Max spl question

[jadenlinkletter]

p=Sd*Xmax*f^2*pi*rho0/(r*sqrt(2))

i know what everything in there means, but what the heck is "sqrt(2))"

some advice?

[dooper]

1.4142...also expressed as 2 ^ 0.5. In English, the square root of two.

dooper

[GM]

The square root of 2, or 2^0.5 = ~1.4142.

GM

[jadenlinkletter]

P value is 5.8304
formula sais:

20*log 10(5.8304/0.00002) = spl

when i type 20*log 10 in my calculator, i got 20

multiplied by (5.8304/0.00002)

is 5830400.

DOES NOT MAKE SENCE. SOMEONE HELP

[dooper]

I get about 109.3 dB.

In Windows calculator - scientific view:

5.8304/0.00002 = 291520

With 291520 in the window, click log

Result is 5.4646683552929042237014952913997

Multiply that by 20 -> 109.29336710585808447402990582799

I'm sure someone will correct me if this is incorrect.

HTH,

dooper

[454Casull]

Does the r represent radius?

[jadenlinkletter]

r represents distance in meters from the microphone

[DonoMan]

20*log 10(5.8304/0.00002) = spl
when i type 20*log 10 in my calculator, i got 20

Log 10 means base 10 log. If log 10 = 1 in your calculator, then it is base 10. So just do log(5.8304/.00002). If log 10 shows something else (it doesn't show something else in your case, but for others, it may), then your log is not base 10. You can make it base 10 by doing this:

base b log of n = log(n) / log(b)

That'll work even if you're already in the correct base log.. You can get from base e to 10 or 10 to e easily that way, but you can pick any number you want.. You can do base 72.971 that way if you like.