What do you think about the method of mixing & mastering that involves applying a high-pass filter to the master track to cut off the ultra-low frequencies?

Applying a high-pass filter to the master track to cut off ultra-low frequencies can be effective in some aspects of music production. However, this depends on the genre of music and its intended purpose.

One reason to cut off ultra-low frequencies is to reduce wasted energy and increase headroom. Specifically, ultra-low frequencies that are hard to hear can cause a large movement in speakers, so cutting these frequencies allows you to focus energy on other important areas of the audio spectrum.

However, completely cutting these low frequencies could potentially lose the punch and power in genres like electronic music and hip-hop. Also, high-end audio systems and club sound systems are capable of reproducing these ultra-low frequencies, and the absence of these frequencies may compromise the musical experience.

Therefore, caution is needed when cutting ultra-low frequencies. It’s important to choose an appropriate frequency for the cut-off, and also to select the slope of the high-pass filter (either a steep cut-off or a gradual one).

Moreover, instead of using a high-pass filter during the mastering phase, you might consider applying it to each individual track during the mixing phase. This allows for more fine-tuned control over the characteristics of each instrument. By applying it during the mixing phase, you can remove unnecessary low frequencies while maintaining important bass components.

This technique can be effective in many aspects of music production, but it is not an absolute rule, so caution is needed. Ultimately, the judgment needed is to provide the best experience for the listener.