Volume Matching and Master Recording Evaluation
Howdy! Here’s an in-depth article on why volume matching is a great way to more accurately evaluate your masters, and how to do this at home.
Before we begin, please note: if we’re working on a project together, I will always make a master as loud or as soft as you would like it. If you’d like to hear something louder, just ask! It’s your music and your call, always.
But, I will also always tell you when we might be getting to a point where high levels of loudness might not be in your best interest for a given playback medium, so you can make an informed choice. With that, here’s some more details!
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Human hearing is incredibly sensitive and is fully integrated with the rest of our bodily systems. If you’ve ever heard a very loud and sharp sound, such as a gunshot, you might notice that it can immediately invoke a quite drastic and automatic response, usually one or more of the following:
Reflexively looking for the source of the sound
Eyes widening
A sharp and quick inhale
Muscle tension, jumping, or reflexively crouching
Heart rate increasing
Immediate feelings of apprehension or fear
These responses are evolutionary, and are designed to keep us alive in the wild where dangerous predators could kill us. They are still with us today, even though being hunted by a saber toothed tiger isn’t really an issue anymore.
A similar set of automatic responses takes place when we’re listening to music: the louder the music gets, the more our heart rate increases and the greater feelings of excitement we sometimes experience. This is probably a good thing (in moderation) at a live concert, but it can be a real problem when evaluating a master, because these automatic excitement responses mean it’s always easy to confuse a louder sound with a better sound.
Complicating things, human hearing is not linear, meaning your hearing changes when listening at different volumes. The louder something sounds, the more it will appear to be thicker, bassier, and punchier. Since these are often desirable traits in certain styles of music, this once again means it’s easier to confuse louder with better. This is also the reason why I suggest checking your master at both loud and soft volumes.
Complicating things further, different playback mediums (streaming, vinyl, tape, CD, etc) all have different ideal volume levels, i.e. levels at which the medium will show your music at its best. Streaming platforms in particular favor more dynamic music, which is a good thing, but this means that if you choose a master that is too loud it will actually sound worse when played back through a streaming service. Most streaming services have algorithms on the backend that adjust the overall loudness of your music upon submission-this is called loudness normalization. If you submit a really loud master, that volume will just be turned right back down in submission processing. But, in doing so, this will introduce distortions and artifacts that will make your music sound thinner, tinnier, squashed, less thick, and less punchy-often undesirable traits.
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It isn’t uncommon for a musician to approve a very loud sounding master, only to be surprised when it doesn’t sound nearly as good as they remember after it’s released on a streaming service. This isn’t the fault of the streaming service necessarily, but it could be the fault of a mastering engineer who might not fully understand how modern streaming services work. This is a particularly challenging line to walk for the mastering engineer in styles of music that are intentionally meant to be experienced quite loud, such as metal, grindcore, etc. When in doubt, just talk to your mastering engineer and ask how they approach the issue of loudness normalization on streaming services.
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Mastering engineers compensate for all these different effects by using volume matching at all points during the mastering process. However, it’s equally important for the artist to consider, because you’re the one who has the final call on approval of the master, and you want your evaluation to be accurate.
Volume matching means making sure that different audio is being played back at the same apparent volume when making a direct comparison-this will prevent you from confusing louder with better. If you have different masters from different engineers, they will sometimes be slightly different in volume upon delivery. When listening to each master, make sure that each version is being played back at the same apparent volume when comparing. If one of the masters is a bit softer then the other, just turn it up a little to match the louder one, before you make an evaluation, and vice versa. You can do this by ear and working the volume knob during playback; just get it sounding close, no need to get too fancy here. This is a simple step, but I think you’ll be surprised at how much of a difference it makes in making your master evaluations faster and more accurate.
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You can also use volume matching when mixing or recording. Next time you get excited about slamming the knobs on that compressor (or any other tool that impacts how loud something appears), try volume matching the input and output gain on the compressor by ear, and set your makeup gain to zero, before messing with things like threshold, attack, and ratio. This will clearly tell you when you’ve compressed material in a positive way versus going too far. You are the final judge as to what “positive compression” and “too much compression” means for your music. There is an entire field of study called psychoacoustics which deals with how our brains interpret sound, and how that connects with the physics of sound in the natural world, if you're looking to go deeper on this subject.
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If you’re interested in learning more about DIY music-making and engineering concepts, I’ve written a book on this subject focused towards the DIY musician, and it’s available right here. You’re also welcome to contact me directly or book a coaching-I’m here to help!
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If you're into practical studio tips in a medium and short format, I’m doing a lot more of that over in my educational space, DIY Music Guide! We’ve got a Patreon feed for additional content of this type.
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