Friday, June 29, 2007

Celebrate Chladni Day! - June 29th

click on the image to see how Hugh Tripp Celebrated Chladni's work with an experiment you can do yourself!

Here is a nice portrait of young Dr. Chladni with a rather pleasant look unlike the oft-published late portrait showing him in an old coat and a ragged haircut.

I have devoted many posts to Chladni, a great but lesser-known scientist who elucidated many of the fundamental principles of sound propagation, and in doing so set the stage for quantum theory, the idea of forbidden or restricted modes, resonances, and also in other areas, such as astrophysics.

Chladni was the first serious scientist to show, with certaintly, that meteorites are of extraterrestrial origin. The discoveries and work of Chladni are very pertinent to our quest for superb sound. They show that the way ribbon mics, condensers mics and like physically move in response to sound is responsible for most of the timbre, tone, dynamics and other characteristics that we hear and either like or dislike.

And it supports our assertion that the principle of restricted modes works in favor on the ribbon mic, and against the tympanic condenser.

Here is a link to more about Chladni, who is celebrated on this day, June 29th, here in Massachusetts, and also in Maine and Puerto Rico.

Wednesday, June 27, 2007

Boxes O' Naked Eyes

This is what a bunch of Naked Eye ribbon microphones look like on the final inspection table where I and others give them the final scrutiny.

This is well AFTER they have been thoroughly checked electrically and acoustically. Sometimes during the handling of the mics a little scratch or something like a fuzzy bit of wood or other minor blemish gets in, and so that's where I come in to disrupt everything, finding the most minute specks and driving everyone here crazy. Yesterday we did a bunch of these and I noticed a tiny speck on one of the bodies, and that required some work on the microscope to fix - perfectly. Naked Eye may cost less but it receives no less care than any mics made at Crowley and Tripp. Each one is carefully made here using hand built methods combined with years of experience in making precision medical devices - medical products that must be good, or else!

Naked Eye is made right here, in Ashland Massachusetts, USA, between Boston and Worcester.

Go for the good stuff.

Crowley and Tripp no ka oi!

RCA 77DX Late Foil Style

The so-called foil versions of the RCA 77DX ribbon microphone were fitted with a stuck-on, printed foil, circumferential emblem in a shallow recess on the acoustic labyrinth, while the older ring style mics had a heavy chrome plated brass ring fitted into a deeper recess.

Externally, that is the only major difference between the old style and new style 77DX mics.

But inside there are numerous differences that I have noted. The way the motor unit is welded, how the wires run to it and how they are held in place with a kind of connector vary greatly from old to new. Other changes through production appear in cast parts, switches, the screws that vary the shutter, and apparently the transformer and reactor, perhaps small differences there. And they sound different too, no matter what ribbon is in, original or not.

I have been listening to the 77DX in the cardioid setting with the shutter partly closed. It sounds blocky to me that way. I can't really say that it is bad, but it lacks the openness and spatial feel we are accustomed to in the figure 8 mode. Another mic that has a hypercardioid response is the Shure 330 ribbon mic, same as that used on Carson's desk for years. It uses a side port system that basically makes up for having the back blocked off, which works at the higher frequencies to create a good deal of rear rejection.

Sunday, June 24, 2007

Fresca-Tenna Field Day

Yesterday was "Field Day", the annual event where the old hams go out with radios, generators, and plenty of beer and food to places to play radio and talk with other "field dayers" who are at parks, mountaintops, and unusual locations around the globe.

The idea is to be able to get out and communicate in the event of some sort of emergency, and in particular, if a war breaks out. That's why the US government and other governments tend to protect the hams and their incredibly valuable spectrum space, just in case they need it, because they can take it all back with one order. This is true in virtually every country on earth. So hams are "holding the frequencies" so to speak, until some bigger need arises. It's a fair deal because spectrum is so costly and valuable and people like me who like to experiment with communications, antennas, audio and electronics have a place to do it, at no charge.

The Fresca cans and wires were my field day antenna. I talked to a guy in Hawaii on two Frescas and drank the contents too. From my own backyard. No need to go to the park. I imagined the invisible waves spreading out over the earth from just my tiny spot, yet able to be heard thousands of miles away in just a few milliseconds, and they don't stop there - they keep going into space, where they are still traveling.

New Old Stock Shure Starlite Model 215 Ceramic Microphone

I came across two of these unopened, sealed, mint, preserved examples of the Shure Model 215 ceramic.

It has the directions for use (here is a pdf of the spec sheet) and the warranty card, and that nice looking red, white and black tag. The mic is wrapped in Illinois brown paper like a sandwich might have been, and the external colors of the box are unblemished and unmarked. There is a small stain on one of the labels, but the other is perfect.

Hamfests and ham radio flea markets are excellent sources of all kinds of arcane microphonia. This one has been added to the Microphone Museum at Crowley and Tripp for visitors to enjoy - but they can't unwrap it!

Ceramics mics and other ceramic or crystal transducers utilize the piezoelectric effect, where a voltage is produced in proportion to a strain on an oriented crystalline or crystalline/composite substance. Many materials exhibit the piezoelectric effect, even many hard plastics, even the plastic in an XLR connector, which I found ut about when I dropped a cheap cable end on the concrete floor, the other end connected to our preamp and headphones, and I could hear the impact! Aha, I thought, here is the ultimate mic for recording large explosions, even nuclear detonation. Just use the connector! Check it out for yourself.Go get one of those really cheap RS cables and listen, then go out and get a good cable.

Piezoceramics are composite ceramic, generally hard materials, sort of like the same material that a teacup is made of. They can be shaped and made into transducers, pickups, microphones, and buzzers, beepers and nanoactuators. We use them to make ultrasound transducers for use in Intravascular Ultrasound or IVUS, to see blockages in the arteries of the heart.

Saturday, June 23, 2007

Polyester Leisure Suit Materials

There are a lot of people who remember, but won't admit they ever owned, a leisure suit. The 70's were like a messed up transitional version of a decade-long alcohol, sex and drug hangover from the prolonged party of the late 60's. Historians will note that the funked, stoned, greasy yippie unwashed student mob eventually found showers, shampoo, and some new clothes,and succumbed to the throb of disco beat and mixed drinks, thereby getting close to many persons of the desired sex on a regular basis with no effort.

I did not ever have a leisure suit. But, I had several polyester shirts. One had a pattern like a chainlink fence on it. I remember this because a nice young lady who is now a rather well known astrophysicist pointed that out to me, as I stood next to a chain link fence near General Cinema. Polyester shirts pick up other chemicals, and I smelled like cigarette smoke (people smoked everywhere at that time and it didn't matter if you smoked or not, your polyester shirt would still stink like coffee, cigs and cream-filled cruellers from spending 35 minutes at a Dunkin Donuts.)

The feel of polyester on skin isn't very nice, which explains why pure polyester clothing isn't very common but blends with other more comfortable fibers, such as cotton, are in most wrinkle free fabrics. Cotton is a favorite material for the microphone maker, as it hardly changes over time, a fact noted by the Egyptians several thousand years ago as they prepared the dead for the afterlife.

Had the Egyptians used polyester, all of those mummy wraps seen on The Discover Channel would have lost any pliability by now.

Most, but not all condenser microphones, use polyester diaphragms in the capsule. But which form of polyester is used, and how does it change over time? How does the sound of a mic change over a long period and do the vintage mic capsules still in service today sound like they did when they were new?

Variously referred to as Mylar (which is just one type of polyester film out of hundreds) this material is a thermoplastic with many uses such as plastic bottles, film sheeting, product packaging (that tough untearable stuff manufacturers use so you have to destroy the package, which reduces store returns) and numerous medical devices, such as catheters. It is very tough!

But polyester has a dark side too. It sometimes aborbs water unless post processed, and it can age harden, be embrittled by heat, damaged by UV, and it picks up a lot of environmental chemicals and smoke films very readily.

DuPont makes many chemicals including this as described by them:

  1. When you're looking for the ultimate combination of stiffness, temperature performance, maximum dimensional stability, and a high-gloss finish in glass-reinforced resins, Rynite® PET thermoplastic polyester resin is the most cost-effective answer. It unites the best properties of reinforced polyethylene terephthalate (PET) with easier processibility to produce high-performance parts that can be molded conventionally.
  2. Rynite® PET is formulated with a unique rapid crystallization system. It also has a 20°C heat deflection advantage over PBT. It can be processed over a broad temperature range.
So, which of the many forms of polyester are used in Neumann TLM-103s, or Feilo or Alctron or 797 Audio? Do Oktava buy "off the same roll" as AKG?

Ribbon microphones missed the Polyester Revolution. Ribbon mics were mostly out of production by the time Polyester appeared under the disco ball. Harry Casey (KC and the Sunshine Band) is arguably one of the more important musical artists of the 70s.

Thursday, June 21, 2007

Chladni Patterns

Chladni day is held on June 29th in Massachusetts, Maine and Puerto Rico, so we are preparing here for the event in the usual way, looking at Chladni patterns produced by sand spread over metal plates that are bowed with a violin bow. Here they are for your enjoyment too. Note that in these examples, all squares, many right angle modes are supported. Of course there are three, not two dimensions at work here, and the orthogonal modes are as much an indication of lateral and axial motion, together, at work to produce the complex and surprising nodes and antinodes seen here. On a guitar body, for instance, the patterns are much more complex. Even a circle can produce complex patterns, and "break up" at the higher overtones to produce up and down motion simultaneously, leading to comb effects in certain microphones that are not design to suppress Chladni action.

But we are celebrating, not suppressing Chladni, at least not next week. Chladni was an important scientist who, among many other things, was the first to convince the scientific community of the the time that meteorites are of extraterrestrial origin. That was important.

Great fun with Chladni! Click on this link to develop your own Chladni patterns using circles or rectangles.

Chris Regan at AES Vienna

Here's a shot we got from the recent AES meeting in Vienna, Austria, where product manager Chris Regan did three or four straight days of demos of Crowley and Tripp ribbon microphones.

The candelabra arrangement is a handy and relatively portable setup that holds the mics by a locking base mechanism designed and built by Hugh Tripp, who comes up with these types of things on a daily basis, it seems. A low noise switch selects the various mics so visitors can hear the difference in tone color and pattern that make up the Crowley and Tripp line of voiced, purposeful ribbon microphones.

That candelabra has some miles on it now, and from the look of this picture, Chris did too, probably an early morning shot several time zones away from Boston-normal we are used to..

AES Europe is a great show for us even though it is relatively small, and this year's location, near Germany, helped firm up sales in that country and others, where we are doing quite well, thank you.

Sunday, June 17, 2007

Naked Eye Ribbon Microphone Review - Mesa Amp

What can I say about the sound of the Naked Eye ribbon microphone up front and personal on the face of a combo amp like this recent vintage Mesa? Here it is placed off the edge of the cone a bit with the dark side facing in, probably to get a thickness and density thing going, which sounds incredible. Of course, all you have to do is loosen the mount, which is designed so you can put the mic right up to the amp, even IN the cone of the speaker if there is no grill cloth, and rotate it until you get just the right sound, the one you like. It is so easy to get correct mic placement on an amp with this simple mount and you never have to worry about hairnet rubber stretchy breaking doodads again.

Of course, you can use a regular mount. Go wild. Another thing most people overlook is suspending the mic by its cable over a stage or in front of drums and up high. Yes you can do that.

Saturday, June 16, 2007

Alarming News from Gibson

Apparently we are flooded with counterfeit Gibson guitars now. Who will be next? I would like to know exactly what the US Federal Trade Commission, the agency charged with policing this type of thing, is doing, if anything.

Note: The picture provided as a link is real GibsonLes Paul as shown by Dallas Guitar repair. You can count on an expert repair shop such as Dallas Guitar Repair to know a genuine instrument from a fake. Recommended website full of great guitar info!

April 2007
Gibson Guitar Warns Consumers About Counterfeit Instruments

Press release
Source: Rogers & Cowan

Gibson Guitar, the world’s premiere musical instrument manufacturer and leader in music technology continues to protect its intellectual property rights and provide consumer protection against the growing problem of counterfeit instruments being shipped from and sold by outlets and individuals in China.

further excerpt:
Consumers can check any of the references below when examining a Gibson guitar in an effort to insure its authenticity:

-Make sure the size is not undersized

-The headstock and headstock logo should match those of authentic Gibson guitars

-Pearl should always be inlaid

-Les Paul Model script is always in cursive

-If the guitar has a 3 screw truss rod it is not authentic

-Check the control and pick up cavities for sloppy routing or wiring

-Real Gibson guitars use one piece necks

-Many fake Gibsons have their pickup cavities painted black inside

-If purchasing a Gibson always ask for the Gibson’s Owner Manual and Gibson/Warranty Inspection Card

-Check the wiring, if it is plastic it isn’t a true Gibson

Other information on spotting a fake guitar can be found on

Read about it here.

Tuesday, June 12, 2007

Naked Eye and Soundstage Image on Piano

Even though figure 8 mics can be hard to use on piano, and small diaphragm condensers such as Earthworks and others have appropriate accuracy and small aperture for the difficult area under the lid, so to speak, along comes someone who tries a couple of Crowley and Tripp ribbon mics on piano.

New sounds and ways of presenting sounds require an open ear and open mind. I like smoothness and lack of harshness, which is why I prefer the admittedly mellow sound of ribbon mics in many applications, and while I haven't been such a strong advocate of the use of, say, Naked Eye on grand piano, the samples linked here at least make me open my ears a little more.

Take a listen here.

Sunday, June 10, 2007

Ham Radio at Tape Op Con 2007

Ham radio, amateur radio, free public access to regulated spectrum space - it's all about bandwidth and a place to experiment and develop new techniques that today are fundamental to recording, broadcasting, music making, shielded cable, medical imaging, cell phones, wifi, television, spectrum analyzers, compressors, two way radio and dozens if not hundreds of electronic technologies we use every day.

Here two hams, Bob Heil, FCC callsign K9EID, and Bob Crowley, FCC callsign W1XYZ, have an informal chat during one of Lynn Fuston's recorded radio interviews during Tape Op Con 2007 in Tucson. Both avid antenna designers and microphone makers, Bob and Bob share a common interest in all things wavelike, and all things musical, and everything in between or in combination. Bob Heil described with great fervor how his early days in ham radio were his college education in electronics, acoustics, antennas, transmission lines and sound engineering. Bob Crowley discussed new developments, some based on ham radio technology, that today are used to see clogged heart arteries, find cancer at a very early stage, and how they relate to absolutely new ways to improve the efficiency, purity and quality of recorded sound, and Made in USA Crowley and Tripp ribbon microphones including the phenomenally popular Naked Eye ribbon microphone. Advances like that are noticed, it seems, and so interest and anticipation of what is to come is high. That's the way it should be, and the pro audio and recording sector today is a vital and growing industry.

There are a lot of ham radio types who belong to the Tape Op community. Not only Doug Fearn, famous for high quality preamps and compressors, or Rick Perotta, president of Royer (not present this year) - but a lot of ad-hoc experimenters, tinkerers, thinkers and technology developers inhabited the el Conquistador Resort for three days of merry making, music listening, and BSing.

For those hams who have stumbled unexpectedly on this blog: Events like Tape Op are the new hamfests, with a younger and more diverse crowd, eager to try new things. Do you think we should tell them about our spectrum, estimated to be worth over 6 billion dollars at present spectrum prices, and let them have at it? I do.

Saturday, June 09, 2007

Report from the New Mexico Border

The winds were too high yesterday near Sierra Vista for light planes to fly over to Carlsbad New Mexico, not far from Roswell.

But as luck would have it, Icame across this forlorn, isolated second hand store with the "big sale" sign near the Southernmost portion of Arizona West of New Mexico. In the back, I was told, were minerals, fossils, stone artifacts and meteorites. That got some attention.

There are generally two types of meteorites: stony, and metallic. The metallic meteorites, when carefully cut with diamond blades, polished and etched with various acids, sometimes show unique and definitely non-terrestrial crystalline formations that may have unique properties. Crystals grown very slowly, perhaps over the course of 4 billion years, can have a perfect, defect free structure that rivals lab grown crystals, and the alloys, some with nickel, others perhaps titanium,can be exotic.

Turbine blades for fan-jet engines are made of what is like a single pure crystalline shaft, which is necessary because of the extreme tensile strength requirements.

Ribbons for ribbon microphones are usually made of ordinary aluminum. Aluminum is beaten or rolled very thin, and cut into strips which are fragile and easily deformed. There are various alloys and in this blog there are several pointers to the alloys of aluminum. Could the metallic crystalline structures of meteorites have properties useful to sound recording, even ribbon mics?

Thursday, June 07, 2007

STC Commentator's Ribbon Mic from Larry Killip

Here's a great shot of Larry's new (old) STC (Coles) Commentator's mic designed for close talking broadcast applications. This is probably one of the most unusual ribbon mics ever made, as it has a ribbon mounted in such a way that you talk across it. The STC Commentator's mic is also designed to eliminate wind noise. That bar is the "lip" bar you hold against your handlebar mustache during the cricket match.

I haven't seen one recently and forgot how large it is - the last one I saw in person was at the Royal Birkdale Country Club near Blackpool England. I was there with my dad when he played golf in the Carling World Open held there in 1966. It made a big impression and I never forgot it.

Larry writes:

"I've tried it briefly but couldn't get much out of it at first try which didn't make sense as it looks fine. I'll check if the XLR is wired correctly, or the other possibility is perhaps the ribbon connections have corroded a little. it arrived on my doorstep this morning, and the first thing I did was take the cover off!! There's a wee little transformer in the handle. Won't take much to suss it."

July 19, 2007: I see there is a story still up on ABC Australia about this mic. Link here.

Sunday, June 03, 2007

Free Tube Testing

Down in my basement, next to the furnace, is this RCA store type tube checker that was used to test for shorts, emission and basic tube faults, and also store new tubes for sale. Bob McTeague, "tube man" sold this to me at the MIT flea market years ago, and it is excellent. At that time I realized that this tube checker was technically inferior to my Weston transconductance tester which measures "real" tube performance, but I use this one more frequently, simply because it is handy and always ready to go.

Most of the time it just gets used to ID a bad guitar amp tube, or sort through piles of used Telefunkens and Mullards I pick up at hamfests. Some of them are usually fine. Then both new and used go below as follows:

Shelf 1: 6L6, 6550, 6V6, 5881, 7027A, 6F6, 5AR4, 5U4 etc.
Shelf 2: 12AX7, 12AT7, 6AU6, 6AL5, 6GW8, and so forth
Shelf 3: 1L6, 6CW4, 6DS4, 13DS4,VF14, and a lot of other minis and Rx tubes
Shelf 4: 8930, 4CX250B, 2C39, 805, 807, 810, 4CX1000, 4CX1500B and more tetrodes.

Acoustic Modeling Software

Comsol has several physics packages, or modules,that work with Solidworks and several other CAD programs in use at development labs. Some of the modules cover finite element analysis of magnetics, RF emission, charge distribution, and here, acoustic propagation, all in nice colors.

The ability to compute and visualize dynamic physical phenomena is a fast growing product area that is becoming essential to many industries such as aerospace, medicine, industrial automation, product design, and even new microphone design.

Tape Op Side Trip to Carlsbad NM - Legendary Metal Hunt

It's a long drive but a short flight to Carlsbad NM where I intend to take a little side trip during TapeOpCon 2007 this year. It turns out there is an antique store there with "space junk" that I want to check out.

A lot of people know that although I do not put much credence in UFOs, alien abductions and the like, I am a listener of fellow ham radio operator Art Bell, who has on occasion interviewed two people who have bits of material alleged to be from the UFO crash site in Roswell NM. What intrigues me about these 1996 interviews (transcripts of program click here) is the combination of poor observation mixed with some astounding details. Just enough to have stuck in my mind over the last ten years or so.
Naturally, any new metal, especially a super lightweight, strong alloy that could be used for, say, an indestructible and ultrasensitive ribbon microphone, (for example!!) is something we'd want to know more about! We have been experimenting with some pretty exotic composites and alloys ourselves, done a lot of work with superstrong carbon nanotubes and polymers since the mid-90s, and have even named one "Roswellitetm" in honor of the legendary supermaterial found at Roswell. These are a few of Soundwave Research Laboratory's proprietary technologies, such as SuperMattertm advanced materials.. Last year at Tape Op I could not get a meeting to see the so called "space junk" but did manage to get to Tombstone to visit my pal Steve, who owns a small plane - good enough to make it to Carlsbad.

SuperMatter advanced material, Roswellite advanced material, Crowley and Tripp brand, are trademarks of Soundwave Research Laboratories Inc. Ashland MA USA. All rights reserved.

Saturday, June 02, 2007

True SystemsP-Solo Ribbon Preamp and Crowley and Tripp Ribbon Microphones

Recently we've been doing extensive testing of True Systems P-Solo ribbon preamp and the Studio Vocalist and Naked Eye mics.

Sometimes two pieces of gear go well together, and this is one of those times!

We are amazed at the low noise and high gain of the P-Solo, and how it brings out every nuance of articulation and tone when used with our mics.

We like it so much that we are recommending it to our customers.

Check out True Systems P-Solo ribbon here.