How To Avoid Ground Loops In Your Home Recording Studio
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In this article I will go over proper ways to wire your home recording studio to avoid ground loops, which can cause noise in your audio signal. I highly recommend you start with another one of my videos before reading this article as they build upon one another: https://youtu.be/itY4bpd_5JQ?si=emj9uZMWqppCN14Q
1) Proper Home Recording Studio Grounding
Grounding is the use of a specific wire that will send excess current directly into the ground of the earth. This is a safety precaution and every electrical system to code should have a grounding system.
In home recording studios we want each individual ground to connect to the main ground in the building structure without sharing common grounds with each other. What does this mean?
Imagine you have an outlet where your amp is plugged into and the amp has a three prong plug with a ground. Now imagine in that same room you have a lamp with a three prong plug with a ground as well. Ideally, each of those grounds would not be connected and they would run seperate grounds to the main panel without sharing a common ground wire. Here are two diagrams showing the wrong way and the right way to ground your audio equipment.
The Wrong Way -
The right way:
Notice how in the right way diagram all the audio units go directly from the outlet to their dedicated spot on the electrical panel. These means ground are not shared with additional plugs in your electrical system.
Now, is this doable in all home recording studios, maybe not, but it is the best practice. With everything related to electrical I always recommend talking what you learn to your electrician and discussing options with them. The more you know the more you can teach them about how electrical power interacts with audio.
2) Avoiding Ground Loops
A ground loop occurs when electricity mixes with the audio signal in a shared ground creating a circuit or loop which leads to hums and noise in the audio chain. Now, everyone has different methods for avoiding ground loops. Philip Newell states you should not have interconnected grounds at all, but the feasibility of this may be difficult in the home studio. Rod Gervais, another studio designer says there are two options.
1) Remove one of the ground paths which would create a single point ground and close the loop.
2) Or use an isolation transformer to "break the ground loop." Gervais talks about a unit called Tripp Lite that can be used to eliminate ground loops. (Gervais, 121)
Gervais also recommends asking your electrician if you can install hospital grade isolated ground receptacles and a star grounding system. (Gervais, 122) The idea behind this wiring technique is to run isolated grounds from each electrical outlet that are then connected to the buildings own earth ground. The point is to know enough to ask your electrician if they are familiar with this system, but not to try and install it yourself.
3) The Zero Loop Area Method
Neil A. Muncy coined the term "Zero Loop Area" as a way to stop ground loops from happening. His approach is to wire the studio in such a way that "loop areas" cannot happen. So now how do you do this.
J.H. Brandt wrote a great paper summarizing Muncy's ideas. The best way to understand the zero loop area is to first understand the loop area.
Imagine you have a tube mic that is plugged into a wall outlet because it needs power. That tube mic also must have an XLR cable (with a ground) that is connected to your audio interface or console. The electricity from both grounds form a loop from the console ground to the tube mic power supply ground connected by the electrical supply. Here is a diagram that will visually show this in more detail.
So how do we fix the loop? The best way to prevent ground loops is to have all of your audio gear plugged into dedicated audio outlets behind your desk or if it is a live room at one dedicated location in the room. This way you eliminate the loop that is formed from multiple outlets in the room connected by multiple ground wires. Here is a diagram of the zero loop system in place.
Notice how all the audio gear is plugged into the 4 gang outlet behind the console/interface. That outlet or outlets is then fed directly to the electrical panel. As a bonus your audio should have it's own dedicated breaker(s) on the electrical panel and should only be on one "leg" of the panel. Again, watch my other video mentioned at the top of this article to understand how electrical panels work.
Conclusion
The goal in wiring your home recording studio is to have all your audio equipment on isolated ground that go directly to the electrical panel. You do not want to create physical loops where audio equipment is plugged into outlets around the room and then the audio cables are grounded to a different outlet at the front of the room.
If a ground loop needs to be fixed you can try an isolation transformer. However, when designing your studio it is best to work with your electrician to avoid having ground loops in the first place. Use these tips to ensure your studio has clean audio and clean electrical.
Works Cited:
Brandt, John. Grounding, Audio Wiring, and Zero Loop Area Design. https://jhbrandt.net/wp-content/uploads/2022/11/Grounding-Wiring-Zero-Loop-Area.pdf
Gervais, Rod. Home Recording Studio: Build It Like The Pros. 2nd Edition, Course Technology Cengage Learning, 2011.
Philip Richard Newell. Recording Studio Design. New York ; London, Routledge, Taylor & Francis Group, 2017.
