In what kind of room is reverberation more likely to mask high frequencies?

Reverberation occurs when sound waves reflect off surfaces in a room and create persistent echoes. In a small room, such as one that is 17 meters or less, the dimensions allow for sound waves to bounce off the walls, ceiling, and floor in a way that can create a dense layer of reflected sound. High-frequency sounds, which are shorter in wavelength, are more susceptible to being masked by these reflections, as they may not dissipate as quickly as lower frequencies.

In a small room, the proximity of reflective surfaces can lead to rapid build-up of reverberant sound, causing high frequencies, which can be more directional, to be less distinguishable against the background of continuous sound. Conversely, larger spaces tend to allow sound waves to disperse more effectively and often have less problematic reverberation for high frequencies. Similarly, soundproof chambers are designed to minimize reflections, thus preventing masking of any frequencies.

Because of these dynamics, a small room is indeed where reverberation is more likely to interfere with the perception of high-frequency sounds.