The human auditory system has a remarkable range of sensitivity, but the perception of sound is subjective and can vary from person to person. In general, the threshold of hearing is considered to be around 0 decibels (dB) sound pressure level at a frequency of 1,000 Hz for an average young adult with normal hearing.
However, it's important to note that 0 dB does not mean the absence of sound. It represents the softest sound that an average human with normal hearing can detect. As the sound level decreases below 0 dB, it becomes increasingly difficult for most people to perceive the sound.
When it comes to the perception of small changes in sound intensity, it becomes more challenging. Studies suggest that the smallest noticeable change in loudness, known as the just noticeable difference (JND), is generally around 1 to 3 dB for most people. This means that, on average, a change of about 1 dB is the smallest difference in sound level that can be detected.
So, while it is theoretically possible to hear a difference of 1 dB, it may not be noticeable to everyone, and it depends on various factors such as the individual's hearing acuity, background noise, and the frequency of the sound.
It's also worth mentioning that the perceived loudness of a sound is not solely determined by its intensity in dB. Other factors, such as the frequency content, duration, and the individual's auditory sensitivity, can influence how loud a sound appears to be.