Shotgun Mic Shock Mount Isolation In Action

Isolating a microphone can solve issues with rumble or transmitted sounds. The impact can be subtle – a light, steady thrum of low frequency noise, or clear – footfall or movement from another person (or pet!) vibrating directly into the microphone. A shock mount decouples the microphone from the rest of your recording space. This provides isolation to your mic, which will make you get better VO recordings.

Recently, I rerigged one of my microphones, finally taking the time to isolate it more completely from the potential vibrations which can impact recordings.

To be honest, it had not been a super high priority task. That particular microphone – a Sennheiser MKH416 – seemed fairly well protected from transmitted sounds. But, it got me thinking a bit about microphone isolation as a component of quality audio. Two constant challenges are (1) Rumble and (2) Transmitted noises.

Rumble and Transmitted Sounds in the VO Studio

Rumble is always an acoustic issue in most recording spaces. It is the sound of the world, occurring at a frequency low enough that we don’t really “hear” it with our ears. These are the low pitched (below 50-60 Hertz) noises occurring all around us.

Most commonly, it’s the percussive sounds which easily transmit through the frame of your structure, through the mic stand and into the microphone. These differ from the audible “environmental” sounds in that they are traveling through the studs in your walls rather than the air in your room.

To address these two issues, either you isolate the room (a common practice in full studio construction – which most of us don’t have the luxury to do), or you isolate the microphone.

A shock mount enables you to isolate a voiceover microphone from rumble and structure-transmitted noises.

A Shock Mount Isolates your Voiceover Mic

Most microphones come with some sort of suspension mount – often a spider-webby structure with springy elastic bits. These are referred to as “shock mounts” – they are designed to prevent vibrations from traveling into the body of the microphone, where the mic diaphragm might convert it into sound captured in the audio signal. The two above show a couple of approaches (on the left is the tank-like Vanguard shock mount, on the right a more traditional frame suspended by elastic).

Generally, the more sensitive the microphone, the more important it is to take this step. Handheld “stage” microphones can (ahem) hand-le this, but voiceover mics are all designed to be mounted in a separate stand. If your hand is in contact with any of the commonly used large diaphragm condenser VO mics, we’ll likely hear that contact. If you have ever accidentally bumped the mic while recording, you know what I mean.

Shotgun microphones act a bit more like a handheld mic, in that they are (or should be) designed so that any handling noise is minimized. After all, they were designed as boom mics to record voices on film or tv sets, which means they get moved and positioned while recording.

Theory into practice: Isolation Mount for a Sennheiser MKH416

When I first got the 416, it came with only the clip-type mount. I figured I’d have to replace it, but the only other option I had was a fairly inexpensive shock mount purchased for a different shotgun mic. That one had used two rings and an “X” of elastic band. It barely held the smaller mic in place, and when I tried the Sennheiser in it, the longer dimensions caused the microphone to sag and slowly settle. It never seemed to stay in the same place. I need a microphone to remain positioned correctly, so this was not an appropriate piece of studio gear.

The clip mount kept it in place. So, the clip stayed.

The only problem came when tapping my iPad screen when scrolling on a longer script. That slight finger bump got picked up by the Sennheiser. Not a deal breaker, but not ideal.

Well, it was kind of annoying to edit out for longer projects. That helped me decide that I needed to provide more robust shotgun mic isolation to prevent the audio artifacts from occurring

Installing a Rode SM4-R Suspension Mount on the Shotgun Microphone

I noticed that Rode offered a nice little unit which seemed to be just the ticket. It used the Rycote cradle design which isolates a shotgun mic very effectively, while providing adjustability for proper position. it was not overbuilt, so worked nicely in my space and setup. Rode even included a handy hex driver for the screws.

It built up easily and after a few minor adjustments to correct for the slightly taller height, was in place and working within minutes.

Now, even a clumsy screen tap doesn’t seem to make it into the recordings. Another minor studio issue solved.

Back up and running in just a few minutes! (Since I always get questions about the iPad holder, here’s the link.)

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