How Do Microphone Isolation Shields Work?

In order to cater to the most audiophile audiences, modern-day home studios worth their salt are beginning to resemble professional studios of the past more with each passing day, especially if we judge by the amount of equipment they’re being furnished with. Among these pieces of equipment, you’ll usually find a curved panel and acoustic foam balls surrounding the microphone.

This portable panel is called a “microphone isolation shield.” But what does it do, exactly? Stick with us as we’ll attempt to give a comprehensive explanation of this device’s purpose within the context of audio recordings.

How Do Microphone Isolation Shields Work?

Microphone isolation shields (also named “portable booths” or “portable acoustic screens”) operate on the same basis as any other soundproofing gear. They’re made of a very dense but porous and uneven material capable of absorbing sound wave reflections, along with all the annoying harmonics these reflections are prone to producing.

They nearly accomplish the same goal as a soundproofed booth and are currently heralded as more cost-effective noise-reduction alternatives to the latter. What’s more, whereas room soundproofing is aimed at muting noise from the outside, microphone shields address reverb generated from hard surfaces located inside closed doors as well as noise coming from nearby electrical gadgetry, so they’re handy even in sound-insulated areas.

How Are Microphone Isolation Shields Built?

In most instances, this shield is composed of a type of foam or foam-like padding fitted on a curved outer shell – made of a more rigid material (e.g., aluminum, steel, plastic, etc.) – forming a semi-circle. This shape enables it to trap outwardly-expanding soundwaves while the tougher material that holds the foam strengthens its absorption capabilities, making it capable of soaking up reverb signals and unwanted noise more evenly.

The foamy material is usually cut into wedge or pyramid shapes in order to handle vibrations better, similar to how a stationary soundproofing panel works.

Depending on how you prefer to record (sitting down on a desktop or standing), you could find isolation shields coupled with tall structures akin to microphone stands or smaller tripods.

As a side note, to ensure better results, you ought to place your shield at a fair distance from the microphone without moving it too far away. It should be far enough to avoid any pop sounds and close enough to get a more resounding recording without needing to increase your microphone’s gain and, hence, make its self-noise more perceptible.

Benefits and Practical Uses of a Microphone Isolation Shield

The most notable advantages can be broken down as follows:

1. More Clarity

If you’re a podcaster or voice actor, especially a professional one, you can definitely appreciate the enhancements in clarity that a good-quality recording setup brings to your audio tracks.

At times, you can sift out unwanted sounds with the aid of software noise-elimination tools, but these still can’t completely replace their hardware counterparts because you risk losing a great portion of your audio’s fidelity. There’s only so much that a good DAW can do, but at some point, you’ll need some manner of physical reinforcement.

You may be able to discern this for yourself. For demonstrative purposes, try recording a sample with an isolation shield installed and compare it with one recorded without it but with software noise-reduction applied instead. The distinctions should be readily noticeable upon first listen.

2. More Affordable than Regular Soundproofing

To illustrate this point, let’s compare some numbers:

  • Soundproofing: Costs of soundproofing a room can vary significantly depending on your room size and the surfaces covered, as well as the material or method used. To give some estimates, insulation work can range from $150 to $2,000. If you wish to do your own calculations, you could multiply the square footage of your room by the square foot pricing, which oscillates between $1.50 and $5.00.
  • Isolation shields: These can be bought for as cheap as $15, with some of the most expensive models costing around $65-$70 (usually packaged with a stand and pop filter).

Hence, judging from the data we just outlined, you could expect to save from a minimum of $80 to three- or even four-digit amounts in many cases.

3. Ideal for Travelling Voice Workers

In the wake of digital nomadism and remote work, many podcasters and voice actors have the flexibility of taking their work with them wherever they go. With the aid of a portable acoustic shield, they can put out moderately high-quality material regardless of where they’re stationed, provided that there are no overwhelming outdoor sounds leaking into the room.

Dispelling Some Myths

Despite all the benefits we have just described, we should clarify that:

  • These shields are not – and were never meant to be– a replacement for soundproofed rooms, so you should not expect the exact same returns in each case. In fact, a shield won’t be capable of eliminating every environmental sound if you live in a relatively noisy area (though it could still reduce some harsh frequencies.) Case in point, a “fixed” sound booth will dampen noise by 30dB, dwarfing the 1.5dB reduction achieved by its portable counterparts.
  • They might not do much in large, open environments since distant signals and echoes will eventually find their way into the microphone regardless of what’s placed in front of it.
  • Adding to the above, a premium mic isolation shield has the potential to suppress 80% of reverb and echo, which, while still impressive in its own right, doesn’t match the standard results obtained in a regular recording booth.
  • Some professional microphone models pick up very low background noise, effectively rendering moot the usage of an acoustic screen. Examples of microphones of this kind include the Newmann TLM 103 MT, the Sennheiser Professional MKE 600 Shotgun, and the Shure MV7 USB Microphone.
  • Some rooms can have exceptionally optimal acoustics even without sound insulation installed, making the use of a mic isolation shield overly redundant. To test this, you could borrow one from a friend or acquaintance and record two samples, one of them using the shield. If you find no discernible differences between both tracks, then that means you could do perfectly without one.

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