Your mastering questions and our answers to them

Audio Mastering is an involved process that can take a bit of time. Generally mastering a track should not take too long, but sometimes we like to come back to a track to see how we feel about it.

In other words, we can rush the jobs, but we like to spend a little more time to check that all is well and that we're happy.

Equally we would love your involvement. Feel free to feedabck and ask about any changes you feel are necessary. This is important to us.

Loudness then & Loudness Now

What is Loudness Normalization in the late 2020s?

Dynamic range is an important part of music, and compositions come with their loud bits and also their quiet bits. We like the power of a dynamic rock anthem, or something that drives you to dance! Surely we should aim to keep that alive?

Some loudness history
As the decades went on, this dynamic range became more and more squashed sadly. This was not necessarily for any technical deficiency, but because sonic tastes required it and something called the Loudness War became something entrenched in audio and music society. The origins of the loudness war can be traced as far back as jukeboxes and 45rpm 7"singles. Engineers such as Joe Meek, then working for IBC in London would engage equipment he'd built and techniques he'd invented to ensure that his records were louder than his contemporaries. It worked. More clients came asking for him to make their records.

In the analogue world this worked, as far as the reproduction system (amp, speakers etc.) could handle it. Even a touch of analogue distortion is argued to be a wonderful thing. Harmonic distortion can give crunch, bite and a lovely feel. Think about how many plugins there are on sale offering tape saturation for example (an expected necessity to record levels at high signal to noise ratios to rid ourselves of the noise floor inherent on an analogue tape based recorder for example).

However it all changed when digital became the norm. No longer was 0dBu the guide level we sort of worked to and the analogue system could be pushed and pushed until something (the tape, or player, amp, or speakers) broke rank and produced unpleasant distortion. No, in the digital world, 0dB became a bulls eye - a target!

Each record that was put out was expected to be louder and louder. In essence, compression and limiting techniques were employed over several decades to reduce the difference in level between the loud and the soft moments, so what we'd call the average loudness (VU) would be raised eventually to be as close to the peak (loudest) level as possible.

The Loudness War pinnacle sort of happened with Death Magnetic from Metallica. The associated game's audio was not subject to the mastering compression sought by the band. So much so that fans asked for the game version of the audio to be released.

However it is not as simple as making things ‘one louder’ (Nigel Tuffnell in Spinal Tap, 1980) anymore! The digital world has changed away from a CD based diet to a streaming one. And at the same time, work by industry (especially broadcast) has started to pick up long-lasting conversations about loudness and have moved standards to what we call equal loudness. Essentially it now means we measure the loudness of a track over its duration and give it a number.

Streaming sites like to dictate what they optimally work at, whether that's -16dB LUFS or -14dB LUFS. We can prepare your masters to exactly meet this requirement, but clients, these days, feel that this is too quiet when uploaded to streaming, so we tend to push to a louder point where the music works. This is not the loudness war per se, but something where the dynamics are retained and the music has some additional life.

Please contact us with your requirements and should you wish to discuss this further.

ISRC stands for International Standard Recording Code and is a way by which each released song is given a unique identifier.

This unique identifier is a string of numbers embedded into your Broadcast WAV or CD.

The idea is that as songs are played on the radio etc. the ISRC codes can be logged and any royalties can be collected for that song automatically. At the mastering stage of the production process, we encode these ISRC’s into Broadcast WAV files and CD masters alongside the UPC/EAN Barcode (for CDs).


An ISRC contains a country code (UK these days) and then a registrant code which can be you, or your label. Next is the year of release, then a five digit code for the designation that your particular track is assigned to.

Getting ISRC codes (UK)
This is not a service we can provide as this is managed internationally and operated nationally by appointed operators. For the UK this is PPL. To obtain your ISRC codes, please go to PPL’s ISRC website – https://www.ppluk.com/membership/more-information/isrc. They will ask you to provide them with certain bits of information… Once you have the producer code part of the ISRC please pass that to us.

Obtaining your codes does not usually take a great deal of time to obtain and are free to the user. It would be best to be prepared and consider these at the beginning of the mastering so they can be ready when we complete you streaming files (Broadcast wavs) or your CD image for you. PPL will make you aware of your obligations as the owner of these recordings and ISRC codes

Whilst we’d like to obtain barcodes for our CD producitng clients, it's not advisable. Ideally you may wish to factor time for this in. The barcode associations would prefer we did not do this on your behalf.

To get your own Barcode, please visit https://www.gs1uk.org/get-a-barcode/for-music who are one of the main authorities in the UK, although other options are available with a quick internet search. Be sure you're asking for a barcode for your music, and not a range of pasta selections you're hoping to make. The latter barcode band might cost considerably more.

Obtaining barcodes can take a little time, so we would suggest that you get in touch with GS1UK as soon as possible at the start of the mastering project so that the code is ready for when create your CD image. For more details, do not hesitate to contact us.

Preparing your files is really important if you wish to get the most out of the mastering process.

We advise that you send your files at the same sample frequency and bit depth you've been working at as you record/product (likely to be 48kHz and 24bit).

If you have been mixing into or have used a compressor or limiter on your master buss (or afterwards), please could you send us an additonal version with this disengaged/bypassed. This will provide us with more room to work the dynamics the way they're needed for mastering.

Before sending your audio over, be sure to speak to one of us so we have understood your project and have all the details we need.

Please either use WeTransfer.com or contact us if you'd like to use a DropBox space

If you have more questions, please do not hesitate to contact us on +44 (0) 7941 512 215 or via info @ mottosound.co.uk