Tuesday, November 06, 2007

RCA Gas Pedal - Rear View - MI-6203-D "LO" Version SK-50 Varacoustic

I like to refer to the improbably named RCA MI-6203-D, "LO" (or is it really M1-6203-0/), aka, the SK-50 Varacoustic variable pattern ribbon microphone, utterly forgettable either way, and homely as can be in the American connotation of the word "homely" as THE GAS PEDAL.

This highly unpopular yet ubiquitous device has almost the exact same motor unit as the famous and most desirable 77D and 77DX ribbon microphones. The Pedal sports a rear mounted, spring tensioned pattern selector, dubiously marked " PU12V", which performs the exact same function as the luxurious rotary nautilus shutter cam of the more wonderful 77DX, but in a far far less exciting way. The oft-mentioned RCA style acoustic labyrinth, filled with a combination of jute felt, horse hair and paraffin-soaked to get just the right amount of attenuation, is lovingly stuffed into a squarish, nondescript black bakelite block in the base of this beast.

The dynamic lines and Art-Moderne streamlining of the MI-6203-D "LO" version and its somber, almost funereal color scheme, plus the aforementioned lyrical "PU12V" nomenclature, cannot make up for its sheer lumpiness and uninteresting aspect. Such a thing could hardly sound good, so unbeautiful as it is, you might think.

But not so! The sound of this toad is probably at least as good as any Ningbo-ribbon mic of today, and far more versatile, with its springy thing, allowing for various pattern changes, all which make a ribbon sound like a dynamic, save the figure 8 position. So save yourself some money, go on ebay, and scoop up one of these lumpen objects, at a very good price. The one I have comes with its own "Microphone Stand Model K5-4A".

One wonders what happened to K4-5A, or if there ever was a "4B" model - certain to pique collector interest I'd presume. Such minutia is of interest to no one except the terminally nerdy, a special club in which I confess membership.

Product naming is an art. RCA got lucky with the 77DX. 7 is a lucky number used in lots of high end products, such as finicky BMWs, and DX has all kinds of mysterious connotations from the broadcast and radio art, the main one being "long distance". Even today, hams call a long distance contact "DX". But letters and numbers can get confusing, or worse, generate an aversion which prevents anyone from remembering let alone mentioning letters-numbers-letters type names, unless the company is very careful. You may hear "I used a 77" and know what that means. You could also know for certain what's under the hood if it is a "V8". But what about the very unlucky MI-6203-D "LO"? Not too likely you'll hear that one thrown out at a cocktail party, or even at AES.

Ever wish the US media would stop saying "went missing" or "gone missing"? If you think this sounds like something Jethro would say to Jed, you are not alone. Amazingly, we can blame the British for originating this insult to the English language. Somehow, the term "went missing" when spoken with a proper English accent, sounds nearly acceptable, yet anyone from the Deep South who utters the phrase might be mistaken for an illiterate. It just ain't so!


Anonymous said...

Went missing is like "gone fishing". Is is not incorrect, but it is affected speech. "We went sailing" seems alright.

Unknown said...

Being a transplanted southerner, I have to say I disagree with your end rant against colloquialism. That said, I've never heard more poetic word spoken about microphone bodies and model numbers.

Bob Crowley said...

Certainly not intended to be an insult to the Deep South or its ways of speech. Twain and Faulkner are my favorites. There are some linguists who argue that American South colloquialisms and accents are closer to the orginal speech during the colonial era. I find accents fascinating - here in the Boston area we have many different versions, including South shore (shoa) North shore (Nowth shoa) Newton Center (Centa) and Wester Ma we have Terrible (Tearable) and Cheese (chees with no Z).

These sound quite odd to the American South, even annoying.

Another interesting "regionalism" is the "coastal" accent heard from Maine at least as far South as the Outer Banks. It is like a thin line of old culture specially delineated on the sand and coastal islands, but not inland.

In any case, that clipped BBC accent offsets my perceived discomfort with "went missing", but now it has been parroted by every local TV newscaster here in the US, it sticks out.

Yes, a rant. Please excuse my occasional ventings. You have no idea of how many never see publication.

Unknown said...

To quote my mom, "I'ma hearin' that." I think the issue with the newscasters is the misuse of language in an attempt to sound authoritative or smart. It's the same as when someone says "..a conversation between Bob and I" rather than (the correct) "..Bob and me."

PS- How can I learn more about "Roswelite" and "nanotechnology" (terms being thrown around with reference to the new mikes)? All I can find are surface-level references, but I want to know what exactly is so exciting about your new work.

Bob Crowley said...

What is exciting about Roswellite is the ability to mimic the "foil" ribbon but not have any of shortcomings of foils, such as deformation, breakage and manufacturing difficulties.

But I think you are asking about how it works and what it is, right? It is a superelastic composite with paramagnetic properties. Like Nitinol, it can be bent or stretched and pops right back in place, unlike Nitinol, it is paramagnetic and has higher conductivity than Nitinol. It also has much higher tensile strength than aluminum.

Roswellite is the trademark name of a class of materials we are developing which we refer to with another trademark - Supermatter. Wow that sounds cool huh? Anyway all it is about is applying everything you keep hearing about "nano" to existing problems, mainly material problems. How to get conductivity without adding weight, how to get high flexibility while getting higher strength. I haven't gone into the details of how we do it on public forums because there are people out there who will copy or try to copy (which is not easy in this case) but if they are determined they will eventually do it. So we leave that to the patents and the people who research them, and to be fair, we have even given pointers right to certain patents and other writings that are available to you.

That being said, it makes a better ribbon mic, one that won't break, and will stand up.

Unknown said...

Very cool, the what and how are definitely my (dilettante) interests. Thanks for the further info. It makes a lot of sense, after a few Wikipedia searches.

newyorkbrass said...

I am dismantling a RCA varacoustic and after much testing i was hearing an "undertone" when loud trumpet is played - like a distortion component in the bass direction (!) This is because the trumpet is mainly 2nd harmonics so this somehow emphasizes these harmonics. Upon disassembling the labyrinth i discovered it is completely empty and is basically a helmholz chamber. Shouldnt there be damping material inside as you described? do u have ideas on what can be used to replace if indeed it was "cleaned out"?

Bob Crowley said...

The material RCA used is kind of a mystery. There are comments about it on 3dbaudioinc.com I think. I wonder who "cleaned it out" and why? Clarence Kane may have an answer, or Big D mics.

Sorry I can't be more help on this.