I want to do a 1/3rd Octave band analysis on a noise signal. But the sound pressure levels should be in dB(A), i.e., and it should be A-weighted. For this, I am using the A-weight function from this module.
From this link, what I understood is that the function A-weight takes the input as a signal(in Pressure(Pa)), and sampling frequency and gives the output as another signal(in Pressure(Pa)). If This output signal converted into pressure level should provide the A-weighted pressure levels.
Now, I use the A filtered sound pressure signal as my starting point and use the Butterworth filter to convert it into 1/3rd Octave Bands. Reference for this - https://stackoverflow.com/questions/56791652/1-3-octave-from-audio-file-with-python
The method I am using is not giving correct results in the lower bands, and I cannot figure why. I don't want to use the weights directly as I want a generally weighted signal for purposes other than just 1/3rd Octave Band Analysis too. I am a beginner in DSP so that any help will be much appreciated. Feel free to suggest even alternative approaches for the A-weighting filter that can be executed in Python. Thank you