Altec 820A Corner horn??

[Dylanl]

Does anyone know where I can get a working set of plans for this corner horn? I am also looking for the freq. range of this unit. I have the original brochure but I am looking for the real feel info.

Thanks

[Tom Brennan]

Dylan----"How To Build Loudspeaker Enclosures" by Davis and Badmaieff has the plans.

[Dylanl]

This is the one I am talking about:

[Dylanl]

Tom I think this is one the plans are refering to. I also have that set of plans and I have that book. What is the difference in the two this one and the one I show in the other picture. Is there anyone that has currnetly reproduced these? There is one website by a Guy named Scott that says he is building these but he never writes me back when I email. Not much else on the web.

[Steve Schell]

Tom, you beat me to it.

Dylanl, as I recall the 820A used the aluminum H-808 eight cell, 800Hz. aluminum horn with an 802B driver on top. Later versions of the 820 used the H-811 or 811A horn and probably 802C driver.

The demonstration of a pair of 820Cs at the home of an ex-Altec employee was my introduction to "the good stuff" about 20 years ago. They really blew my mind, as I had no idea at the time that speakers could sound that good.

[Steve Schell]

Dylanl, I think the pair in your picture are 820A systems, as they have the H-808 horns. I believe the cabinets are the 821A described in the brochure you posted, with front grills removed.

[Dylanl]

SO they always had that divider? I dont know these just look a little different. Any other clarification or know where I can get working plans?

[Dylanl]

The other side of the brochure looks a little different also, See they show no seperation??

[Steve Schell]

Dylanl, do you mean the horizontal board separating the two woofers? I think they all had that. Whoever did that drawing probably didn't have a picture of the cabinet with the grille removed, as the artist seems fairly clueless. It reminds me of the drawing of John Hilliard's home system in the book by Badmaieff and Davis, where the artist apparently had nothing to go on and drew the 802 high frequency driver as square!

These 820 cabinets are really striking in person. They are large and look even larger. They are graceful and elegant at the same time, with fine features and proportion. Altec never had many beautiful cabinets like JBL did, but someone did a nice job on the 820.

[Dylanl]

I think you are right here is a shot from the back.

[Steve Schell]

I have an Altec price list from October 1, 1952. The complete 820A system listed at $525. The 821A cabinet by itself was $285., and a version of the cabinet described as "frame only" was $99. The latter was probably for built in installations.

[Dylanl]

So as a DIY on this project the only thing I have to go with is what I already have?

If so would there be a better LF driver to use than the ones described?

[louped garouv]

should be able to use any of the ALtec woofs, right?

just make sure the mounting holes line up with the ones on the woofer frame.....


I am partial to 515Bs, but they are expensive lately from what I have seen sell....

I got lucky, traded up to the ones I have from a single 2225H :)



in my home now, I have a pair of 816A cabinets "stacked" on top of a pair of 825 clone cabinets; topped with 802Gs on a 511B horn....

I am guessing that a system like this would be pretty simmilar? maybe appearance of less low end due to losing the rephlex/ports portion of the 825/816a box?

sure as hell looks alot nicer....

[Tom Brennan]

Why do you want to build those anyway Dylan? I'm a'thinkin' they would have pretty bad bass, perhaps even worse than LaScalas.

They do look nice but I don't think they'd perform very well, especially on a size to f3 basis.

With some big subs, yeah.

[Dylanl]

I was thinking just the opposite. I thought this design would have superior bass. I am looking to build a no compromise horn set up full range. I want something better than the Khorns I have. Bass and midrange are the most important.

I really have no clue how these would sound but with 2 ~15" woofers you would think the bass should be good. But you may be right these may fall like a brick under 40 hz.

[Tom Brennan]

Dylan---I don't think they'll get anywhere near 40, the book says an 80hz cutoff. Those are awfully short horns and don't seem to have the bass reflex augmentation of VOT boxes.

On the other hand the corner placement may help. I dunno. I reckon if you build them you'll find out.

Might be worthwhile doing a fiberboard mockup of half of one, one 15, sitting it in a corner and see how low it goes. It should be pretty easy to just make a quick and dirty flare and rear chamber.

[speakerdave]

As I recall Davis et. al. said that horn loads down to 80 Hz, but with the boundary reinforcement of corner placement and the radiating surface of those two fifteens to engage room rise, I believe you would get adequate bass for listening to music in many situations.

David

[moldyoldy]

Since the horn's pretty much an 817 horn (or vice versa) less the reflex area, it wouldn't be much of a stretch to merge both designs, with vents in place of the 820's unsightly end caps, but still in a furniture-grade corner cab. If there's enough Vb left (>7cu/ft), a pair of 416s should feel right at home....

[Dylanl]

So what would that bass cabinet produce in Hz? I want something that will get down to 30hz flat lower if possible and have a sweet midrange. A 511 or other horn should be able to handle the top section.
I don't think that this should be that hard to design I just dont know what design would be the best candidate.

I looked at two other designs the Tannoy Autograph ( Folded Horn ) & the Jensen Imperial.

[Dylanl]

The imperial has great bass extension. It's big though and not wife friendly at all.

[Dylanl]

The Tannoy has a huge following and great reviews but its a very complicated build.

[Tom Brennan]

I think you should use big subs. The 820 cabinet would be most useful to give the glorious upper bass and midrange of Altec woofers in VOT type horns.

You could take them for that and then plumb low with some big dynamic subs based on multiple 15s or 18s.

I used a pair of JBL 4648s to augment some A5s I had below 100hz. With wall placement and 6db of boost at 30hz they were flat to 25hz in my room.

Yeah, I know you shouldn't EQ vented speakers but it worked.

[Dylanl]

Sorry one more note: I want true two channel ( no subs ). So I know it will take a special speaker to fill these needs.

Suggestions?

[Zilch]

Sorry one more note: I want true two channel ( no subs ). So I know it will take a special speaker to fill these needs.

Suggestions?http://audioheritage.org/vbulletin/showthread.php?t=13538

[louped garouv]

to augment some A5s I had below 100hz.

so, A5 = 515B and 1.4" Altec?

Is that an Edgar Horn?

and were you tuning the 825 cabinet's port in that picture?

[Tom Brennan]

Loup----That's a 515B in an 825. At the time of the photo I was using 2420s on Edgar saladbowls. At other tines I used various top ends including 288Ks on tar-filled 1005s, that's a proper A5.

[Dylanl]

http://audioheritage.org/vbulletin/showthread.php?t=13538

So was there a design that I missed in that thread. I saw talk of drivers but nothing else?:blink:

[Zilch]

So was there a design that I missed in that thread. I saw talk of drivers but nothing else?:blink:Five vented designs are given there via box sizes and tunings for five drivers....

[OLDGEN]

here is

[johnaec]

That should load nicely into the corner!

John

[Dylanl]

So what are your expectaions in HZ range?

[rghinton]

I am building 821's. You can see the project here. http://www.hostboard.com/cgi-bin/ultimatebb.cgi/ubb/get_topic/f/3729/t/2661

[OLDGEN]

he had asked me:barf:

[OLDGEN]

the second upload

[OLDGEN]

the third

[OLDGEN]

the fourth

[OLDGEN]

the last picture

[JBL 4645]

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=21962&stc=1&d=1168780069

OLDGEN

How do you get that nice (curved angle) on the vented horn system as don’t know anything about wood work?

[toddalin]

the second upload

Before I put my components (130A/LE175-HL-91/2402) into the L200 cabinets, they were in the University EN-15 cabinets (like the EN-12 shown but for a 15"). They sounded like cr-p with no real bass to speak of, even with all that twisting going on in the cabinet. The L200 cabinets were a vast improvement.

[AJSons]

More pics. Maybe they'll help.

[AJSons]

rear view.

[Surcouf]

Hello,

I own a pair of Altec Lansing speakers in excellent condition, which I believed to be vintage 820A. Checking a technical catalog on an internet site 'voiceofthetheatre.com'), I realized that overall height of my speakers is only 104,5 cm (41 + inches) and is smaller than 47 + indicated in the 820A catalog. Is it a variant of 820A ? Could it be instead a non genuine Altec Lansing manufacturing with those different dimensions ?

[music2me2]

I am building 821's. You can see the project here. http://www.hostboard.com/cgi-bin/ultimatebb.cgi/ubb/get_topic/f/3729/t/2661

I'm looking for any useful DIY info on the 821 cabinet - the project thread link above was a bit of a dead end, since all project picture links etc. weren't available any more.

If anybody on this forum, has pics, plans or useful links or tips, I'd be very grateful - THANKS!!!

Cheers
Peter

[music2me2]

Anybody...please?

[jcrobso]

Hello,

I own a pair of Altec Lansing speakers in excellent condition, which I believed to be vintage 820A. Checking a technical catalog on an internet site 'voiceofthetheatre.com'), I realized that overall height of my speakers is only 104,5 cm (41 + inches) and is smaller than 47 + indicated in the 820A catalog. Is it a variant of 820A ? Could it be instead a non genuine Altec Lansing manufacturing with those different dimensions ?

Altec made a mini variation of the VOTT for portable sound, I forget the model number. The problem has always been how get good bass from the speaker.
Most of the designs in this thread are from the 1950~early 1960s, They were in the first book I bought on speaker design. How do you get a big horn into a small space, the "K" horn was the best over all comprise, remember most everything is a comprise.:(

FYI, check here.
http://www.lansingheritage.org/html/altec/plans/1970s-plans.htm

[Steve Schell]

Check page one of this thread. Tom Brennan provided scans of the Altec plans for the 821A cabinet, as found in the Badmaieff/Davis book, which are the only ones I've seen. For further information you would have to find someone who owns an example of the cabinet.

[music2me2]

Thanks - this book is now its way to me :)

[speakerdave]

The question has been raised about the bass output of the (very attractive) Altec 821 corner cabinet. The horn cutoff is said to be 80 Hz. Boundary reinforcement and room gain would contribute at some point. One poster commented on the lack of BR as used in the VOT cabinets. But in post #40 one photo of an 820 system shows a distributed port exiting into the toe space. Anybody know any science about this? Looks like it might have been meant to be some kind of SOTP resistive loading. That space could be made a ducted port to tune the woofer cavity. What effect would the closeness of the floor have?