Clear Filters
Clear Filters

Sound Pressure level returning -inf

2 views (last 30 days)
Hello Community;
when I use the function [Lt,Leq,Lpeak,Lmax] = SPL(recording_vector) it returns vectors containing (partially or completely) -inf values. Surprisingly when I re-Run the same line I get usual numeric values. how is this possible? how to avoid it?
Thanks
  2 Comments
Chunru
Chunru on 2 Sep 2022
Can you show your data (a portion) or your code?
It is likely due to the signal amplitude to be 0 so log of it becomes -inf.
Farid
Farid on 3 Sep 2022
Thanks a Lot Chunru, I am attaching the file to this comment.
calib=importdata('calib.mat')
IRS=importdata('IRS.mat')
spl = splMeter("CalibrationFactor",calib, ...
"FrequencyWeighting","Z-weighting", ...
"TimeWeighting","Fast", ...
"TimeInterval",0.125, ...
"SampleRate",FS,...
"Bandwidth","1 octave");
[Lt,Leq,Lpeak,Lmax] = spl(IRS)

Sign in to comment.

Accepted Answer

Jimmy Lapierre
Jimmy Lapierre on 7 Sep 2022
Leq, Lpeak and Lmax are only computed every TimeInterval, so they correspond to the SPL of zero for the first 0.125 seconds. And as chunru said, that corresponds to -Inf. When you call spl a second time, you are already pass the first 0.125 seconds of pure silence.
To avoid it, either discard the fist 0.125 seconds, or set a minimum value you prefer.
For example set any value below -100 dB (including -Inf) to -100:
Leq(Leq<-100)=-100;

More Answers (0)

Categories

Find more on Measurements and Spatial Audio in Help Center and File Exchange

Products


Release

R2021b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!