Supplying audio files in compressed formats or applying heavy limiting or compression during mix down can compromise your master and negatively impact your audio mastering results.
Having your album professionally mastered is one step you can take to bring your mixes from “pretty darn good” to “ready for radio.” A mastering engineer can raise the overall volume of your mixes, correct minor EQ imbalances, bring consistency to an album, and clean-up the hiss and pops that may have snuck into your recording – but there’s a lot you can do to make the process go smoothly and stress-free.
Sending your masters to a mastering house in the wrong format, or with issues that cannot be easily dealt with by a mastering engineer, can lead to frustration and poor results. The team of engineers in The SoundLAB at Disc Makers master over 2,000 albums and singles each year – we’ve pretty much seen and heard it all. Here are two common issues you can easily avoid when preparing your mixes to be professionally mastered to help ensure you get the best results.
You’ve worked hard on your recording and mixing, hopefully keeping the performance and recording quality as high as possible throughout the process. Typically that means a 24-bit resolution at a sample rate of 44.1K or higher. Lossy formats like MP3, AAC (the format iTunes uses), and WMA (Windows Media Audio) may be a quick and easy way to share versions of rough mixes with members of your group or producers, but don’t make the mistake of submitting these files for your mastering session. Make sure the files you send off for mastering are high-quality WAV or AIFF files that are kept at the same bit depth and sample rate at which the project was recorded and mixed.
The problem with those lossy formats is they trade a small, portable file size, for overall quality, detail, and resolution. At lower bit-rates, fairly dramatic changes to the audio can occur, such as harshness in the higher frequencies and artifacts from the encoding process. Another common side-effect of a low bit-rate or lossy format is a “swirling” sound that often turns crisp high frequency instruments like cymbals into a less detailed wash of sound.
Presented with these types of files, a mastering engineer may need to make drastically different decisions during the session, and may spend more time compensating for the deficiencies of the submitted file type than actually working on enhancing your mixes – and that’s not what you want to spend your money on. If you submit these types of files, expect a call from your mastering engineer asking for higher quality versions.
And keep in mind, when your fans rip your CDs to a compressed format, or you upload your tracks for sale online, your music will be compressed again. That’s more musical information and detail being lost!
Our preferred file type here in The SoundLAB is a 24-bit, stereo interleaved file – at the same sample rate your project was recorded at.
Avoid applying heavy limiting or compression during mix down
Another common issue we see with files submitted for mastering is the over-use of compression or limiting on the stereo buss during mix down. Compressors and limiters are two useful mastering tools that are often used to increase the overall volume, or loudness, of a recording. However, limiting or compressing the entire mix prior to mastering can cause major problems in post production.
Often artists want to hear a quick version of their mixes louder and more “pumped up” during the mixing session, to get a feel for how they’ll stack up against other recordings. What many artists don’t understand is the final volume they hear on those major label recordings is usually the result of work done in the mastering session, not during mixing. These quickly “pseudo-mastered” mixes we hear often have audible issues, such as distortion from the improper use of a limiter or a “pumping” effect from misuse of a compressor. These issues cannot be corrected by a mastering engineer and will result in a call asking you for the versions of the mixes without those effects applied. (Hopefully you have them!)
That final, competitive volume and punchy sound you’re looking for will be achieved by the mastering engineer, using the proper tools and techniques, and done in a way that preserves as much of the dynamic punch and feel of the original mixes as possible. For example, a good mastering engineer might use a few separate stages of compression or limiting to arrive at the final mastered level you hear. Different compressors, with different threshold and attack settings, placed in certain spots of the mastering chain (pre vs. post EQ for instance) are often necessary to boost the volume of a mix, while avoiding the issues mentioned above. Trying to approximate these results using a single limiter, or one of the many “volume maximizer” plug-ins available, is often futile.
Compression and limiting are usually necessary on individual tracks, particularly the bass and vocals, to smooth those elements out and help them better fit into the overall mix – but leave them off the final stereo mix down, or use them sparingly. You’re paying a mastering engineer to do the work, so let them take care of that part of the process with their tools and expertise!
Brian Lipski is the manager of The SoundLAB at Disc Makers, and has been a mastering engineer there for over 20 years. He has personally mastered thousands of releases in his time at The SoundLAB.
Audio Mastering – The Mysterious Post-Production Art Form
Audio mastering basics for your home studio
Audio mastering for vinyl
From mastering audio to manufacturing: the steps in CD production
Mastering Gear Overview