I've been a fan of the original Altec A7 "Voice of the Thetre" loudspeakers since childhood. I grew up with a set of Altec 846Bs in the living room and over the years have owned both A7 VOTT's and Model 19 Studio Monitors. I don't think any of these really compete with the more modern projects DIY speaker builders can build today like dipoles and CBT arrays but considering the A7 was designed in the 1940's, well before Thiele/Small, I think they're pretty good.
For you kids out there with "Altec Lansing" PC speakers, what you really have are "Spark-o-matic" speakers. In the late 1970's to early 1980's Spark-o-matic made a lot of cheap car audio speakers and while they were actually pretty good for the price the name quickly became synonyms with "cheap audio". Around 1986 they bought the rights to the name Altec Lansing for consumer products and for commercial products when the real Altec closed around 2000. Altec Lansing was a pioneer in audio making most of the commercial cinema speakers from the 1930's through the 1980's. The PC speakers today baring the name "Altec Lansing" have no similarity with the real Altec
Some years ago I made a number of e-bay purchases of Altec hardware after which my brother Marshall and I built three sets of A7 cabinets. One set belongs to a friend, another set is suspended in the Audio Artistry shop for background music, and my set is currently stored.
Some original construction photos from my original web site...
These cabinets are based on various Altec drawings from the early 825 cabinets to the later versions of the 828 cabinet. Like the 825, only the upper section of the rear panel is removable. We figured keeping the lower section rigidly mounted would give the cabinets more strength. Also, we added an additional brace in the bass horn section to make the 1/4" plywood more rigid.
My brother Marshall has redrawn the A7 original plans for better clarification and readability. You can download the PDF document here and the horn flare PDF here.
12/5/2020: Marshall has now drafted a drawing providing details on how to cut the complex curve for the horn flare. You can download that drawing here. This .pdf drawing is best when zoomed to 100%
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