Audio Studio Build Part 2: Electrical & Low Voltage Wiring for Voiceover Recording Booth
Electrical and Low Voltage Wiring
I wanted to minimize the number of holes and openings that could compromise the soundproofing. The layers of walls have 8 holes - the 4” air intake and exhaust holes being the biggest. We’ll talk more about those later. There is one hole where the heater wire comes in. Before we started all this construction there was a small convection heater under the window. We decided to keep this wire in place. (At the time of this writing I’m still researching silent options to replace the convection heater. I saw the ceramic panels from Home Depot but the reviews said it had a strong smell for months. If anyone has any suggestions please email me or comment.) On the two exterior walls there were already outlets. Rather than pull the wires out I left them there.
There is a hole in the ceiling for the new 14/3 wire which brings 2 dedicated circuits into my studio. Another hole feeds two CAT6e cables into the booth and finally there is a 2” hole for all the audio and HDMI cables - both on the wall with the door.
Minimizing the number of holes made my contractor happy since feeding wires through successive layers of Sonopan and drywall is a bit of a pain. In fact, during construction there was a moment when we almost forgot to pull the heater wire through the Sonopan. Leaving that in there definitely wouldn’t have been to code.
I have many years of experience as a weekend assistant to licensed electricians on summer volunteer projects installing commercial and residential electrical. So surface mount electrical channel and outlets are something I wouldn’t normally want. I like everything to be nice and clean so normally I’d rather cut holes in the drywall to run the wire inside the wall and patch it later. But in my booth I felt surface mount electrical was a good way to avoid making a ton of holes through my double walls and subsequently compromising my soundproofing. That being said, the channels and boxes still need to be screwed into the wall. What’s worse? A bunch of screw holes, or an in-wall electrical box covered in acoustical putty? I haven’t seen any actual research documenting a test of these scenarios but I’m looking out for one.
Acoustical Putty
For all wire holes I used acoustical putty to plug any space around the wires.
I wanted two switch driven outlets on the ceiling to plug my LED lights into, and a few outlets along the wall for monitors and audio devices. I also wanted to run two switch driven outlets to the wall just outside the booth - one for the “on air” recording light to keep my family from disturbing recording sessions, and one for the exhaust fan which lives outside the booth.
Switches
One switch operates the on air light that’s on the outside of the booth. The other switch turns on the air exhaust fan that is also on the outside of the booth.
I put the “on air” outlet closer to the ceiling. I have a custom LED “on air” light that I got on Aliexpress. Love love love it. I sent them the graphic and they etched my design in a piece of glass. The only issue is that it’s powered by a USB block and the black USB wire coming from it steals the show a bit. I tried to cover it with surface channel. It looks ok.
I put the switch driven outlet that powers the air exhaust fan closer to the floor. I put my recording computer outside the booth so I don’t pick up fan noise on my mic. Since I needed an outlet for that computer I split the outlet for the fan. The top plug is powered by a switch inside the booth so I can turn the exhaust fan on and off without exiting. The bottom plug is always live. I plugged a back up battery power supply into that for my computer and harddrives.
Maybe you are wondering about those Cat6e wires. Seems like a bit of overkill? I wanted to future proof my booth. Technology is always changing. Cat6e can be used to move a lot of different signals, so I wanted the wire going through the wall to be useful years later if needed. Even though I have all the tools, I haven’t finished off any low voltage cables in the last 7 years so I decided to just install finished cables. I poked them through staggered 1/2” holes in the wall, meaning the holes don’t line up with each other. That way if sound does leak through them it will hit insulation, and then drywall on the booth exterior. I plugged them into feedthrough wall plates that screw into Legrand surface mount boxes.
Seen here is one of the pre-existing outlets, and the Ethernet feedthrough cables. Once again I smashed acoustical putty in the space around the wire.
For the XLR, 3/4” audio, USB and HDMI cable bundle I cut a 2” hole in the corner of the wall. I bought a 1 gang cable plate for wire management but it was too small for the number of wires I ran to my booth. I thought about running a tube from the inside to the outside of the booth. This would have allowed me to re-pull the wires if I ever needed to…but I felt this would compromise the soundproofing too much. I chose instead to purchase a 2” electrical pvc conduit 90 degree connector and cut off two pieces. I used these only to clean up the entry of the wires through the drywall. I used one for the hole inside the booth and the other for the hole outside the booth. Looking back I should have just installed a tube and built something around it to insulate sound leaks!
Audio, Video and Computer Wires
The wire bundle features XLR, 3/4” audio, USB and HDMI cables.
For now I’m using the following:
HDMI cable to mirror the computer screen
USB from the audio interface to the computer
USB from the computer to a dongle that links to the wireless keyboard and mouse
Currently I’m trying out powerline ethernet adapters for the internet. This is a crazy technology I do not yet understand that sends the internet through the house electrical system. What will they think of next. If I have problems with this for my Source Connect I can hardwire the internet from my router through the Cat63 wallplates.
Extra wires I ran just in case:
Cat6e
Backup HDMI
2x XLR - one with female in the booth and one with male in the booth
2 extra USB - one female end in the booth, one male end in the booth
2x 3/4” audio
2x 1/4” audio
Wire Entry Point
The wire entry point is opposite to the place I stand to do voiceovers. This means that the back of the microphone will cancel any noise that sneaks past the acoustical putty. Here you see the ethernet feedthrough wall box, the pre-existing outlet with the powerline ethernet adaptor, and a new outlet for the additional circuits. I installed 2 hooks for cable management adjacent to the A/V wire entry.
In the booth I connect my TLM-100 to the audio interface using a 15’ XLR cable. I put 4 outlets along the wall in the booth, 2 for each circuit.