Author: chris

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Out-of-print-book report: Magnetic Recording (1948)

Not sure where I came across this obscure volume.  Written by one S.J. Begun, then VP and chief engineer of recording-tech pioneer Brush Development Corp, ‘Magnetic Recording’ (h.f. ‘MR’) was completed in June 1948 and published the following year by Murray Hill Books.

There is a lot of information in this 235pp volume; the best feature by far, though, is that it contains diagrams and schematics for a great number of the recording devices discussed.

Here’s a quick survey of the machines covered in MR.  Most are wire recorders.  Remember that tape recording was still incredibly new in 1948; wire was still the dominant format.  If you have any of these machines and need to service it, seek out this book. You might find what you need.  Names are beneath each image.

The original circa 1948 Ampex tape recorder, which promised an unheralded 30-15k (+/- 1db) frequency response.

The WW11-era German Magnetophone, from which the Ampex was largely derived.  The Magnetophone ran at 30 ips in order to achieve its (then) excellent performance.

The Armour Master wire recorder.

The Armour Model 50 wire recorder

The Bell Labs Mirrorphone

Brush Labs Model BK-303

Brush labs model BK-403, the portable Sound Mirror

Brush Labs model BK-503 ‘mail a voice,’ which recorded a magnetic signal on coated paper discs.

Brush Labs SoundMirror

Brush Labs model BK-401

The Lear Dyanport (pictured with American Dynamic mic)

The Magnecorder SD-1, a predecessor (prototype?) of my beloved Magnecord PT6.

The Nemeth Master Wire Recorder

The Peirce Dictation model 55-b

The Rangertone, by Rangertone

The Telegraphone, a pre-vacuum-tube wire recorder.  See this earlier post for the details.

The Webster Wire Recorder.  In my experience, these are the most commonly-found wire recorders that you may encounter.

The WiRecorder Model PA

Categories
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.

Categories
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!

Categories
Antique Hi-Fi Archive Pro Audio Archive

Fostex RP Headphones 1977

Download a high-res scan of the four-page 1977 Fostex RP Headphones catalog:

DOWNLOAD: FostexHeadphones1977

Models covered, with specs and photos, are: Fostex T50, T30, T20, and T10 headphones.

On-the-go music-listening is more popular now than ever due to the convenience and features offered by devices such as the Apple iPod.  This new technology has also driven the demand for quality headphones.  When asked for headphone recommendations,  I generally steer people towards the Sony MDR-7506, due to their relative portability, extremely low impedance (translation: even an iPod can make them very loud) and very present sound.  Plus they have a 1/8th-inch jack, so they mate properly with your iPhone iPod or whathaveyou.

This all being said, I always also tell folks that I personally do not listen to music on the MDR-7506.  They are too hyped and unrealistic-sounding to me.  I am not sure exactly what they do to the sound, but they make everything sound ‘better’ in a way that i don’t really find ‘better’ but instead somewhat cloying.   Regardless, if you want headphones that will play loud, shut out the outside world, and last forever, the 7506 is a great bargain.  This is also why almost all musicians prefer the 7506 in a recording-studio-tracking situation.  I own several pairs for this reason.

What I use personally for monitoring in the studio is the Fostex T50RP.  When I am tracking I find the 7506 to be the best choice, but whenever I am behind the desk and need to monitor with headphones for one reason or another, I put on the T50s.  Likewise, they are good for music listening at home.  They give a good, accurate sound, and they are just so robust and well made.  These things really are the best value in audio today.

Turns out that the Fostex RP line goes all the way back to 1977.  The components have changed a couple of times over the years, but the basic printed-diaphragm technology which distinguishes the RP line from most other headphones has remained the same.

According to the excellent ‘Wikiphonia’ headphone web database, the RP line was originally introduced as a less-fussy (IE, no power supply needed) alternative to the then-novel and popular Stax Electrostatic headphone line.

Pictured above is the Fostex T20 as it first appeared in 1977.  The T20, like the T50, is still be manufactured today in a slightly varied form. The T20 seems to have undergone the least cosmetic change since its introduction.   I do not recommend the T20.  I have owned a few pairs and I find the very dull and chalky.  My advice: spend the extra 20 bucks and get the T50 instead.

Categories
Guitar Equipment Icons Pro Audio Archive

ICON: Kustom Instrument Amplifiers: 150, 250, 500 series

Download the twelve-page 1972 Kustom Electronics, INC catalog for their 150, 250, and 500-series guitar and bass amplifiers.

DOWNLOAD: Kustom_150_250_500_Catalog

Kustom amps, with their ‘tuck and roll’ sparkle-Naugahyde upholstery covering, are a true icon of the rocknroll amplifier.  Bud Ross took the idea of RocknRoll=hot rods to its logical conclusion with these things.

Tuck and Roll custom hot-rod upholstery (web source)

Interesting how well the Rock-Music/Hot-Rod connection worked in the 50s/early 60s.  Consider the Gibson Firebird and Fender Stratocaster guitars, both of which had direct aesthetic relations to youth-favored automotive designs of the times.  At right: the 1953 Buick Wildcat (source).  Below that, the Fender Stratocaster, designed in 1953 (source).

I wonder why no one has made a Honda Civic or Subaru WRX flavored guitar (or beat-making software interface WHOA maybe getting too far out there…)

The 1940 Chrysler Windsor, designed by Ray Dietrich (source)

The 1963 Gibson Firebird, also designed by Ray Dietrich (source)

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From Wikipedia:

“Rockabilly and Motown musicians originally used (Kustom) amps. Other artists known for using the Kustom brand for live applications are Creedence Clearwater Revival, The Altamonts, Dusty Murphy, 3 and Sheryl Crow. Some of the most famous Kustom P.A. users include Creedence Clearwater Revival, Leon Russell, Johnny Cash, Roy Clark, The Jackson 5, Carl Perkins,Alun Tan Lan(Y Niwl) and The Carpenters.”

All of the original 1960s and 70s Kustoms are solid-state amps, so their appeal nowadays is mainly for their cosmetic a(e)ffect.  These things were no slouches in the technical department, tho – the 250 and 500 lines shipped with optional JBL or Altec speakers (look for the silver dustcap on the drivers); furthermore, when you come across one of these things nowadays, they generally work well, which is more than can be said for most 40-year-old solid-state guitar amps.

Pictured above is a German 1972 pricelist for the entire Kustom line.  If there is enough demand I will scan and upload the entire thing.

(web source)

(Web Source)

A Kustom-Brand Police Radar gun.  Hot Rod Cars are still a focus here, but the situation has changed dramatically.  And yes the same man is responsible for both product lines.   (Web Source)

Since Kustoms are so iconic, there is a ton of information on the web regarding these artifacts and their very colorful and storied creator Bud Ross.   Ever wonder what the connection was between Kustom and Kasino?  And a gambling addiction? Promo branded halter-tops?  Unsavory-looking plush toys?  And police radar guns?  Yes folks it’s all true.  This is an American Epic.  Here’s my pick of the best:

History of Kustom/Kasino amps and Bud Ross

A great stockpile of vintage Kustom literature

Personal site of a Kustom super-collector

History of the various Kustom lines

Polymath Bud Ross on-camera delivering an oral history of Kustom and his later ventures

Categories
Pro Audio Archive

Lexicon Digital Audio Processors of the 1980s

Download twenty-one pages of original Lexicon catalogs and sales materials from the mid 1980s.

DOWNLOAD: LexiconProcessors1980s

Full details, photos, and specs on: Lexicon Model 97 Super Prime Time programmable digital delay; Prime Time II; PCM-42 delay unit; PCM-70 effects processor; 224-X Digital Reverb; plus a period price list and sales letter.

It’s hard to remember just how important these devices were back in the 80s and early 90s, before the advent of DAWs (e.g. Pro Tools) and the audio-processing plug-in effects that accompanied the DAW.  Sure, Lexicon digital reverb may not ‘really’ sound like the sound of a ‘real space,’ but it sure did sound like the sound of a Hit Record for a good long while.  And if you wanted That Sound, the only way to get it was with one of these devices.   There is still some demand for these devices (PCM-42s still go for around $1000 used), likely due to older engineers’ familiarity with these devices, as well as their still-relevant live sound and instrument-rig applications.  Interesting to read these specs and see that, at best, these were 16k bandwidth devices.   Who would dream of setting up a new Pro Tools session at 32K sampling rate these days?

Unfortunately I could not find any paper work on the most expensive item on the pricelist – the Lexicon 1200CMS stereo Digital Time Compressor/Expander.

(web source)

This was a truly significant, cultish device.  You can occasionally find them on eBay for around $200.    Cost new in 1985?  $15,995 for a stereo unit.  In today’s money, that’s  thirty-two thousand ($32,000) d0llars for a device that could (at 32k) pitch-shift a stereo program a semitone or so.

Who in their right mind would pay this money for this kind of functionality?  Broadcasters, primarily.  If you spend any time working in television post-production, you will still hear older producers and creative directors say “Lexicon it” to the sound engineer.  Now, when they say this, they are not telling the mixer to put a shit load of echo or reverb on the audio.  In the post-production audio world, “Lexicon-it” was an imperative to time-shift material.  As-in, “Hey, johnny read that tag line a little slow.  Can you Lexicon it, Joe?”  The vogue for these devices in Broadcast really took off when put-upon ad-agency types realized that you now could make a 32-second commercial, and then speed the spot up to play back in 30 seconds time whilst ‘Lexicon-ing’ the audio program back to regular pitch.  At the end of the day, the TV viewer can’t tell that anything is off, but you, Mr Crafty Agency dude, have managed to cram thirty-two seconds of your boss’s and clients’ revisions into a a thirty second commercial.  You are now a genius.  This is the stuff on which vacation homes are made.

Of course, music-recording engineers also used these things daily to fix pitch-y vocals and what not, but that’s a story for a different day…

Categories
Pro Audio Archive

Aphex Aural Exciter Lineup circa 1984

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Download 6 pages of Aphex Systems INC sales material circa 1984.  Details on the entire lineup, plus full specs on the Type B and Type C ‘Aural Exciters.’

DOWNLOAD: Aphex_exciter

Products covered, with specs and photos, include: Aphex II-S Exciter; Aphex II-B exciter; Type B and Type C exciter; Compellor Compressor; EQF-2 and CX-1 lunchbox cards; Aphex R-1 10-space rack and PS-1 power supply; 4B-1 self-powered 4-slot lunchbox; Aphex 2521 op amp, 1537A VCA IC and VCA cards  500A and 505.

Aural Exciters are essentially dynamic equalizers; as-in; rather than deriving their frequency-manipulation parameters from a set of fixed (or user-variable) static controls, the frequency-manipulation is, in one way or another, dependent on the program material. Furthermore, in the case of the Aphex exciters, the ‘equalization’ is accomplished not by the selective cutting and boosting of certain frequencies, but by essentially creating a distorted duplicate of some of the lower frequencies of the program material and then mixing this distorted signal back into the program with some amount of slight time adjustment; and all of this action is further dependent on the program level.

Aphex was the company that popularized these devices; in fact, many major-label records from the late 70s actually go so far as to credit these devices by name in the liner notes of the album. This was practiced in the early days of Aphex, when the devices were not even available for sale; instead, studios had to pay to rent the devices at a cost of $30 per minute of program material.  Consider what this meant.  If you were mixing, say, a 40-minute rock album in 1977, and you wanted the ‘aphex process’ used on the whole record, it would cost you $1200.  Which is $4300 in today’s money.  Wow.  Imagine if plug-ins were rented this way today.

I used one of the cheap-o ‘Exciter C’ units back in the mid-90s; it was a good way to compensate for the poor sound quality we experienced when bouncing down tracks on a 4-track cassette machine or the TSR-8 tascam 8-track.  I later replaced the Aphex with a slightly more advanced BBE 862, which operates on somewhat different principles but offers a very similar overall effect.  I still find the BBE useful in the studio; not for the ‘exciter’ high-end boost, which sounds very brittle and artificial, but for the powerful low-end enhancement it offers.  I imagine the plug-in sounds much the same.

Although Aphex may have brought significant advancement to the field of ‘psychoacoustic processors,’ of which the Aural Exciter is certainly one example, they did not create this product category.  Several devices were available as early as the early 1960s which promised dynamic, program-dependent equalization of audio material.

Once such example is the Fairchild 673 “Dynalizer” Dynamic Equalizer.  In an excerpt from an excellent post on Pro Sound Web, noted audio-expert John Klett describes the 673:

“673 “Dynalizer” Dynamic Equalizer – does a Fletcher Munson Loudness curve equalization and boosts highs and lows as level drops – like an automatic loudness control. This uses the same optical system as 661 and 663… kind of slow and stupid but – who knows – possibly useful as a “thing”. You would have to get the gain structure around this right to make it work “well”.”

In the download, you can also find information on Aphex’ small line-up of API-500-spec processing cards: the EQF-2 equalizer and the the CX-1 compressor.  I have never used these units personally, but according to this website they are in fact compatible with the API-500 standard.

Categories
Technical

Simple Tube Program EQ project

From the September 1947 issue of RADIOCRAFT magazine: an interesting ‘response equalizer’ project that looks to have great potential for use in the recording studio.  Download the complete article with schematics:

DOWNLOAD: ResponseEQ1947

You will need to download and read the article for complete details, but essentially this circuit provides the following functionality, with 7 controls:  4-position high-pass.; variable low-end boost with 4 selectable frequencies; 4-position low pass; variable high-end boost with 4 selectable frequencies; 10db overall gain with variable output trim.  And it does all of this with no inductors or transformers, and just one very cheap 6SJ7 tube.

To use this circuit in a complete studio-ready device, we will need to add several things:  First, an output stage capable of easily driving a 15k:600 output transformer.  I am going to try the very simple output circuit show above, taken from tubecad.com.

A 250-300v DC power supply (plus 6.3v filament power) will also be necessary; plus input and output transformers.  Once I get this all together, I will also need to figure out a good, silent bypass-switching arrangement.   Should be a good inexpensive tube eq project.   The overall application is very similar to the Pultec EQP-1A; this unit will not have as precise control due to the lack of inductors; but it will cost a heck of a lot less (likely $250 of parts verses $800 to build a Pultec).  Plus it allows one to boost and cut at different frequencies, which the Pultec does not offer.  Expect some build-notes, images, and audio examples here soon.

Categories
Early Electronic Music

Music Synthesizers in Popular Electronics 1972

Download a five-page article by David L. Heiserman on “Music Synthesizers And How They Work” from Popular Electronics magazine, February 1972.  Also included is a brief description and schematic for a ‘surf synthesizer’ project.

DOWNLOAD: SynthsPopElecFeb1972

Nice images of the Putney Synth and a Moog IIIc.  This article offers a very broad treatment of the subject, and it does not discuss music or music aesthetics very much; it is interesting though because it is intended for an audience with some technical savvy.  Everything in this piece can easily be applied to gaining a greater fluency with the software synths that we use today.

Naturally, any discussion of ‘music-synthesizers’ in Popular Electronics had to be followed by some sort of audio-synthesizer project; since this is 1972, the project is a Surf Synthesizer, aka a white-noise generator followed by a randomly-modulated low pass filter in sync with a VCA.  If you know what any of that means, you might could be interested in the schematic, which you can find after the link below.  I can imagine sitting at the kitchen table during the Nixon administration, carefully soldering this mood-enhancer while my wife macrames an Owl.

Continue reading “Music Synthesizers in Popular Electronics 1972”
Categories
Microphones Pro Audio Archive

Sennheiser 421 and 441 Dynamic Studio Microphones

Download three circa 1980 Sennheiser product-sheets for the MD-421-U and MD-441 microphones:

DOWNLOAD 421-U (color 4-panel): Sennheiser421_Color

DOWNLOAD 421-U (monochrome 2-panel):SennhesierMD421U

DOWNLOAD 441: SennheiserMD441

If you have spend much time in recording studios, you are probably familiar with these great microphones.  When we were kids first learning about recording, the 421 was the one ‘good’ mic that we had; we didn’t know exactly why it sounded so very much better than the assorted Shure, EV, and Realistic public-address mics that we had, but the difference was shocking.   A little while later I discovered the 441, which I find to be a less-exciting sound but still incredibly useful, especially when you want a really tight pattern and good fidelity (esp. under the snare).   Also good on the rack toms to reject snare and hat.   Stan Coutant’s excellent Microphone Data website has a download link for more current spec sheets on these models; I thought it might be useful to offer some earlier material here.