File formats and how to deal with them

(© Jeffrey de Gans v2.6, 10 September 2021)

There is a lot of misinformation and misunderstandings about various audio formats and streaming services in particular. In this article I will explain how things work and how to deal with the different master formats you will get from me.

Listening and quality check

Please listen to the delivered masters on various playback systems. Listen to them in your studio, car, living-room, various headphones and any other medium you’d like to listen to. Make sure that you don’t use any EQ or other ‘sound enhancement’ systems during playback. Compare to other music in the same genre. Does the music touch you, move you? If not, please let me know with feedback on what you are missing and I will make a revision based on that. 

Albums/EP’s should be judged as a whole, rather than individual tracks.

The delivered masters and filenames

Depending on the types of masters you asked for and in what format you delivered the mixes in, this is what your masters will look like. Let’s presume the delivered mix was in 24bit 96khz and was named 01 Songtitle.wav, the masters will be named like this.

(mastered 17-4) means that the mastering was done on the 17th of April. If I do a revision which is delivered the day after, the file-name will be 01 Songtitle (mastered 18-4).wav. When I send you a second version the same day, it would be 01 Songtitle (mastered 18-4 v2).wav. This way you can always see which is the latest version and when the mastering took place.

What masters should go where?

Depending on the types of masters you asked for and what format you delivered the mixes in, this is what your masters will be named to. Let’s presume the delivered mix was in 24bit 96khz and was named 01 Songtitle.wav, the mastered files will be named like this.

  01 songtitle (mastered 17-4) STREAM 2496.wav
Hi-Res Streaming masters in 24bit 96khz
for use with distributors that support 24bit files with high sample-rates. Most distributors support higher sample-rates nowadays since a lot of the streaming services started offering hi-res/lossless streaming.

  01 songtitle (mastered 17-4) STREAM 2444.wav
Streaming masters in 24bit 44.1khz
are dedicated masters for streaming services in 24bit 44.1khz WAV format. Pretty much all distributors support 24bit nowadays. This master should also be used for soundcloud, YouTube, bandcamp etc.

  01 songtitle (mastered 17-4) STREAM 1644.wav 
Streaming masters in 16bit 44.1khz
are dedicated masters for streaming services in 16bit 44.1khz. Just use this 16bit streaming master when the distributor doesn’t support 24bit files. To my knowledge, just CD baby supports 1644 files only.

  01 songtitle (mastered 17-4) ADM.wav
Apple Digital Masters (ADM)
are 24bit masters dedicated for the Apple Digital Masters (Mastered For iTunes) program. Only certified mastering-engineers can deliver ‘ADM’ Masters. Please mention that I was the engineer or they might be rejected.

  01 songtitle (mastered 17-4) 2496.wav
Regular 24bit 96khz masters
are hi-res masters for DJ download portals etc. 24bit is always the best option so where possible, use this 24bit master, or even better, the streaming masters. Also keep these masters in your archive.

  01 songtitle (mastered 17-4) 1644.wav
Regular 16bit 44.1khz masters
used to be the most commonly used masters for DJ download portals etc. Nowadays 24bit is always the best option so where possible, use the 24bit master or even better, the streaming masters.

  01 songtitle (mastered 17-4) VINYL.wav
vinyl master in 24bit 96khz Dedicated masters for vinyl in high resolution WAV format. Most cutting-engineers prefer one long file per side with all transitions and information. I can/will also make that file for you if the right track order is supplied.

  01 songtitle (mastered 17-4) MP3 320kbps.wav
320kbps mp3
Never use MP3 files for uploading to an online distributor or another service like SoundCloud, this will result in distorted and low-quality audio. Always use WAV files in preferably 24bit.


Uploading to digital distributors/services do’s and don’ts

Distributors like Distrokid, Tunecore and CD Baby will get your music online. Think of it as distributors of CD’s/vinyl records back in the days. They took care of the delivery to all record-stores, even the ones you didn’t even knew existed.

Nowadays the majority of distributors (except for CD baby frown) supports 24bit with 44.1khz (or higher) WAV files. 24 bit will always sound better when converted to a lossy format. Also Apple Music recently came with the news that they will be offering Hi-Res/lossless streaming in 24bit and soon, Spotify and other will follow. So I suggest to always upload the 24bit STREAM masters that I deliver. Be careful, some aggregators seem to support the upload of MP3 files instead of WAV files, which is a BIG No-No! When you do that you will get ‘transcoding’, which is basically 2 layers of lossy encoding on top of each other and that will totally mess up the sound. This is also a big mistake that people seem to make when they upload their music to SoundCloud. They upload an mp3 and wonder why it sounds so bad. Always upload 24bit WAV files to SoundCloud and and use the streaming/STREAM master that I deliver.



Streaming services and loudness normalization

By now you might know that all streaming services use loudness normalization. This means that no matter how loud it is, it will always play back at the same perceived loudness. But is it..?

The biggest misconception is that masters for streaming services should be -14LUFS. This is not true! As a matter of fact, I don’t think it’s a good idea to master to -14LUFS at all! Pop, Dance, Rock, EDM will most likely miss ‘power’ when mastered to -14LUFS because the limiting and compression are ‘part of the sound’ and you don't always get that sound when you master to -14LUFS. But also, what about Apple music, they are at -16LUFS? So you need multiple masters for all of the streaming services? That is not what you want! You just want one master that will work everywhere. As a mastering-engineer, I will make it sound great and I don’t focus on the numbers. If a master sounds great at -13LUFS, fine. If a masters sounds brilliant at -6LUFS, awesome! It’s not about numbers, it’s about music. Sure those louder masters might be turned down more to get to the right level, but then it still sounds great.

Besides 'regular' masters, I deliver optimized masters with streaming services in mind. The main focus always is the sound, not numbers.

More information about the loudness war and how loudness normalization works can be found here.

WARNING! Distrokid offers an option (see screenshot below) where they will adjust the level of your mastered song(s) to match Spotify’s target playback level and then send that to ALL the streaming services. Please, never use this option, you will waste money and your precious masters but it will most likely make your music to appear less loud on certain streaming services.

Physical Mediums and file formats

In 2021 streaming is the default medium, but the physical product market is still alive and kicking. It actually got bigger in recent years. People still like to have something physical like a vinyl record, CD or even an old-school cassette.

Those physical products need a different approach then a digital release. You need dedicated masters for Vinyl and a DDP image for CD. Read more about this below.



Vinyl is a delicate medium and not all masters are suitable for cutting/pressing to vinyl. Digital masters with limiting and/or clipping will not work great for vinyl. Also masters with a lot of sibbilance or out of phase low frequencies will be problematic or even impossible to cut. I can make dedicated masters that will work great for vinyl cutting, but I need to know in advance that you will also release on vinyl so that I can make those ‘vinyl ready’ masters.

Vinyl is a delicate and 'living' medium and you can never 100% predict how it will translate to vinyl. It's a combination of the masters, who is the cutting-engineer, what lathe does he/she use, how was the plating done, how is the pressing, quality of the vinyl, a lot of factors count. That's why I always advice on having a test-pressing to avoid unpleasent surprises. Besides that, it's always fun to have a test-pressing and have that first magical moment on hearing your music played back from vinyl. 

Not sure if your turntable setup is correct for judging a test-pressing? Send me a copy and I will take the time to do that for you on a calibrated turntable with various industry standard cartridges.

Maximum running-time
There is a maximum of audio which can be cut to vinyl and even though they are just rough numbers, they will give you some guidelines to keep in mind.

12 inch @ 33RPM: Optimal 16 to 20 minutes, max 25 minutes
12 inch @ 45RPM: Optimal 6 to 12 minutes, max 15 minutes

I will also make one long hi-res WAV file per side so that all transistions will be exactly like you want them to be once pressed to vinyl.


Compact Disc and DDP images

For a physical CD release you need a DDP image, a 100% error free image of the CD that will be send directly to the CD factory. This DDP image contains not just the audio, but also all information like CD text, ISRC codes and UPC/EAN codes. This means you need to prepare that in advance. I have made and excell sheet where you can fill out all this information, which you can download here.

sidenote: when a CD factory doesn’t support DDP images, go somewhere else. There is NO excuse for not supporting DDP images.

Sequencing and transitions

Something which is really important for an album release is obviously the track-order, but just as important, or maybe even more important, is the sequencing of the album, the transitions between all tracks. By using the right transitions (pauses, fades), you will turn an album into a real album instead of a collection of tracks. I can do the transitions for you by using my gut feeling, but if you have a vision on that yourself it would be great to know that. 🙂

Useually for CD and Vinyl I can do the same transitions.


Please use one of the following credits when mentioning me as the mastering-engineer.

  • Mastering/Mastered by Jeffrey de Gans at Da Goose Mastering
  • Mastering/Mastered by Jeffrey de Gans
  • Mastering/Mastered at Da Goose Mastering

I hope this information helped you understand how things work. If you still have questions, feel free to ask.

With kind regards,

“Mastering is the final step before your music is released to the world. I take that very seriously.”

Da Goose Mastering is an approved ADM studio

Approved Apple Digital Masters provider

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