About Check Your Master

Check Your Master is a web-based audio comparison and analysis tool that we originally built for our mastering clients and later expanded for our own use.

Why we built it

We built the original Check Your Master web app in 2023 to give our clients a simple way to compare the master with their original mix, without needing to use a DAW or any complicated tools. This removes some of the uncertainty from the process, especially for clients who don’t use a DAW on a regular basis.

One problem when comparing a master with the original mix is that the master is usually louder. Even relatively small differences in level can make a fair comparison difficult, as the louder version will often be perceived as fuller, clearer or simply better.

Check Your Master addresses this by loudness-matching the files automatically. This makes it possible to switch directly between the mix and master at the same perceived level, making the comparison more meaningful.

Since we started using this tool with clients, we’ve found that the feedback we receive tends to be more precise. Discussing possible revisions is easier when everyone can make the comparison under the same conditions.

The Advanced version

After using the original version for a while, we started building a more detailed version for ourselves.

During mastering and QC, we always compare the finished master with the original mix in several different ways. Apart from listening at matched levels, we look at changes in spectrum, stereo width and loudness over the course of the track.

We also want to clearly hear and see what happens to a master after loudness normalization, as this is commonly used by streaming platforms and other playback services.

Rather than moving between several tools, we wanted to have these comparisons available in the same place. That became Check Your Master – Advanced.

How we use the advanced version

We mainly use the advanced version of Check Your Master for comparison, analysis and quality control. Quality control has always been an important part of our mastering process. A finished master will be heard through many different playback systems out in the world. It will also be heard at normalized playback levels nowadays. We want to have full control over how the master behaves under those conditions, as well as how it differs from the original mix.

The advanced version can be used to:

• Load one or two audio files and measure their loudness
• Switch between files with automatic loudness matching
• Set a target loudness for the comparison
• View the spectrum in real time or as an average across the whole track
• View stereo width in real time or as an average across the whole track
• Follow momentary and short-term loudness over time
• View the integrated loudness gating level and the sections excluded by the gate
• See the difference in spectrum, stereo width and short-term loudness between two files
• Monitor the audio in stereo, mono/difference, or as separate left and right channels
• Flip left and right in the monitoring to quickly check the stereo balance
• Apply high-pass and low-pass filters while listening to emulate small speakers
• Isolate and monitor selected frequency ranges directly from the spectrum view

We’ve also used the app in some of our YouTube videos when analyzing masters and discussing different aspects of mastering.

Current status

Check Your Master – Advanced is still in development. We built it primarily as an internal tool, and there is currently no public version.

We also think it could be useful to others who work with recorded music and want a straightforward way to compare and examine finished masters. We can imagine it could be helpful to other mastering engineers, mixing engineers, producers, musicians and record labels.

For now, we’re inviting a small group of people to try the advanced version while we continue to develop it. The app is free to use for a period of time after receiving an invite. After that, we are planning to make it possible to continue using the advanced version and support its development for a small monthly fee.

If you would like to try it, you can send us an email.

The original version of Check Your Master started out here on this site, as a tool for our clients. Since then we have made a separate website for the app, which is where the advanced version will be available as well. (The original version here on this site will be retired soon, and any future updates will happen on the main site.)

Screenshots