The Acoustics of Portable Vocal Booths
In our first article on acoustics we covered the basics. In this article we will look at portable vocal booths in general and our own in particular and see how the principles we learned play into how a portable vocal booth or any recording space is designed and built.
What a good portable vocal booth is not.
Contrary to common belief the main purpose of a portable vocal booth is not to keep out ALL extraneous noise. Why? Because it’s just not possible. Blocking sound from getting through a barrier is called acoustical isolation. But to properly isolate a volume of space requires dense materials and/or lots of space. Think concrete, brick, wallboard and insulated walls. Specialty sound blocking materials can also be used although will also contribute to a heavier booth. Therefore, a booth optimized for isolation is going to be heavy and hardly ideal for traveling. A "portable" vocal booth optimized for noise suppression can easily weigh 25 to 50 pounds. That’s a heavy lug around an airport and will definitely not qualify as carry-on.
Can a portable booth keep out all the noise?
But the additional weight doesn’t help that much as true isolation techniques involve more than just the material used in the walls of the booth. It also involves separating or “decoupling” the treated space from the area around it. This is done by techniques like using air spaces in the walls, floating the floor using springs or other methods and structural framing members in walls and ceilings. Obviously, not adaptable to a portable device.
So, what does a good portable vocal booth do then?
It certainly should keep some external noise out. Our Porta-Booth® Pro even has an included built-in fleece hood for noise reduction a full 360 degrees around the booth for those extra noisy environments. More importantly it shapes and the sound in the booth where your microphone resides taking the echoes and that roomy-boomy sound out of your recording. To a large degree that is done by the inside walls of your booth through the absorption of the projected sound into the booth. But not too much! An NRC at or approaching 1.0 (absorbs 100% of sound) will result in your voice sounding flat or dead. You need to have some ambient reflection to give your voice a sense of presence. Otherwise, you end up with an unnatural sounding recording.
What is the best value in portable vocal booths?
It may not come as a surprise if we tell you that our Porta-Booths encompass the best features for the price. For instance we use pyramid design Auralex StudioFoam® to line the inside of our booths. This is the same foam WhisperRoom chose for the inside of their renowned human sized sound booths. The reasons are pretty obvious. First of all it has an NRC of 0.7 meaning it absorbs 70% of sound and allows 30% to reflect back giving just the right amount of “room presence” in your voice recordings while removing whatever bad acoustics may exist in the room you are recording in. Lasting decades, It also defies the crumbling and other deterioration of acoustic foams found in cheap knock-off booths and likewise has a fire retardant that makes it blow torch safe! (You’ll love this video).
Auralex foam panels are used by professional recording studios around the world (and no, you will not find a blanket in a single one). Other benefits of our Porta-Booths include their light weight yet sturdy construction. To get full details for each of our booths click the links below.
The Porta-Booth Plus
The perfect size & weight for traveling it is the only true professional carry-on portable recording booth. It actually fits in your carry-on bag or optionally get it with its own bag. Click here for details of our Porta-Booth Plus.
The Porta-Booth Pro
Over three times larger than the Porta-Booth Plus yet still only weighs 7 pounds! Comes with its own travel bag. Click here for details of our Porta-Booth Pro.