If you’ve ever heard the term “Unity Gain” but don’t have much of a clue on what it is exactly – let alone why it’s important – you’re not alone. The core principle behind unity gain is having the input level match the output level in either a single device or a signal chain. In other words, if you have one volt entering the beginning of your chain and you also get one volt out at the end of it, you have “unity gain.” While that might not seem like much, it’s actually pretty important and even critical depending on the application. Read on to find out exactly why.
Gain and Unity Gain
While the term “Gain” itself is fairly ambiguous and can refer to a few different things in the world of electronics, the type of gain we talk about when we look at amps and audio gear is voltage input. This type of gain refers to a device’s ability to take an input signal and bring it up to a higher voltage level. And while similar, gain is not the same as a volume control (read more about their differences in our Volume And Gain article).
As far as unity gain goes, it essentially entails matching the input and output stages between devices to the same level for better signal transfer. If you’re using a mic and a mixing console, for example, the input and output levels of both should all be equal in order to establish unity gain. When all of your devices have been properly matched, you should be able to take out any one of them without affecting the voltage of the signal.
Why Unity Gain Is Important
Whether you’re connecting a pedal to an amp, a mic to a PA system or a DAW to a mixing console, establishing unity gain between these devices will result in an overall stronger, cleaner signal without creating distortion or unwanted artifacts. In microphones, for example, establishing unity gain results in a much fuller sound with more dynamic range and less propensity for feedback.
If you’re recording or mixing live sound, establishing unity gain is an absolute must if you want good results. Sure, it might seem like a tall order when you consider all the different components that go into the equation, but it will ultimately lead to a much cleaner mix and avoid critical feedback and headroom issues. For example, establishing proper unity gain will yield the best gain-before-feedback levels, and the more gain you can get cleanly without unwanted noise or distortion, the better the overall sound will be. Check out the video below for a lesson on establishing unity gain on a PA system.
At this point, you might be wondering about gear specifically made to boost your gain (such as preamps or amps in general) and where they fall into the equation. You should still use them as intended, but by first achieving unity gain, you’ll start off with the best signal possible from which you can boost or cut to your liking. Otherwise, you might be boosting a weaker, diluted signal, not unlike trying to enlarge a picture that has had its original resolution reduced.
Hopefully, the information above has given you a good idea of what unity gain is and why it is important in obtaining the best signal quality possible. While it means a little more work getting your setup ready, it's definitely worth the results. For more tips and other helpful articles, make sure to check out our Musician Resources page by using the link below!
Your Turn to Sound Off!
Did the article above give you a good sense of the idea behind unity gain and why it creates a cleaner signal?