Week 2.1 Flashcards
What is a prescriptive formula?
A way of telling us how much volume someone needs.
What are the two different types of prescriptive formula? Give an example of each.
Supra threshold based prescriptions: DSL i/o
Threshold based prescriptions: NAL
What are targets?
Where average individual w/a hearing loss needs volume of HI to be in order to achieve the goal of the prescriptive formula
How do you determine where targets fall?
- severity of hearing loss
- specific formula used
- monaural or binaural hearing
- conductive component
- congenital or acquired
What are the most common prescriptive formulas, and what are their goals?
NAL: national acoustic library. Goal is to maximize speech intelligibility. Preferred by adults.
DSL: desired sensation level. Goal is to normalize loudness. Preferred for children.
What are the four stages of DSL m [i/o]
- Expansion: takes soft input and squishes it so it won’t mask speech.
- Linear amplification: 1:1
- Compression: 1 dB inpud :
What are some issues with prescriptive formulas?
- Acclimatization
- Preferred loudness levels
- Dead regions
- Severe to profound HF HL
What is a dynamic range?
The range of sounds that a given individual can hear.
What is compression:
Output range smaller than input range.
What is a compression threshold?
Input level where compressor switches from linear amplification to non-linear amplification
What is multichannel compression?
Since HL varies by frequency, must have different compression ratios and thresholds.
What is the most common form of compression?
Wide dynamic range compression, gradual application of compression over a wide range of input signals.
Why do attack and release times exist?
To protect against abrupt input changes, ensuring no over-amplification and that all sounds are still heard
What is an attack time?
The time it takes for compression to kick in. Range from 5ms to 20 ms.
What is release time?
Time it takes compression to turn off, randong from 20ms to 2 s.
