Beyond the Ariel

[Kolbrek]

Originally Posted by Pano

Here?
BEM Simulations

Yes. Sorry for forgetting the link.

[Pano]

Originally Posted by Lynn Olson

I design loudspeakers for my own satisfaction, not anybody else.

You're in an enviable position, Lynn. You know what you like and don't like, you know how to build what you want and you have no one to answer to but yourself. You've found yourself at the top of the audio food chain. Many DIYers share some of these traits, few share them all. Count yourself very lucky.

The "hints of greatness" in the Altec A5? Well, the large-format 288 on Altec's best horn, the big multicell, gets a lot of credit, along with the 416 woofer, which has an unusual old-school construction of an underhung voice coil, a light cone with a very effective edge-damping system (which provides freedom from breakup above 2 kHz, unlike most other 15" drivers), and an Alnico magnet. The crossover? Uh, no. The thin-walled plywood box? Uh, no. Those are problems, not assets, but you can't blame Altec for that. Filter design was in a very primitive state when the A5 was designed in the late Forties, and not much was known about box damping.

LOL! Oh so right you are. The stock version only gives a peek at what is underneath, it's a lot of work to bring out the fullest. But it's there. I was very lucky to have learned that 25 years ago in Paris. Some gals can get a make-over and you might think "It's just lipstick on a pig" while others can go from ordinary to super model. That's the story here.

Altec drivers and horns are works of art, the Altec crossovers were just a piece of work. My main objection to them isn't the parts quality, it's the values of those parts. They are mostly just textbook standard - not optimized to the speaker at all. Except maybe the model 19 crossover, everyone seems pretty happy with it. The very first step in getting these to sound good is a proper crossover. And yes, the cabinets rattled and buzzed and the ports were too big - but that is no hard to correct. Time consuming, but not hard. The design of the Altec 825/828 bass cabinet is pretty good, as long as it's built solidly. FWIW, I've seen more recent JBL cinema cabs that were far worse. How did they get away with it?

I've heard a lot of music and a lot of speakers in my life, the hotrod A5 still remains my favorite speaker. It's the best all-rounder I've ever heard. Sure, some speakers have more detail, higher highs - lower lows, bigger space, more pinpoint imaging, but none sound more like real musicians playing real instruments in a real space. That's what I want.

Your LTO should be very much that type of speaker. I hope it gets built by DIYers around the world and opens up a window into just how much music there is in the recordings we all know.

[Hylle]

Does anybody have complete TS data for the GPA416 16ohm Woofer, and frequency/impedance response they can publice?
I have tryed to contact GPA on mail without any luck. What is the price on this driver?

Lynn you describe it has some kind of special edge treatment to reduce peaks in the roll off area, how does that look like, how is it made?

[Pano]

It's sticky goo on the pleats. Great for picking up dust and fuzz.
Lynn can probably add the technical info.

[Hylle]

Thanks Pano, ok, so nothing new under the sun really..... Just good engineering! I am exited to see the TS data, while I feel it is fantastic high sensitivity in 16ohm Lynn is aiming for.

[ScottG]

Originally Posted by Hylle

What is the price on this driver?

Altec Lansing GPA 416 416-8B Alnico NEW | eBay

You would need to request the 16B.

That's actually from GPA (i.e. "direct" sale). Considering the materials alone vs. the marketplace and "similar" items, it's a bargain.

[thoglette]

Originally Posted by Hylle

What is the price on this driver?

Current score card, per speaker
GPA 416B-16 c. $350
GPA 288/AH-425 c. $350
Azure horn AH425 c. $275
RAAL Lazy Ribbon as a supertweeter c. $900
This is sans shipping.

Anyone planning 5.1?

[ScottG]

Originally Posted by thoglette

Current score card, per speaker
GPA 416B-16 c. $350
GPA 288/AH-425 c. $350
Azure horn AH425 c. $275
RAAL Lazy Ribbon as a supertweeter c. $900
This is sans shipping.

Anyone planning 5.1?

You know that the 900 RAAL isn't a prerequiste. While not the same level of performance, there are other long ribbons with wide dispersion that can offer a similar integrated dispersion pattern for considerably less expense.

It's also possible that you might prefer it without the super-tweeter.

[Pano]

The Radian 745 Neo is $300. The GPA Alnico 288 is $550. (That's each)
I still think you could do it for about $3000 the pair, with some DIY. Build your own horn and save even more (hint: paper maché)
You could hit $2000 for the pair if you're frugal. They won't be the exact LTO, but close.

[Truetone]

Papier mache is a good idea, but of course the problem is the mould. I give full instructions on my website (Azurahorn.com) but in reality it is more work than you would want to go to. An alternative method is to build up concentric discs of 2 ply cardboard (using he Le Cleac'h spreadsheet) and fill the steps.

The profile is not proprietary - anyone who wants to give it a go can enter the input data into the spread sheet and obtain it.

T=0.707
425 Hz cut off
one side wall angle 4 degrees
Throat 1.4"
Mouth diameter 420mm

Having just returned to the fold after a detour round TD2001s on 340 horns and Lowther PM2A on 204 horns I can say with confidence that the design choices that Lynn took wrt the 425 horn are spot on - hard to describe but you get that immediate feeling of it's just right.

martin