Almost every day, mixing and mastering engineers have to make decisions about how loud a track should be. Over the last fifteen years this decision has become much more precarious as a result of the “loudness war.” In case you weren’t aware of it, the loudness war developed once the audio world realized a louder track (when played directly before or after a quieter one) sounded better to a listener. As a result, record executives started demanding louder masters to “compete.” Consequently, engineers were placed in a catch 22, as making tracks louder required more compression, which made tracks less dynamic. Yet, clients and executives demanded louder mixes and masters, to point of either complying with the requests or finding yourself unemployed.

Enter NUGEN Audio Master Check to emancipate over-compressed audio and wrongfully pressured engineers! No other tool on the market so simply and thoroughly removes the guess work, or makes the point clearer, than Master Check. Simply put, Master Check can and should finally end the loudness controversy. Master Check achieves this by providing instantaneous comparisons to the engineer and listener. In real time, you can audition a track to see what a signal chain and over compression is doing while removing “loudness” from the equation. Moreover, Master Check also allows for real-time auditioning of different digital delivery mediums like Youtube, iTunes Radio, Spotify, and Windows 8 to hear what your master will sound like once those platforms apply a horrible dose of compression or volume limiting.

NUGEN Audio has created an indispensable tool here, and it goes beyond simply helping engineers and artists to make good sonic choices. Master Check can help turn the tide of the loudness war and put dynamic audio back in the driver’s seat for consumers and an entire generation of listeners. Make no mistake—this plug-in can and will have far reaching implications for the audio industry. NUGEN Audio should be applauded for not only creating a brilliantly simple yet practical tool, but also for creating something so special it can influence the entire audio industry and consumer market worldwide.


Let’s take a walk on the tech side: Master Check is a metering tool that serves Mixing and Mastering engineers. Specifically, Master Check helps create higher quality audio by focusing on loudness normalization. This goal is achieved by providing tools that monitor loudness, dynamics, and ITU (International Telecommunications Union) compliant inter-sample metering. Although there are many such products on the market, NUGEN Audio Master Check has some brilliant features that set it apart.

Some of these features are standard/familiar, but the combination of workflow design, innovative presets and simplicity make Master Check a very valuable tool:

Preset Browser: Self-explanatory, a quick trip not only shows the functionality of this plug-in but also provides fast solutions.

Short-term PLR: Peak-to-Loudness Ratio meter that gives real time analysis.

Program Loudness: Follows the ITU-R B.S. 1770 shows the integrated loudness of audio since the last reset. Used primarily as a working target for loudness normalization. The target value can be defined in the settings or from a reference track.

Short-term Loudness meter: Shows loudness levels over a three-second period and is also calibrated to ITU-R B.S. 1770. Provides real-time loudness value for audio.

Program loudness indicator: Graphic representation of loudness.

Anchor: Useful feature that anchors the Short term PLR, and is helpful if one’s goal is to view a reading against the scale.

M|S: This feature is to view metering in a mid to side configuration. Therefore, the metering is split showing mid and side instead of left and right. Overall program loudness and PLR still reflect the stereo mix, but the bar metering is mid and side in this mode.

True Peak Meter: This measures the dBTP in line with ITU-R.B.S 1770 as well as Apple’s afclip algorithm. Desired algorithms are selected from the settings panel, the meter’s top value in the maximum true peak level.

Reset: Resets all meter readings

Offset to Match: Controls loudness offset used to reach the desired program loudness target. The target can be one of the many presets such as streaming mobile or TV USA as well as an external reference. When “offset to match” is instantiated the signal will either be boosted or attenuated to reach the target loudness. This tool is primarily used to audition and/or orient the engineer and client to levels, however, if there is a large disparity between the source and target large corrections can cause output overloads. In this case, it is suggested to use an inter-sample limiter such as the NUGEN Audio ISL.

External Reference: Used to access to external audio referenced with the NUGEN Audio Send plug-in. When in this mode, the reference audio is accessed via the NUGEN Audio plug-in “Send.” This works as a side-chain insert and allows the user to see the difference between the session audio and the reference audio. This can be very useful for gain staging.

Master Check also boasts a robust arsenal of settings adjustments that are easily accessible from the front panel settings button.

Parameters include:

Color Splits: Are used to define the different metering zones. The split values regulate the position of color boundaries.

External Reference Source: Used to choose reference source material via a drop down menu.

TP: Algorithm choice for True Peak measurement.

Auto Reset: Resets PLR and Program loudness automatically.

Segments: Regulates the number of loudness units represented by each segment on the short-term loudness meter.

Text: Used to adjust the color of text on the interface.

Target: Used to select the target reference

Units: Allows the user to choose LKFS or LUFS (Loudness Units relative to Full Scale).

Send Plug-in: this plug-in is bundled with Master Check and is used to route audio for different scenarios including level matching.

The Master Check feature set is very straightforward, and there are many presets that serve as a good starting point as one delves into the plug-in’s usability.


We tested Master Check in Avid Pro Tools 12 HD Native as a plug-in on our studio’s Windows PC with an Intel Xeon 10-core 2.6 GHz processor. Installation was simple: First, we created an account with NUGEN Audio, and then we downloaded and installed Master Check within minutes. The plug-in used our iLok 2 for authorization.

NUGEN Audio Master Check performed exceptionally well, never caused a crash, and was very light on CPU usage.

We found the workflow within Pro Tools to be a breeze, with easy access to presets, which enabled us to start using Master Check on mixes and masters. All of the presets were accessible from the main screen and allowed to choose based on the standard or digital medium of choice.

The presets were useful, as we could quickly select many useful standards such as streaming mobile, TV, and Apple’s afclip. Additionally, all of the adjustments needed were readily accessible.

Another brilliant characteristic of Master Check is its streamlined design. Specifically, this plug-in is neither bloated nor cumbersome, lacking ornate graphics and sub menus. Moreover, Master Check has a simple interface that is straightforward and almost self-explanatory. We are not suggesting you skip the manual, but most engineers with a basic understanding of metering and mastering tools will get around this plug-in and find good use within minutes.

One excellent way to use Master Check is by placing it at the end of a signal chain. This gave us the option to audition a series of compression and limiting effects while instantly level matching. This was worth its weight in gold because we could base decisions solely on how things sound, without loudness issues clouding our perception. Not to mention, this was a huge time saver since almost all engineers have workarounds to level match, but most of these are far more time consuming than simply using Master Check.

Master Check isn’t just equipped to help mixing and mastering engineers—it can also be very helpful in post-production. Specifically, it deals with the challenge of balancing dialog and music, particularly when the final output will be viewed and listened to on a phone or tablet. Audio quality in these situations is often too poor for clear reproduction. With Master Check, we solved this problem by monitoring the relative loudness of a music and effects bus relative to a dialog bus. This was achieved using the Send plug-in and maintaining a constant dialog-to-music loudness ratio. This works much the same way as the Difference mode works with audio.

Additionally, Master Check provides an excellent solution to the problems caused by the loudness wars. It’s obvious that the designers are well acquainted with the challenges facing mixing and mastering engineers when clients insist upon over-compressed, too loud, masters. This plug-in provides a very practical everyday solution to loudness issues, instantly providing an audio review of how our mixes would sound when processed further by broadcasters across all different mediums. It really makes for an open-and-shut case when it comes to the questions of, “How loud?”


The overall sound quality of Master Check is something to take note of, but not a glaring concern considering the job Master Check is designed to do. Specifically, Master Check is transparent because it is not a tool used to add color or shape sound. It merely reveals what audio will sound like once digital mediums such as Spotify, You Tube or Pandora run loudness normalization algorithms against your prized mix.

Within that context, transparency and true-to-life simulation is what matters. Not surprisingly, in this category Master Check is above reproach. Master Check reveals what an over-compressed mix or master will sound like once normalized for the broadcast medium of choice, and this reference is a priceless commodity when trying to convince a client to leave the dynamics of a recording intact.

Perhaps a better way to make the point is to provide audio examples. In this instance, the following clip shows a mix of Syde Projects’ “Impossible” as it sounds loud ( -9 LUFS) but still dynamic, and then what it will sound like once normalized with Master Checks’ “streaming mobile” preset.

NUGEN Audio Master Check Audio Sample
Loud, but still dynamic.

Honestly, this mix was louder than I had wanted, but the band compromised their original request and went with a manageable level that retained some dynamics. Notice that once normalized for streaming mobile, there was nothing gained by going with this level, but the audio is still not completely crushed.

In contrast, the next example is “Impossible,” almost five decibels louder, but badly over-compressed with no dynamics. Once normalized through Master Check, it would have been easy to convince the band not to go this loud. Check the before and after example.

NUGEN Audio Master Check Audio Sample
Very loud and compressed.

Master Check reveals that once normalized, not only is nothing gained, but the audio is so crushed that the nasty pumping of the compressor is obvious. In short, if a debate about loudness levels with a client does ensue, Master Check will be exhibit A and make an open and shut case to keep your mix quieter and retain dynamics!

Documentation and Product Support

NUGEN has extensive online documentation, including an in-depth user manual. Happilly, the manual is well written and easy to read, though you’ll ultimately have limited need for it since the software is so straightforward.


Master Check sells for $129, which is priced well for any studio. If you’re a working mix or mastering engineer, it’s a tool that can be used every day without hesitation. We consider this an essential studio accessory for anyone in these roles.

Contact Information


Category Value Rating
Features 20% 4 Stars
Usability 25% 4 Stars
Sound 25% 4 Stars
Documentation & Support 10% 4 Stars
Price 20% 3 Stars

Overall: 3.9 Stars, which earns it a WIHO Award!
3.6 stars or better: Outstanding, WIHO Award
3 stars or better: Worth considering
2 stars or better: Suited to specific needs
1 star or less: Not recommended

Evaluation Short-List

Izotope Ozone
Izotope Insight

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