Gender and speech material effects on the long-term average speech spectrum, including at extended high frequencies

Gender and language effects on the long-term average speech spectrum (LTASS) have been reported, but typically using recordings that were bandlimited and/or failed to accurately capture extended high frequencies (EHFs). Accurate characterization of the full-band LTASS is warranted given recent data on the contribution of EHFs to speech perception. The present study characterized the LTASS for high-fidelity, anechoic recordings of males and females producing Bamford-Kowal-Bench (BKB) sentences, digits, and unscripted narratives. Gender had an effect on spectral levels at both ends of the spectrum: males had higher levels than females below approximately 160 Hz, owing to lower fundamental frequencies; females had [~]4 dB higher levels at EHFs, but this effect was dependent on speech material. Gender differences were also observed at [~]300 Hz, and between 800-1000 Hz, as previously reported. Despite differences in phonetic content, there were only small, gender-dependent differences in EHF levels across speech materials. EHF levels were highly correlated across materials, indicating relative consistency within talkers. Our findings suggest that LTASS levels at EHFs are influenced primarily by talker and gender, highlighting the need for future research to assess whether EHF cues are more audible for female speech than for male speech.