SPL Noise Contour plots
SPL Noise Contour plots
(OP)
Hi everyone,
I'm have an array of microphones (13 x 17) measuring pressure over a certain time period. I want to create a sound pressure level contour (SPL) plot from the pressure time histories for frequencies in the range (416 - 2,780 Hz). If I apply a fourier transform of the pressure time histories for SPL, I get a range of [dB] values for the associated frequency range but I only want 1 value per microphone in order to create my contour plot. A paper I have referenced says the pressure time histories should be frequency averaged. What does this mean?
Can anyone help me with this problem?
Thanks for any help.
Regards,
Stephen
I'm have an array of microphones (13 x 17) measuring pressure over a certain time period. I want to create a sound pressure level contour (SPL) plot from the pressure time histories for frequencies in the range (416 - 2,780 Hz). If I apply a fourier transform of the pressure time histories for SPL, I get a range of [dB] values for the associated frequency range but I only want 1 value per microphone in order to create my contour plot. A paper I have referenced says the pressure time histories should be frequency averaged. What does this mean?
Can anyone help me with this problem?
Thanks for any help.
Regards,
Stephen





RE: SPL Noise Contour plots
RE: SPL Noise Contour plots
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: SPL Noise Contour plots
I'm measuring the noise generated form a model helicopter on a CFD software. After reading their results again, I realised that they averaged the frequency over a number of revolutions of the rotor blades to eliminate any random portions of the signal whereas I only measured the acoustic signal for 1 revolution. Sorry for any confusion.
I am still confused about how to generate my contour plots. I get very different values when I calculate the SPL using the RMS conpared to the values generated by the software.
The software seems to be taking the max SPL at each microphone to create the contour plot. Is this logical?
RE: SPL Noise Contour plots
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: SPL Noise Contour plots
Combined dB = 10log(10^(dB1/10) + 10^(dB2/10) + ....... + 10^(dBn/10))