Mar 6, 2014

Building a Vocal Booth

One day I found myself in Staples in the Poster board aisle so…

I bought a standard Foam Staples brand poster board. After experimenting with some cheap cardboard to find an optimal height that worked with my boom arm, I cut it down to 15 inches in height. The standard poster board is tri-fold. I wanted four folds so I carefully scored the central panel in the middle, being careful not to cut all the way through.

There’s lots of acoustic foam out there, all of it seems overpriced. I purchased the Sonic Homework Acoustic Sound Foam Kit from Amazon. It’s 8 sq ft of foam and you can see I had enough for all four panels. with two left over pieces the size of what you see draped across the top in the picture. In the bottom I just fold it in half and put it underneath the microphone. My “kit” did not come with any adhesive like it was supposed to, so I just used some household glue (sorry but I can’t remember exactly which type but I think it was just Gorilla glue).  I also aligned all the foam wedges vertically because that allowed the least resistance when closing the booth around the microphone and I didn’t have to leave any gaps at the seams.

I then put some Velcro strips on the front sides and I just use a Velcro strap to tighten up the opening so there is very little wood on the bottom exposed while recording. The image below shows the booth with the strap not attached. This idea came from several sources on the internet where people built this kind of booth in a box. I just needed a version with the top open so that my adjustable boom could be lowered inside and removed at will.

Results

The difference is not huge but it is noticeable.  I also have plantation shutters directly behind the mic co I usually have those at an angle to avoid direct reflection. Like all things audio, how much this may or may not benefit you, depends on many factors including your voice and the acoustics of your room. If you hear a lot of room reflectivity you’ll probably gain a lot of benefit.  I was recording in a room with hard walls and floors. I do light noise removal and then compression and EQ adjustment. Adding the foam didn’t allow me to eliminate those steps but the end result is a warmer more appealing sound. Plus it’s a heck of a lot cheaper and takes up less room  than a full sound isolation booth. Once my new Pluralsight course on the Qt C++ Framework is published (May 2014 or earlier) you’ll be able to hear the difference for yourself.

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Update One Year+ Later

I’m still using the booth but I’ve discovered a couple of things I’d like to share.

  1. I should mention I record audio separately from my videos when doing a demo. Doing both at the same time would be a little awkward with this setup. 
  2. I used to just read my scripts from OneNote on my second computer monitor (off-screen). This required turning my head so I wasn’t speaking directly into the microphone, this makes your volume change a decent amount if you turn your head and start talking directly into the mic for any adlibs.
  3. VocalBoothWithIPhoneI recently switched to using OneNote online which syncs with my iPhone. Now it’s much more convenient. I can hold my iPhone inside the booth and you use it as a manually scrolling teleprompter.  This both allows me to talk directly into the microphone and it tends to position me automatically in the same position each time.
  4. One problem you have to know about is cell phone noise. Luckily the first time it happened I immediately knew what it was because I used to hear it all the time in my band when someone put a phone too close to a mic’d amplifier. When your cell phone goes to ping the tower it creates a very audible noise signal when it’s this close to a mic. It doesn’t happen constantly but still who wants to deal with that? The answer is pretty straight forward. Put your phone in Airplane mode and then manually turn on WiFi. Very easy to do in my iPhone. I don’t really need cell phone coverage, and in fact don’t want the phone ringing, while I’m recording. I do want to be able to update the script online and have it show up on the phone. Of course when you leave the house (something else I almost never do), you have to remember to restore your cell coverage.

(If you can’t hear the noise in the above sample, here’s a link to one with the volume normalized to 0 dB, you might want to turn down your volume before starting and turn it up as it plays.)

 

About Me

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Tod Gentille (@todgentille) is now a Curriculum Director for Pluralsight. He's been programming professionally since well before you were born and was a software consultant for most of his career. He's also a father, husband, drummer, and windsurfer. He wants to be a guitar player but he just hasn't got the chops for it.