Masking Flashcards
What is Masking
The process by which the threshold of audibility for one sound is raised by the presence of another.
Signal = sound of interest (Tone A), Masker = the interfering sound
Describe partial masking
Partial masking: the reduction in loudness that can occur when a second sound is presented
What are other important aspects of masking
Threshold for tone A= 1kHZ at 5 dB SPL
Sound B is introduced and the threshold for Tone A is measured in the presence of Sound B. The new tone A threshold = 15 dB SPL( a.k.a, the masked threshold).
Threshold for Tone A increased given that there was a decrease in sensitivity to Tone A
Describe Tonal Masking
Tonal masking: the masker is a tone
-Effective maskers are at frequencies that are close to the center frequency of the signal. The greater the frequency difference between the signal and the masker, the greater the intensity of the masker must be to mask effectively.
Tonal Masking: Intensity- Masking increases as the intensity of the masker is raised
What is Noise Masking
the masker is some type of noise
Describe the Upward Spread of Masking
Masker tones that are lower than the signal frequency do a better job of masking the signal
Masker tones that are higher than the signal frequency are less effective. Thus, a masker of a given frequency masks higher frequency signals more than lower frequency signals which is called “upward spread of masking”
When signal and masker are very close in frequency, you get beats
What is Noise
when you combine a very large number of pure tones, where the individual frequencies do not share a mathematical relationship.
Describe Noise Masking
Less easily confused with pure tone signal and doesn’t cause beats. As the spectrum level of white noise is raised, overall threshold for signal detection rise
What are various types of noise maskers
White noise (White Band Noise)- contains a wide range of frequencies thus it masks tones of many different frequencies. Narrow band noise:- Noise is specifically centered on frequency of signal of interest
Describe Simultaneous Masking
Signal and masker are presented at the same time, tone on tone and noise on tone
Describe Temporal Masking
Time- signal and masker need to be presented within less than 50-100 ms of each other to show masking effects.
Describe the types of temporal masking
Forward Masking: Masker occurs before signal
Backward Masking: Masker occurs after the signal
Simultaneous Masking: Masker and the signal occur at the same time, or the signal is temporally presented in the middle of the masker.
