When Derek built his home studio, he had a clear plan: carpet everything. Floor. Walls. Ceiling. The door. At one point I think he considered carpeting the desk, but his wife intervened.

Derek's logic was impeccable, in the way that wrong things can sometimes feel very logical. 'Carpet absorbs sound. More carpet equals more absorption. Full carpet equals perfect studio.' He even found a paper online that said carpet had an absorption coefficient of 0.65. He did not notice that this value was measured at 4 kHz.

The result was a room with a reverberation time of 0.15 seconds above 2 kHz — essentially dead, like recording inside a sleeping bag. Below 500 Hz, the RT60 was 1.8 seconds. His mixes were boomy, muddy catastrophes, because the room lied to him about the low end. He compensated by cutting bass in every mix, producing tracks that sounded like they were recorded inside a tin can when played anywhere else.

Carpet absorption at 125 Hz is typically 0.05 to 0.10. That's essentially a mirror for bass frequencies. Derek had created a room that absorbed treble perfectly and reflected bass perfectly — the exact opposite of what a mixing room needs.

The Moral: Absorption is frequency-dependent. Always measure across the full spectrum. SonaVyx's octave band analysis with RT60 comparison would have shown Derek in seconds that his carpet solution only solved half the spectrum — the half that usually isn't the problem.