Category: Altec

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Altec

Helping you come to terms with the possibility of imminent demise

Download the 1965 and 1968 Altec ‘Airport Sound Systems’ brochures:

DOWNLOAD 1965:Altec_Jet_age_sound_systems_1965

DOWNLOAD 1968: Altec_airport_sound_systems_196X

What purpose can programmed sound serve in our environment?  Communication of information.  Entertainment.  Marking boundaries of different spaces.  All of this happens in the environment of an airport.  We need to know if there has been a gate-change for our flight.  We enjoy some sort of distraction or amusement while we wait.  We expect one sort of sound in the airport bar, and another at the gate.  OK.  So…  inform, entertain, delineate.  But how about… changing the mental state of an unsuspecting listener by lulling them into an acceptance of their relative insignificance in the universe in order to help assuage their fears of possible imminent death?

(web source)

Here’s how Brian Eno, composer of ‘Music for airports,’ widely considered to be the first ‘ambient music’ album, explains his project:

“… Whenever you go into an airport or an airplane, they always play this very happy music, which is sort of saying: ‘You’re not going to die, there’s not going to be an accident, don’t worry!’ And, I thought, that was really the wrong way around, I thought that it would be much better to have music that said: ‘Well, if you die, it doesn’t really matter.’ You know. So I wanted to create a different feeling, that you were sort of suspended in the Universe and your life or death wasn’t so important. …” (source)

Talk about turning the problem on-its-head.  I should say at this point that I am an unabashed huge fan of Brian Eno; IMO, there is no one person in the history of recorded sound that has been as able to imagine and exercise new potentials for audio.  Anyhow…  if you feel that his statements in the interview above seem somewhat grandiose/flakey/pie-in-the-(or falling from the)-sky-ish, I offer this personal anecdote.  I recently played the opening of  ‘music for airports’ for my students in my Soundtrack class (‘The Soundtrack’ is a course I’ve been teaching at the University which gives visual arts and communications students an understanding of the creative potentials of audio in their work).   We were discussing the programming of audio in public spaces – shops, restaurants, etc.  I played 5:00 of “Music for Airports” and asked what they music made them think of.  Several immediately responded, ‘death.’ OK, I replied…  how do you feel about this death?’  “Okay” was the reply.  Well done Eno.

It’s kind of hard to believe that there were so many airports in the US in the late 1960s that Altec published these 6pp and 8pp catalogs.   While there are no claims in these publications that these Altec systems might be used to effectively assuage customers’ fear of death, they do offer the following:

“Lack of reliability (in an airport sound system) can cause not only inconvenience but actual danger and panic in some cases.  This is why Altec Lansing, pioneer in integrated sound systems, has stressed aerospace-level reliability in every… component.”

Altec stresses here that lack of reliability, such as it might result in the mis-cue of important verbal flight information, can potentially cause danger and panic.   Eno took this one step further by understanding that the music-programming of the environment can also have a dramatic effect on the mental state of the customers; and he systematically set out to design sound-pieces that maximize the potential of the sound-system to comfort those customers.

Products discussed include the Altec 650, 687, and 695 microphones; various compressors and power amps; and audio-signal distribution equipment. ‘Case studies’ which catalog various successful Altec airport sound-systems already in use are provided as well.

 

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Altec

Takin’ em to Church (with Altec)

Download the eight-page 1966 brochure “Altec Sound Systems for Houses of Worship”:

DOWNLOAD: Altec_Worship_1966

The text above is taken from page 2 of this royal-purple-colored document.  The logical inference would be “As You Are To God, Your PA System Can Be To You! (with ALTEC)”

Been thinking about the voice/sound of God lately.  Our recent purchase of a massive Hammond Organ/Leslie speaker system at Gold Coast Recorders has led me to consider the features/tones/visual considerations that Hammond’s designers implemented when they designed these incredibly complex electro-acoustical devices.   The large Hammond Organs of the 1950s were designed (and commercially successfully, I might add) to replace the pipe organs which had functioned as a sonic {analog/representation/index/or-what-have-you} for religious expression in the Christian church for hundreds of years.  Notice that I say sonic  representation, as opposed to musical representation.  We experience the Hammond Organ/Leslie system as being impressive and one-could-say ‘godlike’ in it’s sonic attributes, even aside from any particular piece of music that’s performed on it.  The unusually deep, pure bass tones of the footpedals; the cavernous Hammond spring reverb system; the swells of the footpedal; the visceral emotional response that the Leslie speaker creates by way of it’s manipulation of the Doppler effect.

Sound systems in churches face certain special design requirements; this 1966 brochure from Altec addresses some of these concerns.  Low distortion, extremely high speech intelligibility, uniform coverage, and minimal visual presence; and all of this must be accomplished at a moderate overall acoustical volume.  Combine these sonic requirements with the fact that the sound system will often be operated by church members, ie., volunteers, ie., not-professional engineers, and you will find that operational simplicity is also necessary.

Given the large number of old Altec mixers on eBay with a stated provenance of ‘from an old church,’ I feel like Altec was probably pretty successful in their church-marketing initiatives of the 1960s.  From what I can gather, Peavey seems to be a leader in church audio today.  It’s interesting to examine the various products in their Sanctuary Series and note the differences between these and their standard nightclub PA line.

To my readers out there:  do any of you operate sound systems in churches?  Are there any special techniques in mic’ing, mixing, or processing of audio in the church environment?  Does anyone attend a church that is still using old green Altec PA kit of the 60’s?

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Altec Custom Fabrication

Altec 438A – Modified for modern music production use

As we discussed in previous posts, the Altec 438A is an audio compressor designed in the late 1950s primarily for use in public-address sound systems.  It has a microphone pre-amp built in, and an absolute minimum of controls:  one knob determines the level of the signal that hits the input of the compressor; turn this knob all the way down and you hear silence; turn it high enough and you get a highly-amplified version of the input signal; keep turning it up and you get a highly amplified signal with the peaks attenuated or ‘compressed.’  There is also a 2nd input with slightly less gain; this unbalanced 100k ohm nominal input shares the same volume pot as the mic preamp.  I suppose that the 438A was useful enough in its day, as there are hundreds still to be found; but for use in a modern music-production environment, it’s pretty useless.  The levels are all wrong, there is not enough control of the compression parameters, and there is no proper balanced line-level input.

Here is how I took an original-spec 438A and modify it so that one could use it alongside more modern compressors in a music-production studio.

(From Left to Right): A switch to determine if either the two-stage mic preamp OR a balanced 15K nominal signal hits the input transformer of the compression amp; a threshold/ratio combo control ala the later Altec 436C; (top) an balanced output level control/pad ala the Gates Sta-Level (see here for details); (bottom) a release time control ala the Altec 436C.  The original volume pot still functions as an interstage gain control for the mic preamp.

Here’s the unit with the face flipped down, revealing the wiring to the newly added pots and switches.  At my client’s request I used 11-position detented pots; ALPHA makes these in a huge range of values and Mouser stocks them for just about $2 a piece.  A great value IMO.  I used sliver-plated 24ga stranded wire for the audio wiring and 22ga solid copper for the control signal wiring.

This 438A is now ready for use in any situation where a gentle, vintage compression sound is desired.  The input and output levels are what you would expect from a standard pro-audio compressor; the release timing is widely variable (but never very fast – this would cause some artifacts due to the way these simple vari-mu compressors function); and the threshold/ratio control will yield a wide range of results as well.  Since the unit was in good physical and electrical shape, no re-tubing or re-capping was necessary.

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Altec Custom Fabrication Technical

Altec 436 Compressor: Taming the output level: part 2

In a previous post, we looked at the Altec 436 vari-mu tube compressor.  I built one of these a few years ago, and it never really got used all that much because the output level is so hot.  The 436 is a very primitive compressor design, and it sounds awesome- but it was also built primarily for service is installed sound systems: industrial paging use, etc.  The stock 436 circuit adds a lot of level to your signal if you have the input level set high enough to actually cause significant compression.  I built an external attenuator box using a 600-ohm Daven T-pad attenuator and a UTC transformer to re-balance the signal, but this was not really an ideal solution.  The box was pretty big and heavy and I generally could not be bothered with taking it out and setting it up.

The solution came to me when I was examining the circuit of the Gates sta-level.   Here’s the schematic if you want to take a look.   Now, this may look a lot different than the Altec 436 schematic, but the differences are not too significant – other than the fact that the gates has a regulated power supply, the circuits function in the same way; the main difference is the particular types of tubes that are used.  Both are fully-balanced vari-mu compressors which are staged as (input transfo)-(attenuator pot)-(vari mu input amp)-(driver stage in Gates only)-(output amp)-(output signal rectified, timed,  and sent to grid of input stage to regulate input stage amplification)- (output transfo).

The Sta-level, however, has an output level control, whereas the Altc 436 does not.  So how do they implement this?

Pretty simply.  5 resistors and a normal linear taper pot give us an output loss that we can vary between 10 and 16db, while still maintaining a safe operating impedance.  In all fairness: the BEST way to do this would be to use a balanced H-pad variable attenuator, which would give us the ability to vary the output from NO loss to, say 20db or so; but balanced H-attenuators are crazy expensive and very large physically; too large to fit inside an altec 436 chassis, certainly.   Another option would be to use a variable T-pad after the output transformer, and then add an additional 600/600 transformer after the T-pad in order to re-balance the signal (there is a certain vintage vari-mu compressor that works this way, but i can’t seem to recall which; anyone?).  This solution is also not ideal from a cost and size perspective, although it would certainly be less expensive than the balanced H attenuator.

Anyhow, the major downsides to the ‘Gates-solution’ are: 10db loss is inevitable; output impedance will vary slightly with use of control; variation range is limited to 6 db span.  Well; i used my output modded 436 in a session yesterday, and for what its worth, here’s what I can tell you:  the minimum 10db loss is welcome – it put the 436 into the same basic operating range as my 1176 and Distressor; the impedance mismatch (into a Lynx Aurora) did not cause any audible problems that i could detect when used on guitars and drum machines; and the 6db control range was fine as well – i was dialing in levels and getting sounds into Pro Tools with no fuss.

****

Before I drilled a fresh hole into the face of my 436 clone, I built the intended circuit into a tiny outboard box.  When the design confirmed itself, I added the circuit into the 436 itself.  But about this little test-circuit box:  it’s lightweight enough that it can simply hang off the patchbay, supported by the patch cables themselves.  Now every vintage mic preamp that I have can be given variable output control quickly and easily.  This will allow me to dial in extra-gritty sounds using the preamp gain control (which is generally interstage rather than input or output), and then use this little device to get the level back down to an appropriate level to hit the convertor.

If you own a vintage Altec 436 or 438 and you find that you have to battle the high output level, I highly suggest that you give this modification a shot.  It’s very easy to simply build it into an outboard project box at first in order to see how you like it before you drill a hole in yr Altec.  And if you use any vintage tube gear in the studio: try making one of the little boxed-versions of the circuit.  It will really open up some new creative and sonic possibilities for the gear you already have.

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Altec Pro Audio Archive

Pro Audio hardware of the early 1950s

The General Electric (GE) BA-5-A Limiter

Continuing our review of the first two years of AUDIO magazine, today we will look at some of the more interesting bits of pro audio kit in evidence during 1954/1955.  AUDIO magazine had just made the transition to its new moniker in the wake of the introduction of the AES Journal (Audio Engineering Society), and for the moment, AUDIO sill covered a bit of the pro audio equipment that would soon largely leave its pages.

The GE BA-5 pictured above is, AFAIK, the largest and most complicated analog audio compressor ever made.  Although it has much less tubes, it’s kinda even more sophisticated than the Fairchild 660/670.    Here’s the schematic if you are interested.  From what i recall,  the BA-5 works by creating an ultra high frequency sidechain to obtain the control voltage value for the compression; I can’t recall the details at the moment but the basic concept was to allow the unit to have huge amounts of compression with very fast timings, but without any pumping or dipping artifacts.  Which was also the intent of the 660/670 design.  If anyone out there has a better explanation of this monster, please chime in.

The General Electric BA-6-B remote amplifer/mixer

The General Electric BA-9-A compressor, a much more basic pro audio compressor.  Circuit is essentially the same as the Gates Sta-Level.  The BA-9 is also known as the the uni-level; schematics are readily available online.

The General Electric BA-1-F plug-in preamp and BA-12-C plug-in power amp

The Hycor 4201 equalizer.  Similar to a Pultec program EQ but without the makeup gain amp; the Hycor is a fully passive device.

Langevin 5116 modular preamp

The full Langevin modular line of 1954: 5116 preamp, 5117 power amp, and 5206, 5208 power supplies

Another remote amp from 1954 – the Magnasync G-924.  Looks very cool.  Magnasync would soon be merged with the Moviola corporation and become a brand name for sound-for-film equipment.  See this previous post for an experiment with the Magnsync URS device.

An early ad (1955) for the Altec 604 duplex loudspeaker.  The 604 would remain a studio-standard recording/mixing monitor speaker well into the 1970s.

Okay this is getting pretty tech-y but here’s an advert announcing some new-ish tubes you might want to consider: the Tung-sol 12AX7 and the 5881 (AKA ruggedized 6L6).   Transistors were on the market at this point (1955) but were a ways off from reaching the performance and reliability that these great tubes offered.

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Altec

Missile Testing, The Dawn of Video Surveillance, and Your Speakers

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.”

Continue reading “Missile Testing, The Dawn of Video Surveillance, and Your Speakers”
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Altec Technical

Altec 436 Compressor: Taming the Output Level

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…

 

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Altec Pro Audio Archive

Altec Sound Equipment 1968

Download the sixteen-page 1968 Altec Sound And Communication catalog:

DOWNLOAD:AltecFullLine1968

Products covered, with text photos, and limited specs, include the full range of microphones, horn speakers, Duplex coaxial speakers, full range drivers, voice-of-the-theatre systems, tube and solid-state power amps, pre-amps, compressors, and mixers; the full range of plug-in transformers, 9200 console and attendant components; a page devoted o the ‘Giant Voice’ public warning system (see earlier post); plus the range of telephone audio equipment and intercom systems for industry and hospitals.

If you are not familiar with Altec’s classic pieces, this brief catalog is a great place to start.    Altec’s market-leadership would soon be supplanted by a range of innovations introduced by smaller companies in the 1970s, but at the time, this was still top-end gear.  Much of this equipment is still used today; if not in recording studios, then by audiophiles.  Dig in.

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Altec Concert Sound Microphones Pro Audio Archive

Altec Musical Sound Equipment circa 1973

Download the sixteen-page Altec Musical Sound Equipment catalog circa 1973:

DOWNLOAD: AltecMusical1973

Products covered, in text, specs, and lovely 70s gradient photography, include: Altec 417, 418, 421, and 425 series musical instrument speakers (drivers); Altec 626A, 654A, 655A, 650B, and 656A microphones; 1212A and 1214A ‘altec control consoles’ aka powered mixers; 1207C, 1211A, and 1217A column loudspeakers; 1202B, 1204B, 1208B, and 1218A ‘voice of the theatre’ speaker systems; 771B BiAmplifier and its associated 1209B, 1219A, and 1205B powered ‘voice of the theatre’ systems; 1215A an 1225A folded horn and multicell tweeter; 9477B power amplifier; 1220AC ‘audio control console’ aka 10×1 live sound mixer; plus the contemporary voice of the theatre individual components 811B and 511B horns, 807-8A and 808-8A drivers, N809-8A crossover, and 828B cabinet.  Plus a range of accessories.

This is not a full-range catalog; rather the focus is plainly on live-sound reinforcement for rock and pop bands.  There is an emphasis on volume, power, and road-worthiness in all of the product-prose.

Dig the excellent tequila-sunrise comin’ on behind the Altec Musical Instrument Speakers.  It was a popular, if pricey, move in the 70s to replace the factory-installed drivers in your Fender Amp with an Altec (or JBL) aftermarket speaker.  Many amplifier manufacturers of the era offered these as factory-installed options as well.  I have never liked the sound of of these speakers in a guitar amp.  It’s likely simply because I have a more roots-oriented guitar style, but i find that Altec and JBL speakers really rob a good tube amp of the responsiveness (touch-sensitivity) and proper harmonic-breakup that I depend on from the amp.  Maybe if you are into Jazz and/or Metal these would be a good choice.  Anyhow, I always replace them with regular Alnico or ceramic instrument speakers, which generally have a more limited frequency response.  Another downside of the JBL replacement speakers in particular is that they weigh a goddman ton, turining your Deluxe Reverb into something requiring casters.

Since this is essentially a live-sound catalog, the microphones on offer are limited to a range of 5 hand-held type units.  The top-of-the-line dynamic on offer is the 654A.  I bought pile of 4 of these on eBay a few years ago when I needed some mics for a series of rehearsals we were doing.  They were pretty cheap and I figured they would work pretty well.  I found them to be not especially durable, but decently so.  They have pretty good sound, but the feedback rejection is really really bad, even with properly-positioned monitor wedges; but perhaps their worst feature is that the shafts are so frikkin thin that you need to use those awful spring-loaded mic clips.  We still use these in the rehearsal studio when absolutely necessary, but I cannot recommend them.  Might sound cool on acoustic guitar for recording applications.

If you have been following this website for a while, you will know that I am totally obsessed with this style of product photography.  Bring that shit back I say!

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Altec Pro Audio Archive

Altec Professional Audio Controls Paper Circa 1960’s

Around the time that ALTEC introduced their 947X series of solid-state plug-in amplifiers, ALTEC staff engineers Arthur Davis and Don Davis published the following paper in AUDIO magazine (see my previous post on AUDIO mag).  ALTEC then reproduced and re-printed the paper as promotional material. I have scanned and uploaded the fill 12-page document.

DOWNLOAD: Altec_Professional_Audio_Controls

Covered in this document: the 9200 modular console, the 9704A transmission measurement set, and the various ALTEC passive equalizer units of the period: graphic, shelving, and pass filters.

Check out the publication.  It is a good quick primer on early impedance-matched mixing systems.  In the future, I will post more extensive documentation on these ALTEC consoles and filters.