## amplitude_vsfrequency.jpg

The image is a graph titled "Thresholds and upper range of hearing as a function of frequency in humans." It illustrates how human hearing sensitivity varies with different frequencies (measured in Hertz) and sound pressure levels (measured in dB SPL). The x-axis represents the frequency, ranging from 10 Hz to 10,000 Hz. The y-axis shows the sound pressure level, ranging from -20 dB SPL to 140 dB SPL.

The graph includes several key points:
- **Threshold of Hearing**: This is indicated by a dashed line that starts at approximately 20 dB SPL and rises as it moves up the frequency axis.
- **Threshold Reference Levels based on ANSI (2010)**: These are represented by closed circles along the threshold of hearing curve. They show higher sound pressure levels required for different frequencies to be audible, especially in the lower and upper ranges of human hearing.
- **Threshold of Pain**: This is marked at 140 dB SPL across all frequencies on the graph.

The shaded area between -20 dB SPL and approximately 60 dB SPL represents sounds that are not typically audible by humans. The text "Sound not audible to human ear" is placed within this shaded region for clarity.

There are no people or characters in the image, only a scientific representation of auditory thresholds and reference levels.

This description was generated automatically from image files by a local LLM, and thus, may not be fully accurate. Please feel free to ask questions if you have further questions about the nature of the image or its meaning within the presentation.