Final answer:
The absence of frequencies below 600Hz can greatly impair the clarity and understanding of speech due to the crucial role that these frequencies play in conveying the characteristics of speech sounds.
Step-by-step explanation:
The absence of frequencies below 600Hz adversely affects the intelligibility of speech. This is because normal human hearing encompasses frequencies from 20 to 20,000 Hz, with most conversational sounds falling within a certain frequency and intensity region. Hearing losses, measured in phons, can drastically impact one's ability to comprehend conversation. For instance, a 60-phon hearing loss at all frequencies means that only the lowest frequencies are heard, making speech seem indistinct due to the lack of higher frequencies being well perceived. This can be more problematic for understanding higher-pitched voices, like those of females, due to the higher frequency characteristics of such voices.
The perception of frequency as pitch and intensity as loudness are central to understanding how we hear. Frequencies below 20 Hz are termed infrasound and those above 20,000 Hz are ultrasound, both of which are outside the normal range of human hearing. However, speech relies primarily on a range of frequencies much narrower than this, typically between 250 to 8000 Hz, with essential speech elements residing in the lower frequencies that include below 600Hz.