The worst mastering technique you will ever hear about.
Spectrum EQ curve matching.
There's been a craze online and especially in the electronic scene about EQ curve matching during mastering, especially by producers as well as online services such as LANDR, boasting about their cookie cutting algorithms. Claiming that analysing, comparing and developing an equalisation curve based on a set of professionally mastered songs can transform your mix along the lines of your favourite tracks.
The logic is very simple. If the particular frequency response on a spectrum analyser sounds good on comparison material, your mix will present in a similar fashion when equalisation is applied to match that analysed frequency response. We clearly see how attractive in theory the concept is, and how it deceives many people to hop on the bandwagon. But sadly, in reality, the concept is flawed, and here's why.
The key of the song. Even with a wide/broad Q bandwidths, boosts and dips must always be sympathetic to the key of the song. Curve matching doesn't compensate for the subtleties of key variation between the reference material and the mix. Boosting frequencies that are conflicting and dipping frequencies that are complementary to the key of a song is a recipe for disaster.
The tone of individual instruments. The sound of each instrument in a mix will spread across many octaves of the frequency spectrum. Different instruments, recordings, performances and samples all have unique waveforms which are presented differently on a spectral analyser, and this is especially notable when a collection of signals get summed together. No two sets of combinations are identical. Cookie cutting a curve from a set of comparison tracks isn't going to result in a curve that is sympathetic to the unique harmonic structure of your mix.
No two songs are identical. That's what's beautiful about music and art. During mastering, you have a final opportunity to assess and ensure you're music translates across to the listener. Knowing it's unique you should seek to create a final master that doesn't copy your references but becomes the track that inspires other artists to use as a comparison and reference point.
Before I conclude, I would like to leave you with some food for thought and something for you to take into your next session. Referencing is not comparing. Comparing can undermine your artistic values, goals and music's potential. Referencing is still valuable to develop a mix, concepts and train of thought. Use references to identify both desirable and undesirable elements in what you're working on, then devise a game plan to process your audio respectively.