Tech Tutorial: Gain, (and why it isn't a volume knob.) Oct 7, 2017 5:17:40 GMT -8
Post by duffyweber on Oct 7, 2017 5:17:40 GMT -8
Tech Tutorial: Gain, and why it isn't a volume knob.
Another relatively technical tutorial for those of you who want to step up your audio engineering game.
And to step up your game, you need to step up your gain (wait! No... You need to step up your UNDERSTANDING of gain. Stepping up your gain is kinda a problem if you do it too much).
First of all, it's important to know that while turning it up makes your recording "louder," GAIN IS NOT A VOLUME KNOB.
Gain increases the signal power coming from the mic. Volume increases amplitude of an audio wave. What most people don't understand is that the gain setting only functions in the preamp stage and directly changes/amplifies the audio signal BEFORE IT IS RECORDED. Turning gain up at the preamp interface and either keeping main volume the same or lowering it, at the DAW* is how you get clipping, warping and a distorted signal.
*Your recording software
Volume takes your "final signal" and simply makes it louder and louder (without distortion, more or less, provided your equipment can HANDLE it.)
In the case of recording audio, your aim is NOT to get your final volume via the gain on your interface.
Rather, your goal is to set the gain to where the signal arriving in your DAW is at an acceptable level, with clear, detailed audio, regardless of the volume you're speaking.
So how do you calibrate your gain?
First: it is easy to tell if your gain is too loud. If the end product in your DAW looks like someone took a lawnmower and flattened off the top of your waveform, the gain is too loud. Crank it way back.
If it looks like someone just clipped off the tops of the loudest ones, it's STILL too loud. Crank it way back.
If you know how to work a mic, you know that you don't ACTUALLY scream into a mic when "screaming" into a mic. Your goal is to get the top of the waveform to not have any distortion or clipping when you're talking relatively loudly, or "Screaming" into your mic.
Conversely, how to tell if your gain is too LOW:
When you've completed the above, you're going to notice that your lower talking points look... well, very, very TINY in the DAW. This is not a problem, usually, because as we discussed, volume is a separate thing from gain, and amplifying the sound should yield a beautiful, clear, perfectly audible waveform.
Basically if you're recording at normal volume, and the signal LOOKS very low in the DAW, it is probably alright. If you amplify the volume in your DAW after recording, and the sound is strange, and sounds faded, you need to adjust your gain slightly upwards.
If you amplify your sound and the ends of your sentences, or quieter and more subtle sounds within them are faded, inaudible, or sound strange, your gain is too low.
If you noise-reduce your recording, and the hiss from the noise floor is gone from the parts between sentences, but remains behind your words when you speak, your gain is too low. (The noise floor of the mic/interface are too loud compared to the voice and is hard to extricate via digital cleaning tools, in this scenario.)
So there you have it!
Once your gain is set correctly, you can adjust the volume to make it louder or quieter, and easier (or more pleasant) to hear AFTER the recording has captured the sound clearly and accurately.
If the sound lacks presence after you've increased the volume a lot, in some cases, you can do a dynamic compression to richen it up a bit, but that's another tutorial. (Which I just put up here, in fact: voiceacting.boards.net/thread/1433/tech-tutorial-range-compression-downs