"Explain Like I'm 5": Balanced vs. Unbalanced Connections July 11, 2013 12:30 8 Comments
This podcast marks the first of a new series in which I attempt to explain complex audio subjects so that a 5-year-old could understand them.
In this first "Explain Like I'm 5" podcast, I tackle the important subject of balancing. What is the difference between balanced and unbalanced connections? How does balancing work? Why do we need balanced connections?
In less than 15 minutes, I answer these questions the way I wish someone had for me: assuming no electronics knowledge, sticking to the basics, and using only terminology that a musician would understand.
Download the mp3 or subscribe via iTunes
In order, I discuss:
- What are balanced and unbalanced connections?
- How can I identify the difference?
- Why are there these two types of connections in the studio?
- How does balancing reduce noise?
- What is Common Mode Rejection Ratio (CMRR)?
- If balanced connections are so great, why isn't everything balanced?
Comments
Noel Casiano on November 12, 2014 18:05
I’ve always just thought of a DI box as a way to lower signal level to appropriate levels for preamps. But you also mentioned that a DI box turns an unbalanced connection into a balanced connection. How does this happen and is it different between how it happens in a passive vs an active DI box?
Peterson Goodwyn on November 12, 2014 18:05
Hi Noel, great question which gets to some of the complexities about balancing I glossed over in the podcast. “Balanced” is used these days colloquially to mean two different types of circuitry: balanced and differential. I left this distinction out of the podcast because it belongs in the “black box” of electronics which you now want to open!
It just so happens that passive and active DIs present perfect examples of these two different kinds of balancing. A passive DI uses a transformer to provide a balanced output—one where the hot and cold wires have the same “balanced” impedance. An active DI, on the other hand, creates identical inverted and non-inverted signals and sends these to the output. This is what’s meant by “differential” circuitry and what I was talking about in the podcast with difference amplifiers.
Nigel Thompson on November 12, 2014 18:05
This is a great idea Peterson … thank you vey much in advance.
Steve on November 12, 2014 18:05
First off, I gotta give up some kudos, great website. My band built a reamp box from your schematic and it works great. The only thing else I would mention is how the stereo interacts with the TRS. I believe the tip is left channel is on the tip, and the right channel is typically on the ring, correct? Maybe a separate podcast for mono versus stereo, with stuff like pulling the headphone out halfway out to get a mono cable work in a pinch.
Stephan on November 12, 2014 18:05
Just to make sure. The 2-/3-pin rule only applies to mono signal connections. Stereo connection, e.g. headphones, will have TRS but are not balanced. I know I am stating the obvious, but just making sure…
Peterson Goodwyn on November 12, 2014 18:05
Yep! Good clarification.
Dan on November 12, 2014 18:05
On the subject of subreddits…
Is there a DIY audio subreddit?
Ethan on November 12, 2014 18:05
I have a Tascam 388 (unbalanced inputs). Does it not matter that I am running balanced outboard gear such as compressors/pre’s into my inputs? Also on the stereo output I’ve never understood the balanced/unbalanced switch….
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