Here’s the situation: You, as a mastering engineer, just completed mastering a few songs for a new independent artist, and they love your work. Excellent job! Now they’ve asked for a few deliverables. First they would like copies of the songs for upload to all the streaming services. Second, they would like a copy of each song for their music videos, which will wind up on YouTube. Third, they would like to manufacture a couple hundred CDs to sell during their upcoming tour and also give away to their crowdfunding supporters. Your job, since you’ve gotten this far, is to create versions of the masters that are suitable for each of the above uses. Let’s examine each case to see what’s really needed.
Compression vs. Compression When recording, mixing and mastering music we apply dynamic compression, which is a way to musically control dynamic and tone. During lossy encoding, like mp3 or AAC, data compression is applied, which reduces physical files size. For this article, compression refers only to data compression.
YouTube and Streaming Video
Audio for video is probably the simplest case, so let’s get to that first. For video, you should deliver a 16bit, 48kHz .wav file version of your master and include instructions to the video editor to encode the audio as PCM, uncompressed audio. Every video editing workstation is different, but the editor needs to choose an export option, or codec, that embeds uncompressed PCM audio into with the video file. Do not let them export using a lossy AAC or mp3 codec.
When the high-resolution video with PCM audio gets streamed via YouTube (or other streaming services) the highest resolution playback setting should stream uncompressed audio and video. If the user chooses a lower quality playback setting, YouTube will stream a more compressed, lower bitrate and lower quality video and audio file. If your original video file contains an already lossy file, it will be transcoded again for lower bitrate streaming, so the viewer hears an audio track that has been twice damaged by lossy encoding. Demand that video editors keep this in mind! I have personally spent a bit of time learning the encoding options of a few common video editing programs so that I can gently offer some suggestions to a video editor as to what encoding format may be best for a given situation.
Headroom and Lossy Encoding. You should be aware that creating a lossy-encoded version (mp3 or AAC) of a music file will introduce some distortion, and thereby raise the volume of the audio file by a little bit. A 320 kbps mp3 may raise the volume by 0.5 dB, while a 128 kbps mp3 may raise the volume by as much as 1.5 or 2 dB. Knowing this, it is important to maintain a ceiling of at least 1.0 dB (True Peak) for your mastering maximizer/limiter when exporting for lossy encoding, which includes mp3, AAC and use in streaming videos.
Optimize for Online Distribution
Streaming and download are the two most likely ways your music will be distributed online. In most cases, your music will be available for streaming on services like Spotify, Apple Music, Tidal, Deezer, etc. For purchased music, you will most likely use a service like iTunes, Amazon Music, 7Digital, eMusic, BandCamp, etc. For those of us who are not signed to a major record label, we must use aggregators, like Tunecore, Distrokid, to submit our music to streaming and sales platforms. While most aggregators allow you to upload almost any version of your song (mp3, .wav, flac, etc.), it’s best to provide a version that will play well on all the sites.
Each streaming site measures the loudness (LUFS) of your song and matches your song’s level to that of all the songs on the platform. In order to avoid processing your audio, most songs are simply lowered in level to meet a specific LUFS measurement. However, not all services use the same LUFS standard and not all sites measure loudness the same way. So what are we to do? For better or worse, we don’t have much of a choice here. When using aggregators, we are able to provide one master that gets distributed to all the platforms. But really, that’s okay as long as our master is competitive with other songs in our specific genre. Everyone’s song will be treated the same way on each platform, so the playing field stays level.
Optimize for iTunes
The iTunes store is an exception to the above description. iTunes will currently accept MFiT (Mastered For iTunes) masters from independent artists via Distrokid. The deal with MFiT is that an MFiT certified mastering engineer will provide iTunes with a 24 or 32 bit .wav file. MFiT also specifies that you leave some headroom for mp3 encoding. To become certified in creating MFiT masters, take some time to read and understand the Mastered for iTunes guide from Apple.
Mastering Plugin Resources
It is important to know exactly how a particular lossy encoding or streaming platform will change the level and sound of your master. To that end, the following products allow you to audition your master in various encoded formats to check for loudness problems on many platforms:
CDs, Vinyl and Online HD
While it’s becoming less and less common for independent artists to manufacture and sell CDs, the idea may still appeal to many, especially those of you who play live shows or have an audiophile audience. When preparing to manufacture CDs, make sure to print the final master at 16bit, 44.1 kHz. If you intend to press vinyl, contact the pressing plant or cutting room to see if they would prefer an unmastered or a 24 bit file instead of the 16 bit CD master. Vinyl cutting often works better from a master that hasn’t already been maximized for CD.
If you are pressing compact discs, be sure to check with your CD plant to see if they require a Red Book audio CD, disk image file or a special DDP file for duplicating or replicating your CDs. The plant will also need your artwork delivered in a specific format, so make sure to get that info before you complete your graphic design elements.
Online sales of uncompressed .wav files seems to be available from only a few sources, like HDTracks, AIX Records, Chesky Records and artist sites like Bandcamp and Soundcloud. These sites will sell the highest resolution version of the music you can provide. Even if you provide uncompressed files to these sites, you should be aware that many listeners will still convert the downloaded files to mp3, so it is still advised to leave 1 dB headroom on your .wav file masters.
It’s a Wrap
DIY distribution has become the norm and it behooves all of us to learn about the best way to create and distribute our masters. The business side of distribution and revenue collection is a vast issue, but creating masters that sound great on all the various platforms and media should become second nature. Remember that as streaming services mature, they may periodically update their delivery recommendations, so do your homework and try to stay on top of the state of things.