#230: What Is a Null Test? Stop Guessing Your Mix Changes with Eric Mitchell

Null testing is one of the fastest ways to prove what actually changes in a mix. In this episode of Inside The Mix, Marc Matthews sits down with mastering engineer Eric Mitchell to explain what a null test is, how phase cancellation works, and how producers can use null testing to stop guessing and start making confident decisions.

Built for beginner to intermediate music producers, this conversation answers common questions like: What is a null test in audio? Do similar plugins really sound different? Can meter settings or power conditioners affect digital audio? Marc and Eric walk through real-world null test examples, flipping polarity, aligning samples precisely, and listening only to what doesn’t cancel.

Together, they put popular studio myths to the test. Do plugins built on the same code cancel perfectly? Can DAW meter scaling change your sound? Does file integrity survive cloud storage and drive transfers? Eric shares clear results and a calm framework for evaluating bold claims without getting lost in internet noise or expectation bias.

Listeners also learn how to run a null test step by step: use identical source files, line them up sample-accurately, invert polarity, and expect differences more often than silence. The episode covers the limits too, why analogue passes won’t fully null, and how to use measurements to support musical taste rather than replace it.

If you’re tired of second-guessing mix choices or buying duplicate tools, this episode shows how null testing can save time, money, and mental energy.

TL;DR: Null testing uses phase cancellation to reveal real differences between audio files. Marc Matthews and Eric Mitchell explain how to run null tests, bust audio myths, and make confident mix decisions backed by evidence

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