I can't find the article but blame it on David Weems ;^) - - ~1971 = rather large t-lines - like 40"x24"x20" each. The plywood I purchased was not very good and had lots of voids.
Driver selection was kinda pin the tail on the donkey with a Lafayette branded 12" woofer, (probably feeble motor). an 8 inch whizzer cone speaker for the midrange and a 2"x5" or 2"x 6" metal horn tweeter. Later I went to Philips 5" mid and mylar dome. The crossover was an outboard unit by Lafayette.
They did get a fair amount of use with my Eico ST40 and 70 but weren't anywhere as good overall as say a KLH 17. I do remember the crappy plywood top flexing.
A Mello Monster would have been fun - and certainly the Karlson K15 with good coax.
Driver selection was kinda pin the tail on the donkey with a Lafayette branded 12" woofer, (probably feeble motor). an 8 inch whizzer cone speaker for the midrange and a 2"x5" or 2"x 6" metal horn tweeter. Later I went to Philips 5" mid and mylar dome. The crossover was an outboard unit by Lafayette.
They did get a fair amount of use with my Eico ST40 and 70 but weren't anywhere as good overall as say a KLH 17. I do remember the crappy plywood top flexing.
A Mello Monster would have been fun - and certainly the Karlson K15 with good coax.
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Mid-seventies, huh? And, quite specifically, we are in the multi-way loudspeaker forum.
Thiele/Small parameters were still new kids on the block, so I was building speakers for myself and others based on Wharfedale drivers and enclosure designs.
I started with a pair of Wharfedale's distributed port (DP) cabinets then graduated to calculating the dimensions of reflex ports using Gilbert Briggs' traditional tuning formula contained within his "Loudspeakers" book:
f² = (2700A) / V(L + 0.96√A)
where:
f = enclosure resonance frequency
A = area of vent or pipe in square inches
V = volume of cabinet in cubic feet
L = thickness of cabinet wall, or length of pipe, in inches.
Enclosure volumes ranged from 2 cu ft to 5 cu ft using 10" and 12" FR drivers (with helper horn tweeters), and some jolly good results were obtained!
Thiele/Small parameters were still new kids on the block, so I was building speakers for myself and others based on Wharfedale drivers and enclosure designs.
I started with a pair of Wharfedale's distributed port (DP) cabinets then graduated to calculating the dimensions of reflex ports using Gilbert Briggs' traditional tuning formula contained within his "Loudspeakers" book:
f² = (2700A) / V(L + 0.96√A)
where:
f = enclosure resonance frequency
A = area of vent or pipe in square inches
V = volume of cabinet in cubic feet
L = thickness of cabinet wall, or length of pipe, in inches.
Enclosure volumes ranged from 2 cu ft to 5 cu ft using 10" and 12" FR drivers (with helper horn tweeters), and some jolly good results were obtained!
The math in Weems books was great. You could calculate from driver specifications and dimensions with a pencil & paper, logarithms or a slide rule. No updating the op system of the computer or phone to cope with new revision software every 9 months. OTOH Weems projects were minimalist ****. They looked like those speakers that sounded so bad down at Radio Shack. The math works on 15"+CD horn speakers, which can be very good.
In 1970 I bought a used dynakit PAS2+ST70+AR turntable. I took a replacement 6x9 Quam driver for my car to listen to it with. Laid it on the dresser top. Terrible. Open baffle, Ha Ha. I cut two holes in a cardboard box, 6x9 in the front and 1x1 in the back. Sort of like the '59 ford dashboard the driver was bought for. MUCH better sound. That lasted until I bought a pair of LWEIII 2 ways in 72.
My good friend whose father was a ham radio op, built two 24"x30"x16" cabs with 4 of the best Allied Radio drivers (each) you could buy. Maybe Lafayette Radio catalog. We did not discuss any crossover components. I think the sound was worse than the 6x9's in the cardboard boxes.
In 1970 I bought a used dynakit PAS2+ST70+AR turntable. I took a replacement 6x9 Quam driver for my car to listen to it with. Laid it on the dresser top. Terrible. Open baffle, Ha Ha. I cut two holes in a cardboard box, 6x9 in the front and 1x1 in the back. Sort of like the '59 ford dashboard the driver was bought for. MUCH better sound. That lasted until I bought a pair of LWEIII 2 ways in 72.
My good friend whose father was a ham radio op, built two 24"x30"x16" cabs with 4 of the best Allied Radio drivers (each) you could buy. Maybe Lafayette Radio catalog. We did not discuss any crossover components. I think the sound was worse than the 6x9's in the cardboard boxes.
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Yes, Weems made the basic mathematics accessible while supplying helpful charts to simplify the design process.
However, my Radio Shack issue of Building Speaker Enclosures by David Weems also included "Caudle's Loudspeaker Design Program For Radio Shack TRS-80".
I typed that 8 page BASIC program into my computer of the day (a BBC Micro) and it served me well when I moved onwards from my Wharfedale days.
P.S. The above Weems book does not include freddi's design.
A set of home-brew coaxial boxes using Radio Shack drivers, didn't sound too good but it was my first go with speakers. And a pair of Southwest Technical Products "Tiger 0.1" amplifiers. Also a SWTP preamp, which was kind of a disaster, it had push-button tone controls that didn't work well and I think made it oscillate sometimes. 
.
I used an Eico 35W/channel amp after that, wish I still had that amp. Then built Built a set of SpeakerLab "K"s (their version of the Klipschorn). Never got the EQ and crossover right, had no way to measure (and that fiberglas midrange horn was just plain terrible anyway).
. I used an Eico 35W/channel amp after that, wish I still had that amp. Then built Built a set of SpeakerLab "K"s (their version of the Klipschorn). Never got the EQ and crossover right, had no way to measure (and that fiberglas midrange horn was just plain terrible anyway).
That's amazing. I have nothing from that era. I built probably 4 pairs in that era, all drivers from McGee Radio. I liked the Phillips stuff, AD1061 and had the 8" butyl woofers which I replaced in a subsequent design with Eminence 10" guitar speakers to take to college, where they served for 4 years, the sold to a roomate rather than haul back home.
During that time I made cabinets covered in wide-wale blue corduroy. I couldnt figure out how to stretch the stuff over the cabinet, so I turned one corner's edge into a clamp using a blind bolt, pulled it tight and clamped it down. There - fixed it!
I remember there was this nomograph in a Radio Electronics issue. Something about resonance into a standard box volume, a second resonance at free air. Gives the enclosure volume. Something else gave the port diameter and length. Having no test equipment at the time and knowing myself, I probably just guessed at it all...If I did use it as per the instructions, I cant remember doing the tests.
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I built a Z80 based CP/M computer with 64kx8 DRAM and video display. It took about a week to solder in all the ICs, another month to code an assembler in machine code, and a few more months to code the BIOS and BDOS in assmbly language. It was really good at generating RF hash, and would kill AM and some low band VHF over the air signals... I learned a lot though.
the first advertisement of Klipsch home audio speaker was 1947 (!!!) - go to
https://www.diyaudio.com/community/...kers-still-made-today-overview-wanted.403092/
https://alfred-lettmann.hpage.com/das-klipschorn.html
I know many of Klipsch's Eckhorn clones as diy project from the 80s - good known are the ones from the companies ACR (CH) and KLIMO - go to
http://home.datacomm.ch/nschroeder/Bauplane
Maybe one of the member know the first diy project of this loudspeaker approach in a magazine from the United States, maybe already released in a electronic magazine between 1950 and 1960 - thank you.
https://www.diyaudio.com/community/...kers-still-made-today-overview-wanted.403092/
https://alfred-lettmann.hpage.com/das-klipschorn.html
I know many of Klipsch's Eckhorn clones as diy project from the 80s - good known are the ones from the companies ACR (CH) and KLIMO - go to
http://home.datacomm.ch/nschroeder/Bauplane
Maybe one of the member know the first diy project of this loudspeaker approach in a magazine from the United States, maybe already released in a electronic magazine between 1950 and 1960 - thank you.
That was a time when I really could have used a mentor, someone who knew about sound. No one on my street even had a component stereo, except for Mr Esch a couple of houses down. He also had a PhD in physics. He had an HK receiver and KLH speakers. He let me hook up my little EV receiver one time, for the express purpose of I wanted to hear what "real" (commercial...) speakers sounded like. His only remark was toward my little receiver "seems pretty sensitive".
Beforehand the guy next door who repaired TVs on the side had given me the guts to a large GE console; a receiver chassis and an amp / powersupply connected via an umbilical. The phono input had lots of gain and a tube mounted on rubber isolators, which was very microphonic.
I used to impress my friends by burning up the VC of small TV speakers and the like, by connecting them to this 6V6 amp and turning the volume up all the way. I used to plug in other tubes in those sockets; one time I saw a 6L6 in a shouldered glass envelope flash bright white inside for some reason, probably during another speaker killing. The amp still worked afterward. I never did figure out what the second pair of 6V6s did in that amp design, all I could tell is they didnt connect to the OPT.
Beforehand the guy next door who repaired TVs on the side had given me the guts to a large GE console; a receiver chassis and an amp / powersupply connected via an umbilical. The phono input had lots of gain and a tube mounted on rubber isolators, which was very microphonic.
I used to impress my friends by burning up the VC of small TV speakers and the like, by connecting them to this 6V6 amp and turning the volume up all the way. I used to plug in other tubes in those sockets; one time I saw a 6L6 in a shouldered glass envelope flash bright white inside for some reason, probably during another speaker killing. The amp still worked afterward. I never did figure out what the second pair of 6V6s did in that amp design, all I could tell is they didnt connect to the OPT.
I too did a TL build using the KEF B139, B110, T27 & a Coles 'super' tweeter using Falcon crossovers. It followed the Bailey plan (yes, let me preempt any comments about that and say that I know Bailey was incorrect in his theories, but none of us knew that then, did we?) However, those were proceeded by a pair of Tannoy 12" Golds in bass reflex cabinets. Wish I'd kept the Tannoys.