Frequently Asked Questions


What File Types Do You Accept?

We prefer to work with 24-bit or 32-bit files, but we accept any combination of bit and sample rates, and virtually any file type, though WAV, AIFF, and FLAC are the most common.

Please supply your files in their native sample rate (44.1k & 48k are most common). Don’t upsample or downsample them from whatever your mixing DAW has set.

Also, Converting back up from 16 bit or MP3/AAC/OGG, if the file has been made thus, will not improve anything.

Please stay at 24bit or 32bit float throughout your mixing process.

Stem Mastering - Do's, Don’ts, & Explanations

4 Items to consider when approaching Stem work:

1. Stem Mastering, an Explanation:

Mastering with the use of subgroup / bus stems can be a great way for us to make subtle changes or correct problems in an instrument or vocal, without affecting other components of the mix. 

Essentially, we’re still just mastering it as we would a stereo file, but because with stems everything is separated into groups, we have a greater degree of control over how we make changes. One of the main obstacles we run into is that this process can be mistaken for handling some or all aspects of mixing the song.

Mixing (which is a completely different process than mastering) can take a good deal of time, & requires different treatment than stem mastering process can provide.

Please also note that stem mastering is billed at a different rate than stereo mastering.

Lets clear any confusion around the differences between


2. The Differences of Mixing & Mastering from stems

While both can be done with the use of consolidated stems;

Mastering from stems is the process of finalizing an artist’s approved final mix, slated for release.  …And in the case of mastering this mix from stems: we require Bus/Subgroup/Grouped element stems that have many elements that play together – grouped for output – in the mix stage. See the list in “Submitting Stems” below for clarification.

Mixing from stems, however, is the balancing of all of the raw elements of a song in order to create a final mix, BEFORE the mastering stage. In this case, the stems provided are called raw tracks or raw stems, and are unique mics / sounds in their separate channel lanes to be blended together in a mix session. Like Kick, Snare, Hat…. Guitar 1, Guitar 2, Synth 1… Lead V, Backup V,  etc…

There will be many more raw files for a mixing session than in the case of stem mastering. For most situations, if there are more than 12-16 Stem Files, that probably goes more into mixing. See “submitting stems” below to make this clearer.

If for some reason we end up delving into mixing aspects, we would need to talk about our mixing rates if this is helpful for your project. So, unless you want us to do the mixing, you will want to get everything exactly as you think it should sound using Bus Groups, before you print stems to be mastered.

If you need help with this, Thaddeus does screenshare consults almost every week these days helping people prepeare their sessions for the best outcome. Just drop a request in the contact form!


3.Submitting Stems for Mastering:

When supplying stem files, make sure they are all synchronized (beginning at the same timestamp), and be sure to also include a Final Mix file stem, that sounds identical to the provided group stems when summed together.

There are no specific rules as to the numbers of stems you can supply but each stem should represent a submix of similar song components, and not raw takefiles of individual tracks.*

If you end up with stems of raw (upstream of group output) tracks, (See above! “Creating more than 12 stems in total..”) this will not get you what you want from the mastering process. Also, it is usually best to set up Vocal or lead element FX in their own Stem, using auxiliary sends – with the FX return tracks grouped to their own “FX bus”.

*Bonus points if you can combine mix busses in your session to less than 10 stem tracks!


Typical Stem Mastering Setup example:

Stem 1: Percussive elements/Drums
Stem 2: Bass instruments
Stem 3: Guitars, lead synths, etc.
Stem 4: DRY Lead & Chorus vocals – Please print vocal FX on their own stem or with all FX (stem 7)
Stem 5: Background vocals or secondary synths
Stem 6: Background layers, incidentals, random 1-off sectional changes, etc
Stem 7: Reverb & Delays, other FX (If there are vocal-specific FX, it is best to print them on their own FX stem)
Stem 8: Full Stereo Mix of all combined stems. This should be your final – artist approved – mixdown.


4. Preventing Issues In Stem Mastering:

In order to assure the stems are exactly the same as the stereo mix, we recommend;
1. After creating all the group stems, create a new empty project in your DAW.
2. Drag all these stem files in on new tracks, and the Stereo Mix as well.
3. Mute just the Stereo Mix stem.
4. Play the song.
5. While playing, toggle SOLO on just the Stereo Mix stem, and if you hear NO CHANGE WHATSOEVER from the combination of the group stems to the Stereo Mix, they are ready for mastering.
6. If you hear differences however, we will not be able to achieve exactly your stereo mix to start with, which isn’t optimal. If the change you hear isn’t a problem, and you are aware that we will be working from that stem combination, rather than the stereo mix, we can get started.
Files we will provide once you approve the masters:
24 bit WAV at your native sample rate
16 Bit WAV at 44.1khz for CD

HQ 320 Kbps AAC for fast sharing with friends or collaborators (please only use the WAV files for submitting for distribution online, or for use in videos)


• Files optimized for vinyl
• Files optimized for cassette
• Master Reference CD’s – we charge $10 per CD-R
• If you have need of a DDP file for CD printing houses that require them, we charge an extra $80 to build that. This can also be done at any time in the future, as we keep your session files forever. Most CD duplication houses just want WAV files uploaded directly through their site nowadays
Apple Digital Masters (formerly “Mastered for iTunes”) files. we just charge an extra $80 to build those for album releases
ISRC if you need them generated
How Much Headroom?
There is no absolute requirement as to how much headroom there should be in your files. With 24-bit files, it could be -12dBFS or it could be hitting 0dBFS, but max peaks hitting -8 to -3 on the main output meter of your system are great.
What is required, is that your songs waveforms haven’t exceeded 0dBFS in your DAW and thus been clipped off! When in doubt, give yourself at least a few dB above the highest peak in the song. Alternatively, you can avoid clipping altogether by printing your mixes at 32-bit with no dither. We still recommend adhering to ‘normal’ gain staging theories and to avoid 32-bit mixes with peaks above 0dBFS, but this format does provide protection against errant peaks.

Avoid sending songs that have been squashed using limiter plug-ins. In mastering, we can get it just as loud, and usually much louder while retaining more punch and transient clarity, should this be your goal. Bypass any plug-ins that exist on the main output channel that you are using solely for loudness.

That’s not to say you should remove everything on the master channel, just the final limiter. If there are plug-ins on the master channel you love, such as compressors or EQ’s that you feel contribute to the songs character and feel, by all means leave those there! But it’s important that you don’t clip the master channel, not only to allow us room to work, but also to allow for as much clarity as possible in the finished product. 
See this chart for info: Dynamic Range Tips
Dynamic Range?

This is often confused with headroom, but DR is about the somewhat short term average loudness as compared to the absolute peaks of the material. This can be measured in the short term by RMS meters, but most use LUFS meters for this purpose now. A great dynamic range is usually at or greater than -12dBFS (LUFS). See this chart for info: Dynamic Range Tips

Track Notes or Requests:

It’s helpful if you can point out anything specific about the songs you’d like addressed that you couldn’t accomplish in the mixing stage. Include these in the track-notes section of the pre-mastering checklist we will email you. If there are drastic problems you can’t get around in your mix, let’s talk about mixing or doing mastering from group stems.

Track Spacing:
Please get us a list of spacing between tracks, if you have a preference. Usually listed as (.25 sec, 2 sec, etc) before or after the name of the song in your list is easiest. We set track spacing entirely by feel for the rhythm if you don’t include this info. If your project includes cross-fading between songs, send songs that have already been cross-faded and then cut into separate tracks.  We can maintain their seamless transitions during mastering. Or, if that hasn’t happened yet, just send the tracks the way you have them and give us info on how you would like them to land.


Out of all the relationships you will build in your musical journey, none can bear more fruit than working with someone who cares just as much about your project as you do. If you feel like you can’t find anyone to match your tenacity, you need to meet Thaddeus at Liquid Mastering. We are so thankful to have connected with him early in our career; we cannot recommend him enough!

Milan Patel - HELLO DILLY


Digital Distribution & Streaming - What File Types will I need to upload to my distributor?
This covers distribution/aggregation services like; TuneCore, DistroKid, CD Baby, Indigoboom, Record Union, etc., and streaming platforms such as Spotify, iTunes, Apple Music, and TIDAL.

Each aggregator listed above have slightly different requirements for submitting files, we recommend you walk through your chosen system to learn what you will need to submit. They are all trying their best to make it easy for you.
As far as audio quality, currently, the safest format to use for digital distribution, aggregators, and streaming is a 16-bit 44.1kHz WAV file. While some say they accept any number of sample and bit rate combinations, what is not clear is how they are converting higher sample rates down to the streaming standard of 44.1kHz.

At LIQUID MASTERING, we use the best possible sample rate conversion currently available, and this will ensure your streaming masters sound their absolute best. Please use the supplied 16-bit 44.1kHz master/s for these services.
If you’ve supplied your mixes at higher resolutions we’ll also provide a set of masters at their original bit-depth and sample-rate for archival, and for anywhere that supports high-res audio such as Amazon HD, Apple Digital Masters™, and Bandcamp.


Apple Digital Masters (Formerly Mastered For iTunes)

Liquid Mastering is an Apple approved supplier of “Apple Digital Masters”. If you’re selling and streaming your music on iTunes and Apple Music and would like to take advantage of Apple’s optimized Apple Digital Master format, you’ll need to supply us with 24-bit mixes. Ideally, the sample rates should also be higher than the standard 44.1kHz with 96kHz being preferred, but currently, only the 24-bit specification is mandatory. We’ll retain this high resolution through the entire mastering path, and carefully prepare the masters according to the Apple Digital Masters specification. Masters created for this format can be up to 1-2dB lower in volume to account for inter-sample-peaks (ISP’s) and clipping which can become distortion during playback of the AAC format. Put simply, files prepared in the Apple Digital Masters format will play distortion-free, providing the end-listener the highest fidelity in a lossy format.


YouTube currently streams everything at 44.1kHz, so if you’re uploading just audio, it’s best to upload a 24-bit 44.1kHz file to avoid further sample-rate conversion. However, if you’re uploading a music video, which are commonly created at 48kHz, we’ll supply a 24-bit 48kHz master for the video editor.

For Bandcamp, use our supplied 24-bit Waves, in their native sample rate. This is an opportunity to use higher sample-rates if you worked at a rate higher than 44.1kHz to make your music.

Like all streaming services, SoundCloud uses a lossy compression algorithm for its streaming audio that has the potential to create audible distortion and crackling during playback. If you plan on uploading your masters to SoundCloud, we can prepare a special set of files to ensure you’re getting the highest-fidelity that is distortion free. Like Apple Digital Masters (MFiT), these masters may be slightly lower in overall level.

Thaddeus has been great to work with. Being on different continents communication is crucial and he’s been brilliant every step of the way. Awesome final mastered product as well! Highly recommended

Neil Walker - WARD UK


As vinyl has particular physical limitations as compared to digital files, we recommend not using the digital masters for vinyl production. We like to have a separate session to provide files that will be perfect for the vinyl press. Our vinyl optimized masters have all the dynamics, color, and equalization processing of the digital & streaming formats, but we back off on the final limiting to allow more transient clarity and punch. This gives your record more life and dimensionality in the needle groove. It’s also possible we’ll get more aggressive on sibilance and excessive high-end as these can end up as distortion on the record. We adjust excessively wide low-frequencies (also known as phase issues in the stereo field below about 120hz), as these will often cause cutting issues. We’ll analyze and check your mixes for that during the mastering process, and if we find it to be problematic, we may ask you to revisit the mix and make corrections there.

It’s standard practice to always get a test-pressing so you can hear exactly how the record will sound before you’ve had a full order pressed. This can be an opportunity to revisit the mastering or lacquer cutting to correct issues that may not be apparent until we near the end of the process.

Our vinyl masters are supplied as a 24-bit single Wave file for each side of the record. With Vinyl, you want no more than 24 min per side, or it will lose low end definition on the last few songs. Sometimes, it’s best to arrange the tracks differently than the digital version, to have the ones you want for most impact first on each side of the LP.
Cassette masters are supplied as 24-bit files, one for each side of the cassette. If your duplicator/replicator requires 16-bit files, let us know and we’ll provide them.


CD Pressing Houses Requiring DDP
Our CD masters are supplied in standalone WAV files, unless you require the DDP format.
As these take more time to assemble, there is an extra fee. If you require DDP, please let us know as soon as possible. This will be a folder of files delivered as a single compressed Zip file. Before sending to your replicator, you’ll use the included DDP player (PC & Mac) to see and hear the CD exactly as it’s going to be once manufactured. You can even use the player to burn reference discs (Note, these discs should not be sent in for replication) as well as export individual 16-bit Wave files. Check all the song titles, album title, artist name, ISRC’s, and UPC for accuracy. If everything is perfect, you can send the original zipped DDP folder to any CD manufacturer of your choice and they’ll be able to replicate perfectly from it.


After hearing some of Liquid Mastering’s other work, I knew where I wanted my project to be mastered. With a careful ear and a commitment to excellence, Thaddeus made sure my project got what it needed to sound it’s best. He loves music and it is important to him that things sound great. Plus he’s a hell of an individual too. I highly recommend him for your mastering needs.

Scott Austin


ISRC (International Standard Recording Code) is the international identification system for sound recordings and music video recordings. Each ISRC is a unique and permanent identifier for a specific recording, independent of the format on which it appears (CD, audio file, etc.) or the rights holders involved. ISRC’s are widely used in digital commerce by download sites and collecting societies and they provide the means to identify recordings for royalty payments. In mastering, we can embed your ISRC’s into the DDP master, if you elect to use that option, please provide the code sheet given to you by the aggregator you purchased them from. Also, if your distribution service won’t provide them, we can generate them for you, see the pricing page for details. 
CD Text & Metadata
CD Text is different than what you see when you load a CD into iTunes and the information automagically loads. CD Text is stored on the physical CD for the purpose of displaying album information in compatible CD players. Your CD duplication/replication company can embed the CD text however you like, usually upon the uploader page of their system. It can also be read from the DDP we will provide, should you elect to use that option.  But the information that shows up in iTunes is pulled from online databases, like CDDB or Gracenote. We handle CD Text here in mastering but this online information can be submitted by anyone using iTunes or any equivalent program supporting submissions to online databases. We recommend you take a CD that you get back from replication, insert it into the CD drive in your computer, and then with iTunes, tag the album exactly the way you want it to appear for others. Choose “Submit CD Track Names” from the advanced menu and this ensures you are the first to submit the info to the online database so the information will appear for everyone just the way you intended it. There is, unfortunately no way to do this before the CD’s are printed.