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A 92dB sound is 50 times as intense as a sound of what loudness?
Wiki User
∙ 14y ago
1.84db?
Wiki User
∙ 14y ago
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Find the problem of sound pressure in Pascals associated with 92dB SPL?
Is there a problem? Reference sound pressure po = 20 µPa = 2×10^−5 Pa (Threshold of hearing). Reference sound pressure level Lpo = 0 dB-SPL (Threshold of hearing level). Get sound pressure p when entering sound pressure level Lp = 92 decibel (dB). Sound pressure p = po×10^(Lp/20) Pa (= N/m²) = 2×10^−5×10^(92/20) Pa = 0.796 Pa.
Your sons hearing test shows 70dB to 92dB how much hearing does he have?
The answer to this question includes a number of complex variables. The following is a thumbnail sketch of the variables.A hearing loss means that at any given frequency (think pitch, like a note on the piano) you need more sound pressure (think volume) than someone with good hearing. You require a louder sound before the inner ear can send a noticeable signal to the brain. Audiometric Scale. The numbers you provided, 72 dB to 90 db, are numbers from an audiogram. The audiogram is a graph or chart that records your response to sound presented to the ear. This sound is presented in frequencies (notes) typically starting at 500 Hz. You are then tested in the following frequencies 1K, 2K, 3K, 4K and 6K. That is a basic sequence often followed. A more thorough test will start at 125 Hz and go all the way to 8K, testing each octave and some ½ octaves along the way. Zero on this scale is not an absolute number; it does not mean there is no sound being presented. It is a number derived from an average of many thousands of tests. It is the softest level at which someone with perfectly good hearing can hear a given frequency. If your hearing level is higher than zero, say 10 dB, 40 dB, 70 dB, then, this is the additional amount of energy your ear needs to hear a sound. It is the additional amount over someone with very good hearing. The audiometric scale ranges from -15 dB to about 140 dB, the point at which your ears are likely to start bleeding. Anything above 85-90 dB, over a given period can be harmful to your hearing. The louder the sound the lower the time exposure before damage occurs. Frequency Trivia. 250 Hz is approximately middle "C" on the piano. 4K is the high note on the piano. 29 Hz is the low note. The audiometric scale does not tell you how much speech understanding you have. It only tells you the sound pressure level needed in order for you ear to send a signal to the brain. The brain needs more energy and much more information than that to understand speech. The audiogram only gives us a general idea of how difficult it is for a person to hear a sound. Included in this series of the tests we also conduct "Bone Conduction" tests and frequency specific LDLs. (tonal loudness discomfort levels). SRT, Speech Reception Threshold. This is the first in a series of speech tests that we give to help determine the answer to the question "how much am I hearing". When someone asks, "how much hearing do I have?" They typically are wonder how much of the conversation are they getting, or missing? The SRT gives us the level at which sound is loud enough for you to begin understanding words. A typical SRT for someone with excellent hearing is as low as 5 dB. A typical SRT for anyone over the age of 40 is about 15-25. An SRT range that we would normally expect to see for someone with a 70 dB to 90 dB loss will run from 70 to 105. That is a wide range because it is dependent of the actual damage present in the cochlea (inner ear). The SRT range depends on more than just the SPL presented. Speech understand also depends on more than just the SPL (sound pressure level, think "volume"). Speech understanding depends on the coordinated function of thousands (approx 30,000) of nerve endings we call hair cells, in the inner ear. Of course it also depends on the entire nerve path and the respective brain areas. But in the vast majority of hearing losses (say 90%) the problem is in the inner ear. The speech reception testing sequence also includes tests for the MCL (most comfortable level) and the LDL or UCL (loudness discomfort or Uncomfortable levels) The next phase of testing will more directly assess your speech understanding. This portion of the testing sequence includes the tests we call "Discrimination testing". It also includes "Speech In Noise" testing and "Master Hearing Aid" testing. In summary the 70 to 90 dB loss provides only a small glimpse of a persons hearing function. With those two numbers, I do not know which frequencies were tested. For instance if this loss occurs at 6k Hz and 8k Hz (a common occurrence) the patient being tested might show 80% or better speech understanding. On the other hand if the loss is a flat loss starting at 70 dB (at 250 Hz) and declining to 90 dB (at 6k Hz) then the persons speech understanding could be 30% or lower. Of course speech understanding cannot be derived from the audiogram. It requires actual speech discrimination testing. True I can make a fairly educated and experienced guess, but a wide range of answers is possible.
