FiiO R&D made full use of the internal space of the FF3’s housing to fit a bass-enhancing acoustic tube within. This tube extends the airflow path, increases air damping, and improves sound damping to lower the resonance point of the earphones for amazing sound performance. This allows the FF3 to reproduce frequencies as low as 90Hz under normal open wearing [1], and have an effective frequency range down to 42.5Hz for truly deep earbud bass.
[1]Normal earbud wearing refers to conditions without use of a sponge cover.
[2]Effective frequency range refers to the range of frequencies in which the frequency response is not more than 10dB below a certain sound pressure range.
*Above test data are results from FiiO Labs.
*Audio test instruments: APx555B+Brüel & Kjær Head and Torso Simulator (HATS) 4128C.