Hey it’s one of those old horn speakers

Along the lines of the ‘Carbon Mic’ (see earlier post) are these early horn speakers.   They are visual icons that have become separated from their actual sonic function due to the fact that they do not interface with any other audio equipment that any normal living person would own.  But don’t those things look great?  yes they do.  They look very similar to the acoustic horns that are mechanically coupled to the needles of ancient record players, but in fact these are electrical.

here’s an example of a very old record player which has a horn mechanically coupled to the needle:

On the other hand, the early electro-mechanical horns were made for use with early Tube radios. They have drivers with permanent magnets attached to the base of the horn.  Driver:

These type of speakers date from the 1920s, and they are the earliest common electro-mechanical transducers.  I picked up this example, made by Music Master of Philadelphia, at a yard sale.

Here’s the base of the unit, which contains the driver.

i plugged the very frayed cloth-covered wire into an old receiver and…  sound!  it worked.  the volume level was very very low, tho, even with the 50 watt receiver turned up all the way.

Turns out that these early speakers require a slightly different sort of amplifier than we use nowadays.  Not surprising.  So i built something to do the trick.  I describe the process below for those who want all the bloody details.  Once i had this thing running properly, tho…  the big question… how does it sound?  well, when listening to music recorded in the 1920s (like my Blind Willie Johnson), it sounds fine.

Later music sounds pretty bad.  and not even in an interesting way.  just bad.  But old classical and gospel are cool.   Hearing those old recordings played back on the same sort of system that folks would have used 90 years ago…  wow.  it’s fun.  I have the horn (and it’s attendant special amplifier) hooked up to an Apple Airport Express which hides in the base of a corner cabinet in our house.

Other rooms in the house have their own full-range systems with their own Airports, so it’s really easy to switch up the playback systems depending on mood etc.  Love iTunes on the laptop.

Here’s the tech-y stuff for those of you who care.  So why did the speaker not play back at a decent level when used with my old SONY receiver? A quick bit of online research revealed that these old horn speakers have an effective impedance of 1000-2000 ohms.  WAY off from the 8 ohm speaker output of a contemporary receiver.   Anyhow, to confirm this, i inserted my handy University Sound universal impedance matching transformer (wired to couple 8 ohms to 600 ohms) and what do you know.  the speaker worked fine.   Decent volume level with the volume knob set at 10’o-clock.

Anyway, rather than run this thing all the time with a giant shitty receiver, i decided to simply build a tiny 5watt tube amplifier with the highest impedance that i could easily generate – 600 ohms.   I had some Edcor 5K/600 single-ended transformers lying around from a mic preamp project that i aborted because…  well…  the Edcors don’t have enough low end response to make a good mic preamp.  In this decidedly lo-fi application, though, they work just fine.  I used a 6J7 (for the old-timey look) into a 6V6 tube with a 5V rectifier.  I initially built the unit with a 6L6, but the edcor was getting REALLY hot (i guess they mean it about the 5watt rating) so i switched the tube to a 6V6 (and changed the cathode resistor appropriately).  It runs cool now.

Anyhow, this little amp also has the added feature of two RCA input jacks that passively mix to the input grid of the 6J7.  which is a necessary feature since i use this to listen to (stereo) music from iTunes via the Airport Express.  Also: super-nerdy but maybe worth mentioning – dig the old ‘screw-lug’ speaker connection.  i have been using these a lot lately and i think they add a little charm, even tho they do generally require some dremel-ing to the chassis in order to mount. (i hate the dremel and will do almost anything to avoid it.  Greenlee punches 4eva)

If you find one of these speakers for a good price (mine was $25, down from the sellers asking price of $80), and you can confirm that it works, you might want to pick it up.  One caveat: i apparently got lucky with the speaker that i bought.  Apparently, it’s common in these older units for the magnets to actually have lost their charge, and if that’s the case, they will need to be re-magnetized using wire and very high voltages.  Dangerous and irritating.  There are a few pages on the web that describe this procedure.  It’s pretty incredible to me that this technology is so old that the magnets have lost their charge.  crazy.  will this happen to all of our permenant magnet speakers some day?  will all of those coveted old Alnico drivers be useless at some point?  when?  2050?  Can’t wait for “The Day The Tone Died”  haha i can’t believe i said that….   awful.    Hate ‘Tone’ as a synonym for ‘pleasing sound quality in an electric-guitar sound reinforcement scenario.’

Does anyone out there use one of these speaker systems for music listening?

Anyone have a dedicated ‘antique’ system for listening to certain genres/ periods of recordings?

About the header image on this page…

The main page of this site is currently displaying a small sliver of the image reproduced below.  It’s a page from a SONY consumer electronics catalog (Japanese) from the early 70s. 

I pulled this page from a website that i sometimes refer to as The Greatest Website In The World:  the “product design database” of the Quatre Design Corporation.   I have no idea what the Quatre Corp is or what they do, and i have no idea how i stumbled upon this page…  feel like it was in the pre boing-boing era…  anyway, check it out.  Basically, these Quatre folks (likely industrial designers) have hi-res scanned and archived hundreds of Japanese-language consumer electronics and automotive catalogs from the past 50 years.


This is a veritable goldmine of 70s audio hardware, as well as some of the wackiest audio marketing concepts that I Have Ever Seen.  Check out the SONY catalogs especially.  There is something so great about this style of photography.  the soft light, the ever-present gradient background…  it’s so dreamlike and futuristic all at once.  Get ready to waste some time…

RECORDINGS: Steve Douglas “the music of cheops”

Steve Douglas was a studio session saxophone player who performed on countless hits of the 60s and 70s.  Allmusic.com has a write-up and credit list for Douglas if yr curious.   In the mid-seventies, Douglas apparently went to Egypt and got permission to record some improvised music in the Kings Chamber of the Great Pyramid of Cheops.  Here’s an example:

09 Track 09

According to the liner notes, the whole thing was taped live by his buddy to 2-track Nagra tape deck (a Nagra is a high-end Swiss-made tape recorder which was generally used on film and television shoots in the era before DAT tape decks).  I am not sure how to explain the polyphony (IE multiple notes occurring at the same time), but it’s possible that Douglas was playing two saxes at once, a trick i have seen myself many times.

From what i can gather, this was originally a private press LP that was soon picked up by Takoma, the avant-garde/folk label.

This recording really illustrates how much information there is in simply hearing the sound of a room.  How much can be added to a recording by putting the performer in the right space.  The room sound of the chamber is the real content of this album.  Douglas brings this point home by including some brief ‘street noise/Cairo’ bits on the record; it lets us know that we are in for a largely sonic (as opposed to largely musical) experience.  I was in Cairo recently and it is a very visceral place.  noisy, crowded, smoky, strong smells everywhere- it’s overwhelming.  Even the pyramid park is stressful.  Cops with machine guns circle and extort money from tourists (yes for real).  In contrast to all of this is the inner quiet of the pyramid chambers.  Silence, darkness, no motion.  Check out this clip where we hear a percussive piece that seems to be wholly constructed from the valve and pad noises of the saxophone.


Douglas was not a really a jazz musician (although there are certainly ‘jazzy’ passages and scales on the record), and i think that’s part of why i like this album so much.   Jazz musicians tend to focus their energy on certain kinds of expression:  usually personal ’emotional’ expression, or some expression of their thoughts on jazz idioms and jazz form.  CHEOPS, though, is an audio expression of the physicality of an incredible place.  It is really just about the sound, and it’s beautiful.  I transferred this album from LP.  It’s available on Amazon (with a really terrible new cover), and if you like Eno, Budd, etc., i think you will dig this.


Does anyone know anything else about this record?  What sound effect units he is using?

Any similar records out there to hear?

ICON: “gimme one of those real old mics…” :::UPDATED:::

When you are creating a set for a musical performance, nothing says ‘old school’ and ‘authentic’ like one of those mics…  those real big old mics with the springs…  what the F are they called?  Turns out that they are called Carbon Microphones, or more specifically, Double Button Carbon Microphones.

And while many a rapper, RnB singer, or songwriter type may favor them for their music video, i can promise you two things:  *)no one would be able to actually hook the mic up and use it, and *)if they did, they probably would not dig the sound.

Carbon mics are the oldest microphone technology still in (albeit limited) use today.  They actually pre-date vacuum tubes.  Wikipedia has a great article on their history and use, so no need for me to retread those waters.  Carbon mics are used in landline telephones, so we all have a basic idea of what they sound like.  midrangey, a little crunchy (distorted), compressed…  hey wait a minute!  that sounds pretty good to me!  Aren’t there like a million expensive DAW plug-ins in order to give you ‘that sound?’ Anyhow, we all know in general what they sound like… but how do those big old music-video props sound?

In order to find out, it turns out that it’s necessary to actually build a power supply.  Carbon mics need a few volts of a DC current moving through them in order to operate.  I found this handy schematic online and put it together.

I added a DC voltmeter so that i could monitor the effect of varying the voltage on the sound (the mic i have seems to like 6 volts).

I used a double-button mic input transformer salvaged from an ancient tube PA head that i had.  To the output of this transformer i added a second transformer to bring the impedance back down to Low-Z mic impedance so that i could use this whole rig with whatever mic preamp i wanted to.  The particular mic i have is a Lifetime Model Six.

I bought it years ago on eBay along with a little tube amp and some shitty speakers (and about a mile of useless rotten old speaker wire) for $150.  Anyhow, i won’t bless you with any vocal performances, but here is an acoustic guitar recording from my living room.  The left channel is the Carbon mic.  The right channel was recorded simultaneously with good equipment (414/omni into an API 512) so you can get a pretty good idea of what i was hearing in the room.  I put a little EQ on the Carbon mic to make it more audible (low pass at 3k, 5 db peak at 1.7K). No other processing was used.  Check it out.


Does anyone out there use double-button Carbon mics for audio production work these days?  Music recording? Sound design work?

I heard recently (maybe Tape Op mag?) that someone was making new-production ‘professional’ carbon mics.  Has anyone used these?  thoughts?

UPDATE: I recently had the chance to use this Lifetime Model Six Carbon Mic in a modern-recording context.  We tracked the following cut at Gold Coast Recorders, using the Lifetime for the vocals.  It sounds pretty outstanding…  I feel like you could get 90% of the way to this vocal sound with an SM57 and a fuzz pedal, but that extra 10%…  it’s a game of inches, ain’t it.   This is ATLANTIC CITY, my studio project with T.W.   Take a listen:  Ten Past Midnight


This is a website about audio.  More specifically, the history of audio, and our relationship to audio.  Audio, broadly defined, is the electrical representation of sound.  Sound has existed for at least as long as anyone has been around to hear it, but audio is a relatively new technology.  The ability to ‘capture’ sound and then ‘play it back’ divorced from its origin in time and/or space is the most basic function of audio technology.   In addition to this role, audio technology can also be an instrument; a tool to create unique sounds that do not originate as acoustic sound.  I do not mean to imply that these are separate functions; capturing and playing back sound will always change the sound, regardless of the intent of the audio operator.   There is always a grey area between documentation and manipulation; every audio operation creates the potential for a new sound.  We have developed a great many audio tools and technologies to maintain the ‘fidelity’ of audio: that is to say, maintain a ‘true-to-the-original-sound’ quality in our audio signals.  We have also developed a great number of tools and technologies to enhance, distort, combine, separate, and generally manipulate audio.  It is these tools and technologies that I am interested in exploring.  I am interested in their effects, their methods, and their development.  Most of all, I am interested in their potential to create meaning for the people who experience these new sounds.  Sounds that have been brought across great distances, through spans of time, bearing the artifacts of the particular tools that have crafted them.

I will not be presenting a chronological narrative.  I am not attempting to offer a comprehensive or thorough treatment of audio history.  Instead I will focus each post on a particular subject: a technology, a technique, an individual, a recording, a piece of hardware.  I will provide historical context, and offer my thoughts about what significance the subject may have.  Some posts will be very broad in nature, and some will be fairly technical.  Much of what I write about will stem from my own experiments with audio hardware and techniques.  I hope you find the information useful.

information and ideas about audio history