Why don’t you answer the question, do you really not know what 120dB below 90dBSPL is? If not, how can we take anything you say seriously?
Certainly! Let’s break down the concept of
Sound Pressure Level (SPL) and calculate the value you’re interested in.
(all the log are base 10)
- Sound Pressure Level (SPL):
- SPL is a logarithmic measure of the effective pressure of a sound relative to a reference value.
- It is expressed in decibels (dB).
- The commonly used reference sound pressure in air is 20 μPa, which is often considered the threshold of human hearing.
- Calculating SPL Difference:
- You mentioned “120 dB below 90 dBSPL.” Let’s find out what this means:
- The difference between two SPL values is given by:
SPL difference (dB)=20⋅log(P1/P0)
where:
- P1 represents the measured sound pressure (in pascals).
- P0 represents the reference sound pressure (typically around 20 μPa).
- Given Information:
- We want to find the SPL difference when the measured sound pressure is 120 dB below the reference level of 90 dBSPL.
- Let’s convert the reference level to actual sound pressure:
- P0 = 20 * 10^(90 / 20) μPa
- P0 = 0.632455532 Pa
- Calculation:
- Let’s find the measured sound pressure P1:
- P1 = 0.632455532 * 10^ (-120 / 20)
- P1 = 0.632455532 μPa
- Result:
- The measured sound pressure is 0.632455532 μPa when it is 120 dB below the reference level of 90 dBSPL.
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I am
not an audio science expert (but I know what is pseudo science). Please let me know if my calculation above is not correct.
I am curious why you
insist to have me to do the calculation? It is done. What you want to show/prove?
To me, our discussion has nothing to do with the correctness of my calculations above.
If you want to show that I don't know what I am talking about if I cannot calculate it correctly, then I would imagine
you don't know the sampling theory as you don't know it works only
under ideal situation.
Real scientist knows the limitations of their experiments.
Not real scientist (aka
pseudo scientist) would take
0.632455532 μPa = 0 μPa and claim they are the same, or in their language "
exactly the same"
==================
To be honest, I really what to know your defintion of the word "perfect" and "exactly"
Question 1:
Do you agree that 0.632455532 μPa and 0 μPa are
exactly the same?
Question 2:
Based on your reply regarding "perfect", it seems that your defintion of "perfect" is not
perfect (pun indeed). People would consider perfect is perfect. There is nothing known as "
absolutely perfect" and "perfect
but not absolutely". To my trained eyes, these "absolutely / not absolutely" are the "art of pseudo science".
You said "
absolutely perfect" below. Does it mean that there is something known as "perfect
but not absolutely"
in your mind?
The Sampling Theorem just requires a band limited signal. In practice we cannot create an absolutely perfect filter with a zero transition band.
Did you apply the concept of "perfect
but not absolutely" in the following reply?
Yes, we did discuss it earlier and you are ignoring that discussion, how is that logical? Perfect can be defined as no audible artefacts, Ie. “Audibly perfect” or “audibly transparent” when using the term “perfect” that is what is typically meant.
Feel free
not to answer if you feel unease about these questions. It is just some food for thought for me (and anyone who are interested in critical thinking)