The Amperite Velocity Microphone
Continuing our review of Audio Engineering Magazine, today we will look at some of new offerings in microphones available to audio engineers in the late 1940s.
The Electrovoice 635
The Electrovoice 650 and 645. I really would like a nice 650… the ‘Jac Holzman Mic’
An Electrovoice line-up circa ’47
The Electrovoice Cardyne and Cardax
The Electrovoice Century
The Electrovoice V1 ribbon mic.
Many more images follow. Click the link below to Read-On…
Today we’ll look at some of the more interesting covers of Audio Engineering magazine from the first two years of publication. As incredible and exotic as these interiors are, consider for a moment how similar they are in content to the cover of today’s Mix Magazine. Get ready to enter a lost world of steel+glass….
Before audio engineers had a wide range of electronic equipment available to them (thanks to the introduction of the transistor), there was a tremendous emphasis on truly radical acoustic treatment and acoustic control devices. Although some of the brighter minds in audio continue to achieve radical innovation in acoustics (i’m remembering sitting in Blackbird Studio C a few years ago and being totally blown away), we’ve largely abandoned complex acoustic experimentation because… well… it’s a lot cheaper and easier to buy machine made hardware/code written by outsourced programmers. In the 1940s, you might have found that your cheapest way to improve hi-frequency response was to re-treat your entire room. Now we might buy just buy another mic. Or hang some pre-fab acoustic-treatment devices.
Follow the link below to see more..
Over the next few days, we’ll be taking a look at the latest-and-greatest in pro audio circa 194_, courtesy Audio Engineering magazine. In a previous post, we looked at Audio magazine, the venerable publication which advised legions of hi-fi enthusiasts between 1954 and 2000. As we discussed then, Audio was published as Audio Engineering for the 7 years prior, 1947 though 1953. It was only the introduction of The Journal of the Audio Engineering Society that precipitated the name change.
The changes went well beyond the name, though. With the AES Journal in-play, Audio shifted its focus towards hi-fi and consumer audio. Audio Engineering had sort of split the difference between home-fi and pro audio.
I’ve selected what I felt were the most interesting and relevant bits from the first 24 issues of Audio Engineering and I will present them here as follows: a survey of covers; professional microphones of the 1940s; interesting pro audio equipment; schematics of worthy DIY audio projects; and Western Electric ads of the era.
BTW, pictured at the top of this page: CBS radio KNX broadcast control center; an Electrovoice INC microphone test chamber; and the dubbing/rebroadcast room of WENR Chicago. Deco-mania.
Have you ever been driving around and noticed one of these huge metal antennae towers erected beside a home?
These are Ham Radio towers. ‘Ham Radio’ is non-commercial, amateur radio-broadcasting activity which has carried on for nearly a century all over the planet. Although by definition both amateur and non-commercial, Ham Radio is regulated by the governments of the world (including the US) and a license is required in order to participate. The plus side of the this regulation is that, unlike, say, C.B. radios, Ham Radios can be incredibly powerful and experienced operators can (with the right equipment) directly contact other like-minded enthusiasts all over the world. This actually sounds a lot like something else we’re familiar with… oh right the internet.
So much can be said about this venerable institution, and I am not person to do the explaining. So why discuss it here? Well… most common of the signals sent with Ham Radio has always been the human voice; many Hams have, and still do, carry on the tradition of designing and building their own audio equipment; and the innovations sprung from this field have played an important role in the development of audio technologies that we all use today. The importance of the technical aspects of signal transmission/reception in the Ham community cannot be overstated; in fact, most of he conversations that go on using this technology are in fact concerning the signal quality itself. A direct consequence of this importance of signal integrity is that Radio Hams would often send physical postcards, in the actual mail, to those individuals with whom they had chatted with on-air. These postcards confirmed the technical operating parameters of the radio equipment in-place when the successful conversation took place. These are called QSL cards, and they are one of the most fascinating and exciting examples of vernacular graphic design that I am aware of. E. purchased a crate of several hundred at the flea market yesterday; they all date from around 1980-1987 and they are really idiosyncratic and beautiful. Here I will present some of my favorites:
Follow the link below to continue…
Download the four-page circa 1975 ‘Bozak Compact Speakers’ Catalog:
DOWNLOAD: BozakCompactSpks
Catalog contains photos and specs for the Bozak Rhapsody, Tempo II (Tempo 2), and Sonora speaker units.
Bozak is another important chapter in Connecticut audio history. The famous manufacturer of legendarily large home hi-fi speakers was based in Connecticut for the entirety of their 30-year heyday. Pennsylvania native Rudy Bozak set up shop in Stamford in 1951, later moving to South Norwalk and Darien, with operations in several other towns. Wikipedia has an excellent and thorough treatment of Bozak, the man, his myriad technical innovations, and the long history of the company. No need to re-tread those waters; I will add this though: growing up in Connecticut, enormous 225-lb Bozak Concert Grand loudspeakers were a memorable site in the homes of some of my friends; a room-dominating testament to the intensity of a largely lost culture of audiophiles.
The fact that we are fighting three (3) wars at the moment (don’t try to tell me that those ‘drone planes’ in Lybia don’t represent a direct military strike) has me inevitably reflecting on the truth that we, America, are a militaristic nation first and foremost. In a previous post, we learned about the place that the venerable Altec tube compressors played in cold-war ear civil defense warning systems, an important role that no doubt led to the relative bounty of these devices today. Which leads to an intriguing question: how does an audio-equipment manufacturer get involved in high-level government defense contracting? Seems like a bit of a stretch, even in our highly militarized society. I mean, I don’t expect that Digidesign is making data-mining apps for the CIA….although as I type this, I realize that I am likely naive in this regard.
Anyhow, I found an answer to the question of Altec’s prominence in military/civil defense within the pages of the slim volume depicted at Left. “TRADERS GRAPHIC” (h.f. “TG”) is a private-press investors-guide from 1960. The cover price on this hand-stapled 32pp volume is $5, which would be $38 today. TG is essentially a tip-sheet which alerts potential investors to publically-traded stocks which have ‘major growth potential.’ In January 1960, one stock which TG endorsed was Ling Electronics; and the primary reason given for this endorsement was Ling’s recent acquistion of Altec Electronics.
Nice use of the little star type-pieces as a paragraph break. Anyway, prior to their purchase of Altec, what was Ling involved with? Read below for the full details, but I can sum it up as: vibration testing of ICBM and other missile components, as well as (then-novel) closed-circuit television systems for retail spaces. I.E., video surveillance. Realizing this, it makes perfect sense that we would soon see Altec audio equipment in government-contracted defense applications. Which, again, accounts in part for all the old Altec equipment that we still use today. Kinda cringing as I type this, but this really is proof yet again that the industrial base of any society (in the case of America, military/defense) will always find a way to inform all other aspects of that society (in the case of us, dear readers, music recording and listening – The Arts). Follow the link below for the full text on Ling from “TG.”
Download the six-page color product sheet for the venerable AKG K-340 headphone of 1979:
DOWNLOAD: AKG_K340
The AKG K-340 (not to be confused with the modern AKG K 340 earbud) was AKG’s top of the line headphone of the 1980s. Introduced in 1979, the K-340 took the basic design of the classic K-240 (which was very sophisticated in and of itself) and added the additional complication of a separate Electrostatic driver and associated crossover network.
Wikiphonia has a detailed entry on these unusual headphones, so no need to re-tread those waters; the six-page document I post here is some new material for the web, though, AFAIK. Check it out… and if anyone uses these cans, LMK yr thoughts…
Click here for previous vintage AKG headphone coverage on PS dot com
Looking through some old Fender Guitar Catalogs, I came across this unusual entry.
Behold the Fender Acoustic-Electric as it appears in the Fender 1965 Catalog (see catalog cover at right). I have never come across any record of this instrument before, and yet there it is… photographed… so at least one of them was made.
The Acoustic-Electric is pretty clearly the ancestor of the Fender Coronado, Fender’s ill-fated Gibson ES-335 competitor. The Coronado was sold from 1966 through 1972. There are a few notable differences between the Coronado and the Acoustic-Electric tho – the pickup design, the tailpiece design, bridge style, and the knob/switch placement. We also see a dot-neck on a two-pickup instrument (Coronados had block inlays on the 2-pickup instruments and dot-necks with single pickups), as well as the classic Fender headstock shape rather than the soft lower bout of the Coronado headstock. Taken in total, these small changes seem to represent a deliberate attempt to make the Coronado a more ‘rock/pop’ instrument than the somewhat ‘classier,’ ‘jazzier’ Acoustic -Electric. This change in direction would seem to correspond neatly with Fender’s purchase by CBS. I have to wonder if the Acoustic-Electric represented the thinking of Fender’s old-guard, which lost influence once CBS took charge. Who knows. Anyway, has anyone ever come across a Fender Acoustic-Electric? Or were they all destroyed? Anyone?
Ah the classic Altec 436C compressor (see here for previous coverage on PS dot com).
Here’s a fresh high-res scan of the original product-sheet (2pp):
DOWNLOAD: Altec_436C
I built one of these some years ago and it really sounds great. I used UTC ouncer -series transformers. Don’t be fooled by the tiny size – these are very good units. In fact, Ouncers are used in the early Urei 1176 as well as UA-175 and 176 compressors.
You can see how super-simple the circuit is. Aside from using a conventional power-supply circuit (rather than the voltage doubler that the original unit uses), i built mine pretty much exactly the same as the schematic.
Now, if you look at the schem, you can see that there is no provision for an output control. This is a problem because these things add a lot (like 20 db or more) level to whatever you put into them if you have the input control high enough such that the unit is actually compressing. In the past I have gotten around this by using an outboard Daven H-pad attenuator that I mounted in a little box. This is not ideal for ergonomic reasons. Anyhow… while studying the (very similar) Gates Sta-Level schematic the other day, I was intrigued by the very simple, very inexpensive variable balanced output pad that the Sta-Level uses.
It’s like $5 of parts. Five 1/2 watt resistors and one pot. Based on information in the Sta-Level manual, adding this circuit after the output transformer of the 436C will provide a minimum 10db and a maximum 16db attenuation. Perfect. Now, it’s true that using this control will vary the effective output impedance of the unit slightly; but according to Gates, “This pad has been carefully tested to assure that the small impedance mismatch resulting from this range adjust-ment will not affect frequency response or other characteristics. ” And Gates was writing this back in the day when the Sat-Level would almost certainly be seeing a 600ohm load. Considering that nowadays it will more likely see a bridging load of 1500 – 10k ohms, I think it’s safe so say that this circuit should be (at least as) sonically-transparent (as a vacuum-tube vari-mu limiter can be).
Gonna dig up some matched 160 ohm resistors and give it a shot… more to come…
Disco-mania. Behold an early electronic drum meant to compliment your acoustic kit. The Synare 3. This caught my eye mainly due to the address of the maker – Stafford Springs, CT. Any former Star Instruments principals out there in our fair state? Drop us a line…
