John Hilliard's built-in 50-ton audio system

[GM]

"How To Build Speaker Enclosures"

Yeah, Altec gave me a near enough new 9th ed. copy when I visited in '72 on the way back from my job related meeting at 'our' then LA Cutler-Hammer Assembly Plant and on my way to Mexico City for their inaugural 1/24th scale pro slot racing series, 'tentative' F1 race that due to Pedro Rodriquez's death was cancelled, ditto my reservation $$ , so factoring in I didn't get to meet anyone with a name I recognized combined with various unpleasant experiences 'South of the Border', a mixed blessing of my three week, somewhat company assisted, 'vacation'.

[joyspring]

Sorry to hear that your holiday was a disappointment but the factory visit must have compensated a bit.

And speaking of books, I visited a few times in the late 1970s / early 1980s and once received a photostat of 'Loudspeaker Enclosures: Their Design And Use' from the mid-1970s. It's a short, simplified enclosure guide with matched impedance peak port tuning. Also pre-Thiele-Small, like the Badmaieff / Davis book.

Here's a copy at the Lansing Heritage site:

1974 Enclosure Manual

~bob

[GM]

For sure! didn't mean to minimize it. Not really pre T/S per se, just not widely known to DIYers until the '81 Margolis/Small HP calculator program whereas my '74 Lotus?, later Excel, spreadsheets were done by one of the EEs I worked with thanks to one of the local Altec distributor designers keeping me 'in the loop' so to speak.

[joyspring]

Richard Small's AES papers spanned 1972-1974 and as a retired Altec/Cetec/Harman engineer once related to me, it took many years for old-timers to adopt these electroacoustic models. With a laugh, he mentioned that some never did.

I used Small / Margolis' HP RPN programs initially on a HP-97 and then a HP-41CX until I wrote my own in FORTRAN during university. The wide array of excellent software available today and the fact that component manufacturers publish complete and comprehensive specs make system design much simpler to say the least.

I still have my HP-97 on my desk on mains power but my 41CX has long been retired. I've had HP-11C, HP-32SII, HP-42S at various points in school and work but now use the open source (GNU GPLv2) Free42 on my Android-based mobile phone. I will admit I've been thinking about the SwissMicros 42S and 41CX clones (DM42 and DM41X) for nostalgia's sake. Long live RPN!

~bob