Altec 820 DIY musings [from DIYaudio.com]

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Help identifying Altec cabinet/model/plans - diyAudio

Long time listener, first time caller...

I've been looking to start an Altec project.


These cabinets have really gotten my attention.


They claim they're 820's, but the only info on 820's I can find is about corner loaded 821 or 820a/c. Those were driven with 2x803 for LF and 802/H808 for HF. Nothing about this style cabinet. They say the dimensions are Cabinet Dimension(each): 29 3/4" x 23 3/4" x 48"(inches), and the ~24" depth is very appealing to me.


Anyway, I'm looking for any info on these as I'd consider building a pair if I had more to go off of. Maybe this cabinet could benefit from reflex porting like the 817? Has anyone seen cabinets like this? Or similar plans?


If any of you are familiar with these, would you search for 803LF drivers? Would 416s or 515s "work"?


Thanks!
z


Here are the photos from the ad

Plans begin on pg. 96:

How To Build Speaker Enclosures By Alexix Badmaieff & Don Davis : Free Download, Borrow, and Streaming : Internet Archive


This speaker project is best served on the Altec User's Board [AUB] where there are owners, so see you there!

https://www.hostboard.com/forums/f70...ers-board.html


Correct re drivers, though the original used the superior performing, and fairly rare Lansing 800 Hz 808 multi-cell.


FWIW, yes, a little bit familiar with Altec in general and the 820 in that it was part of my DIY speaker, horn design education, DIYing an [improved] stereo pair of A7-500.

In a 'nutshell', these were designed for 16 ohm high output impedance systems, so unless Great Plains Audio [GPA] can make some ~replicas performance wise, best to use GPA's $ AlNiCo $ 416B series for closest performance, though its ferrite 416-8C can be EQ'd to get the desired response, just not the AlNiCo's 'sweetness'.

The 811 horn is still around used at reasonable prices and recommend the GPA 802-8G drivers that are superior to the originals.

Might can find the original XOs used, though can only recommend the early ones [assuming 16 ohm] as the later ones are just basic 8 ohm 2nd order Butterworth IIRC.

Older 515s make less bass, even 'sweeter' mids/HF, so owning 515Bs, it's what I'd use [or GPA's ~equivalent 515C] and EQ to suit.

It has reflex porting out the back/bottom, venting out the bottom/front.