Many customers get in touch with us asking why they hear a white noise or a hissing sound when they turn up the gain when nothing is plugged into their Scarlett interface and directly monitor the inputs. In nearly all cases this is the noise floor that you are hearing and is normal behaviour.
All interfaces will have a noise floor, as all electronic components generate noise. The noise floor is the sum of the noise each component generates.
When you turn the gain up on the Scarlett, you are adding gain to the input signal, but also adding gain to the noise floor. You'll start to hear noise after roughly 12 o'clock on the Scarlett interfaces. This noise will disappear as you turn the gain back to nothing.
Noise is louder when there is nothing plugged into the Scarlett, as you're amplifying static as well as the noise floor.
For a truer representation of the noise floor alone, you need to terminate the input. This is usually done with an XLR terminator, but you can do this yourself.
- Plug a condenser microphone into one of the inputs.
- Turn off (or leave off) phantom power (48V).
- Adjusting the gain on that channel only.
You'll hear the noise floor without any static interference, and it should be a lot lower in volume. This is a truer representation of the noise floor.
If you find that you are constantly battling the noise floor in your own recordings this would suggest that the recording technique is not quite right for the application. Either the microphone you're using is the wrong type of microphone for the application, or perhaps you are recording an instrument-level signal into a line-level input.
Of course, if you do feel that what you are getting is a fault with the preamp we would recommend getting in touch with us directly. Please provide audio examples so that we can listen to them and advise on the best course of action.
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