re-purpose. However, you have to evaluate the stuff carefully on a case by case basis--- just like everything else.

By that definition, all sectoral horns are flawed, right?

Again from Altec literature:


Probably directionality of the higher frequencies is the reason almost all the direct radiating speakers have very small sweet spot for soundstage imaging.

I am not suggesting that sectoral are better than other horns or speakers of any other kind. Just trying to understand. What sonic characteristics of sectoral (not just 511Bs) horns is considered flawed?

Read carefully... Pooge said that DIFFRACTION horns were a flaw against sound quality. Not all sectoral horns are diffraction horns, and not all diffraction horns are sectoral....

The 511/811 horns just happen to be both.

Roscoe

_________________
I can explain it to you, but I can’t understand it for you.

Oh! Sorry I was reading it as "dispersion". Now, I get the point pooge is making.