Is there a formula for calculating SPL?

AI Thread Summary
The discussion revolves around calculating Sound Pressure Level (SPL) using the formula SPL = 20 log(p/pref), where pref is the reference pressure of 20 micro Pascals. Participants clarify that 'p' represents sound pressure, and if either SPL or pressure is known, the other can be calculated. A participant initially misapplies the logarithmic function but later confirms that an acoustic pressure of 200 micro Pascals results in an SPL of 20 dB. The conversation highlights the importance of understanding logarithms in sound technology. Overall, the thread emphasizes the relationship between sound pressure and SPL in audio calculations.
Chantelle
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Hi. Is there a formula for calculating SPL?

The information I have is Frequency of pitch, dB level of pitch and 0dB as 20uPa.

TIA
 
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The reference pressure level (pref), which defines the threshold of hearing for an average healthy person, is 20 micro Pascals. That pressure is the 0 dB SPL. Other values are computed as:

SPL=20 log(p/pref)
 
Thanks, howvere, at risk of sounding completely stupid what is or what value is p?
 
If you know the pressure, you can compute the SPL. If you know the SPL, you can calculate the pressure. If you know neither of them, you're in serious trouble.
 
I think I probably am! :)

Looks like its the sound pressure i need.

Do you think this is correct?

Source is 20dB and pref is 20uPa

Sound pressure = 20 x 10^(20/20) = 200uPa??

Thanks for your time and help x
 
I said SPL=20log(p/pref)=20log(20/20)=0 dB
You used the inverse function.
Are you acquanteid with logarithms?
 
No. I'm a musician doing a course in sound technology :( x
 
My apologies, I meant no offense. By the way, your example was right. When I read it I was too tired and I misunderstood what you had written. If the acoustic pressure is 200 micro Pascals the SPL is 20 dB indeed.
 
No offence taken at all. Very grateful for your help, thankyou x
 

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