Why is mastering an important part of the process?
Well, I'm a mastering engineer. I've been mastering for 25 years. It was always quite a big part of the process where it was a transfer service.
Mastering has changed quite a lot in the last 10 years. Before, you would have your mix that was done on tape, and then you would be working out how to get it onto the format, which would be vinyl or CD. These days, it's turned into a much more creative process because a lot of people are working from home. They're not working in big studios anymore.
I've seen that progression change these last 25 years, and although it's a creative thing, I always think that you should try to keep the integrity of the mix. An external mastering engineer can help by giving you another set of ears. They can't work out whether your mix is any good or not, but they can tell if it needs any tweaking before it's finalised.
Because they're listening to tracks – just as stereo information, and not listening to the individual instruments – they have a keen sense for when it's too bright or bassy during the finishing process.
It's mostly just quality control: making sure the mix is delivered without error to record labels, Spotify, and the like.
But I find that in most cases I can get things sounding much better than what someone's tried to do by themselves. Most times, they want to keep it as is because that's how they like it and they're used to it. But that doesn't mean it's good, or that you can't take it further. What I do is look at it from a different place and take it somewhere else for them. Because of that, "Oh god, I didn't realise it could go there" is a phrase I hear often enough.
If you think you can do it yourself, do that. But it's relatively cheap these days to get people to master your tracks anyway, and there's a lot out there since people do it from home. Having a professional giving you feedback is obviously the best way to go.
Try it yourself, but always try somebody else. Build a relationship with somebody and make them part of your team. It’s a great thing because it means you've got someone outside who will give you feedback on your music.