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The Complete Guide To Mastering For Compressed Audio Formats

The Complete Guide To Mastering For Compressed Audio Formats

Don’t let the cracks show in your music!

Learn How To Master For Online Streaming Services

The traditional form of music distribution has radically changed over the last 10 years.  No longer do you have the same chain of command from recording studio to mastering house to the pressing plant shipped to the record store.  Although that still exists in an ever diminishing circle the rise of streaming outlets seems to be the way of the future.

Aside the current state of disarray from the new world of compiling music charts from streaming plays (just look at the record breaking, mind boggling numbers from Ed Sheeran’s third album with all 16 tracks that dominated the UK top 20 singles chart, did anyone else get a look in?  One other issue that can cause confusion for artists themselves is ‘what compressed format and level should I be rendering my music too?’.

It’s no myth that mp3 traditionally doesn’t sound as good as higher quality audio formats and that AAC has had it’s issues in the past but they are the best and most widely used formats for distribution and are definitely here to stay.

Of course these formats are a trade off, by reducing the size of your audio it’s easier to distribute to online platforms but the rub is that your audio quality suffers a little.

Think of it like this, if you write a hand written letter.. for those of you as old as me remember that time?  For those of you too young to know what writing is it’s this thing you do with something called a pen and paper!  But I digress back to the letter writing… if you write a letter that needs to go in an envelope chances are you need to fold the paper so it fits.  Folding it causes creases which ultimately affect the quality of your perfectly smooth paper.  The folds don’t ruin the letter but do make it slightly less than perfect.

It’s the same with mp3 and AAC formats, you’re reducing the file size so that it can squeeze into an envelope and be posted to the end user through one of the streaming services Spotify, Apple Music, Pandora are really no more than your local postman delivering your mail.

Just the same as with folding a letter carefully minimises it becoming crumpled it’s possible to minimise the risk of your music being ruined by compressing the music in the wrong format.

It’s All In The Mastering

Mastering is an art form in itself and if done incorrectly can really break your music even before you’ve bounced the file to a compressed format but ultimately mastering is about ensuring your music is ready for distribution whether that’s online for streaming or pressing for vinyl.

Things that are important in mastering are balancing the frequency response of the music and enhancing the sonic character.  Ensuring a body of work or album is consistent from song to song, although I would argue for everyone other than top tier artists albums are becoming less important.  I recently read an article in Music Week that other than the highest profiled artists albums are no longer being consumed as a complete work, individual songs are finding there way onto playlists so the linear album is less important than it used to be.

So in this post we’re going to look at the best ways for prepping your mastered files so that wherever they end up, Soundcloud, a Spotify playlist or in Apple’s music store they’ll be perfectly tailored for the streaming world of your choice.

What is Lossy?

In essence lossy encoding means that bits of your music are disregarded when being bounced, which means an mp3 is less than perfect in its quality but ensures a smaller file.  What’s crucially important is that this encoding, programmed by clever music-maths-heads, ensures the bits that go missing won’t be noticed.

If you’ve ever put a low pass filter on a track you can hear the music losses the top end the more you filter.  This in some respects is an extreme version of what lossy encoding does, it just does it very cleverly across the whole frequency spectrum and in minute detail so that it goes unnoticed.

The problem is though that encoding incorrectly or for the wrong format can cause errors even clipping; even if the file is levelled below 0dBFS it can still creep above 0 and ruin your perfectly produced music.

The Logic Pro X Mastering Solution

So how do you go about ensuring your music is encoded correctly for the internet?

Whatever style of music you write it’s important to know in advance where your music will be ending up?  Where are you going to be uploading to on the net?

If you’re uploading to streaming services these tips will help you prepare perfect lossy files for the right outlet.

Let’s begin!

SoundCloud Mastering

Currently SoundCloud converts and streams all audio at 128kbps mp3 on their site.  No matter what format you upload the files in SoundCloud will convert it and stream everything at the same rate.  If however you if decide to allow people to download your music they will download it in the original format so it’s well worth uploading high quality files.

My advice would be upload to SoundCloud uncompressed at 24bit or 16bit/44,100kHz, which means your file will be converted to mp3 just once and anyone downloading it will get a high quality file once downloaded.  This will preserve the quality of your music in the best possible way.


Mastering In Logic Tips

When mastering for Soundcloud in Logic Pro use the Limiter with True Peak Detection on.

Set the limiter to anywhere between -0.5dB to -1dB to ensure you have at least 0.5dB of headroom ensuring no clipping occurs.

Even though Soundcloud doesn’t currently have an Apple like SoundCheck system allowing you to effectively rinse the RMS of your music I wouldn’t advise that.  For one SoundCloud have already announce it’s on their radar to implement some kind of platform levelling system and two your music might end up on other streaming sites which will re-level your music so ultimately there’s little to gain.


Good practise would be to level your music at an LUFS of -16 with a maximum of -13LUFS.

One last thing to consider for SoundCloud is how wide the mix is in the top end.  File conversion going down to 128kbps is about as low as you can go before even the layman will notice the music sounds bad.

Stereo imaging in the high end is the first mp3 side effect to really suffer so if your hats and percussion are really wide in the top end you might want to think about narrowing it down a touch.  You could do this with the direction mixer of even try out Logic’s Stereo Pan to pull the sides in a touch if it needs it during the mastering stage?

YouTube Mastering

Youtube uses video codecs to convert audio files to AAC and the quality of the audio stream is selected by the end user, you know the little icon in the bottom right of the screen that let’s you choose the picture quality?  That’s the one that will alter the audio quality too.  The highest quality the audio will stream at or be converted to is 384kbps AAC even if it’s with a 4K video file.  Don’t despair though 384kbps is gonna sound pretty good.

For Youtube, like SoundCloud you want to upload the highest quality audio file, 24/44 will be a good starting point but it is well worth embedding it with a H.264 video file.  You want to embed your music and render it at H.264 the upload the video to ensure the best results.

YouTube levels files at -13LUFS so it’s worth keeping that in mind and an eye on the LUFS meter when you’re mastering your logic files destined for YouTube.


Mastering In Logic Tips

When mastering for Youtube in Logic Pro X use the Limiter with True Peak Detection on.

Set the limiter around -1dB to ensure you have good headroom with no clipping.

Once you have rendered the file you’ll need to import the music into a video editor and then render the video with whatever visuals you create ideally uncompressed in H.264.  Uploading an already rendered video file is the best way to preserve audio quality.


iTunes Mastering

iTunes likes uncompressed 24bit wav files that are then converted to 256kbps AAC ready for download.

iTunes has the very popular SoundCheck which automatically levels all music in your stream to the same audio strength so there’s definitely no point in really crushing the dynamics of your music as you’ll simply end up with a thin, weedy sounding track and if it’s floor fillers you write you don’t want that!

Master your track to an LUFS of -16 using Logic’s Loudness Meter; when you’re mastering don’t go overboard with the Limiter.

Speaking of which…

Apple suggests leaving 1dB of headroom in their Mastered For iTunes guide so setting the Limiter to -1dB is a must to ensure iTunes likes the way you’ve mastered your music and will therefore treat it respectfully.

With iTunes you really don’t need to go overboard with dynamic compression and limiting, in fact the more dynamic your music the louder and more lively it will sound.  This is because SoundCheck will re-level your music to -16LUFS so a track with limited dynamic range in iTunes now sounds worse than a track which is ultimately quieter but more dynamic.


Mastering In Logic Tips

A great tip to ensure your music will sound the best it can when in iTunes is to master in Logic and then import your files to your iTunes library.  With SoundCheck enabled play your music against other tracks in your style and see how your music compares.

If your music sounds bigger and better or simply the same as other commercial music then you know you’re doing a good job on the mastering front.  If on the other hand your music sounds smaller then it’s clearly back to the mastering drawing board, perhaps that limiter is just a touch too much or the compressor is hitting the music too hard?

Once you got it just about right render and upload the full quality uncompressed files and let Apple post your music to your fans!


Do You Want To Learn More About Mastering?

Mastering is the process of taking your final mix and making it ready for the world by adjusting the stereo, frequency and dynamic balance of your mix. You can learn how to do this and more by joining us at miL by signing up for you free miL mastering guides!

Why not sign up for you free miL guides!

Happy Mixing and Mastering!

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