Can Microphones Block Out a Diesel Locomotive’s Roar?

I don’t claim to be any kind of expert in this arena… I’ve recorded on lots of different mics and thought I sounded better on some than others, but a lot of it has to do with what I was reading and how I was reading it.

Yesterday, I posted about a job where I had to voice match myself, replacing audio I recorded two years ago. One of the interesting things about this job was the microphone I used.

The studio where I recorded has no traditional sound booth. In fact, my recording was done sitting at a desk with a bunch of computer and audio equipment on it. About 4 feet behind me was a big window, looking out to a Chicago street, just a few blocks away from one of the biggest train stations in the city.

At one point, I was recording and I stopped as a train was passing nearby. The clack-clack-clack of the train wheels over track seams and the engine roar were pretty loud, so I stopped reading.

A few seconds later, the producer, who was listening from another room where he was actually laying the audio down to a computer, asked “Is something wrong?”“I just figured I’d wait for the train to pass,” I said.“Oh, I didn’t hear it. I’m still rolling… just go on when you’re ready.”

So how is this possible? How could I record “clean” audio in a non-sound treated room with a diesel locomotive passing by just a few blocks away?

The answer is in the microphone we were using. A handheld job from a company called Coles – the 4104 Commentator’s Noice Cancelling Ribbon Microphone.Designed in the 1950s by Dudley Harwood and D.E.L. Shorter of the BBC, the 4104 is a pressure gradient ribbon microphone with a lot of acoustic dampening. What this means is that it’s very good at picking up the speaker but little else.

While the technical aspects of how this is achieved are beyond my knowledge (and, perhaps, understanding), it becomes a little easier to understand once you see the microphone and how it’s used.

The XLR connection for the mic is at the base of the handle, so the mic needs to be hand-held. Notice, though, that the business end of the mic is covered by two screen filters: There’s an oval filter across the front of the mic and a second filter, this one rectangular, that covers the top of the mic and protrudes from the front of the mic by about 1/2″ with a rounded, concave leading edge.

The purpose of this leading edge is that the speaker is supposed to rest this up against his or her upper lip. Yes, the mic is actually designed to touch your face while you’re speaking, which seems odd compared to the use of most mics, but doesn’t really create as much of an issue as it might seem like it would just by reading about it. This funky usage style has led to the 4104 being called “The Lip Mic” by some.

And I have to say, the mic works really well. It seems to have a pretty flat sound, which to me means that it doesn’t add much in the way of presence or brightness… it just reproduces what the speaker sounds like. And it picks up very little, if anything else. The Coles product literature for the 4104 claims that it can be used outdoors in winds up to 20mph with no noticeable decrease in the vocal quality of the user. That is pretty darn cool.

Do a little research on the mic and you’ll see it’s been used to record at sporting events, in big crowds, during hurricanes, in taxi cabs and in plenty of other environments where an ordinary mic would require the voice talent to shout just to be heard.The 4104 sells for about $650 – $700 and would seem to be a good mic to investigate if you frequently find the need to record in loud places or spaces that haven’t been acoustically treated.

The official product page for the 4104 can be found here.

Source: Lou Zucaro’s Blog