Streaming Takes Over — Are Your Mixes Ready?

By in Music Creation, Pro Mixing

With double digit sales growth for recorded music in the US for the first time in almost 20 years, things are looking up. Streaming led the charge with sales now accounting for more than downloads, CD’s and vinyl combined. Are your mixes and masters optimised for this revolution in music consumption?

 

No-one is listening to your mixdown

Streams mean codecs. People are not listening to your wav or aiff they are listening to AAC and Ogg Vorbis files. These files don’t behave as nicely as the audio in your DAW.

Codecs can’t handle hot audio, in fact some of them have a lot of trouble, leading to distortion in the stream not present in the original master. To see how a codec is going to perform, you really need to be able to monitor from within your Pro Tools session. The only other alternative is to export, encode and analyse the resulting file.

Thankfully help is on the way. NUGEN Audio MasterCheck Pro puts you back in control. You can now monitor several codecs simultaneously from within your session, allowing you to make informed choices about how to handle your peak levels for optimal playback.

Avoiding Codec distortion – the secret formula

The space between the samples is where all the trouble lies. Digital audio reduces the analogue waveform to a series of discrete measurements (samples). In-between these samples, the analogue waveform continues smoothly, so in some cases the reconstructed waveform can be higher than the sample measurements either side.

Codecs can’t handle inter-sample peaks, they result in distortion as the waveform is incorrectly reconstructed. The secret to avoiding codec distortion lies with inter-sample peak measurement and limiting.

MasterCheck Pro measures the true-peak output after the codec conversion process, as the listener will hear it through their favourite streaming service. You can monitor and listen to this stream in real-time, making sure your work is best preserved all the way to the listener and avoiding any nasty surprises later on.

If you are using a limiter, make sure you have a true-peak limiter at the end of your chain, such as NUGEN Audio’s ISL 2. The harder you push a sample peak limiter, the more-likely you are to introduce inter-sample peaks.

Remember, you won’t necessarily hear the problem in your Pro Tools session (unless you are monitoring an encoding process through MasterCheck Pro of course!). Pro Tools will be happily running at a high bit depth, using floating point calculations giving a headroom way in excess of any sensible requirement – the problems only appear as you export your mix and encode for streaming.

 

Streaming plays it all out at the same loudness

Because streaming playlists often have many songs from different artists, periods in time, genres etc. the services match the loudness of each song from one to the next, to avoid the listener having to constantly reach for the volume control. This is achieved by a process called loudness normalisation.

Loudness normalisation works by analysing the entire song for its average loudness, and then turning it up or down to a set level for the system, so everything comes out, on average, at more-or-less the same loudness.

Does this matter?

In one sense, no. The loudness matching is simply a dB offset applied to the entire song, turning it up or down, there is no dynamics processing, it will sound exactly the same, just as if the playlist has an automatic volume control that only changes once, in-between tracks.

In another sense, however, there is a lot to consider. If your music (previously peaking the codec at 0dBTP) is turned down, it will now peak at a lower level. If you are used to heavily compressing and limiting your audio, it could be turned down 6dB’s or more! That results in 6dB of unused headroom you could have used for more transient detail and punch – or not, the choice is yours. The most important element here is to be informed so you make the creative decision and don’t lose out because you don’t understand the processes or fruitlessly try to be louder than the playback loudness target.

MasterCheck Pro makes it easy to audition the level of different streaming services. Just pick a preset and the meter will show you the loudness target for you to compare your work with. Hit ‘Offset to match’ and you will then see how it will come out and you can make creative decisions according to taste.

Extra Tips and Tricks

MasterCheck Pro also has a number of additional features including

  • Automatic reference track loudness matching
  • Equal loudness effect chain auditioning
  • Codec delta mode to hear difference between the codec and the original audio
  • Mid-side mode
  • Highly configurable

 

To find out more head over to the NUGEN Audio MasterCheck Pro product page.

MasterCheck Pro is also available now in the Avid Marketplace.

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Jon Schorah is a founder and Director of NUGEN Audio, developer of pro-audio plug-ins for Post Production and high end audio applications.