The biquadrate BIH filter model.
The Biquad Filter unit independently filters each channel of the input signal using the specified biquad filter with infinite impulse response (BIH). When you specify the filter coefficients in the parameter settings window, the block implements static filters with fixed coefficients.
The recorded noisy audio signal is fed to the input of this filter, and at the output we receive a filtered signal.
Let's move on to the implementation of this project: we will define auxiliary functions and build a model.
Let's define the player's function.
Pkg.add("WAV")
using WAV;
using .EngeeDSP;
function audioplayer(patch, Samples_per_audio_channel);
s, fs = wavread(patch);
buf = IOBuffer();
wavwrite(s, buf; Fs=fs);
data = base64encode(unsafe_string(pointer(buf.data), buf.size));
display("text/html", """<audio controls="controls" {autoplay}>
<source src="data:audio/wav;base64,$data" type="audio/wav" />
Your browser does not support the audio element.
</audio>""");
return s
end
Let's connect the auxiliary function of launching the model.
function run_model( name_model)
Path = (@__DIR__) * "/" * name_model * ".engee"
if name_model in [m.name for m in engee.get_all_models()] # Checking the condition for loading a model into the kernel
model = engee.open( name_model ) # Open the model
model_output = engee.run( model, verbose=true ); # Launch the model
else
model = engee.load( Path, force=true ) # Upload a model
model_output = engee.run( model, verbose=true ); # Launch the model
engee.close( name_model, force=true ); # Close the model
end
sleep(5)
return model_output
end
Let's build and run the models.
Single-channel model:
Multi-channel model:
run_model("Biquad_filter") # Launching the model.
run_model("Biquad_filter_multichannel") # Launching the model.
After running the model, we can see which frequencies were filtered out in the single- and multi-zone variations of the model.
Now let's listen to the input and output signals.
audioplayer("$(@__DIR__)/MysterySig.wav", 256);
audioplayer("$(@__DIR__)/output.wav", 256);
audioplayer("$(@__DIR__)/output_multichannel.wav", 256);
Conclusion
As we can hear and see, the filter works correctly and allows you to get rid of extraneous noise in the original audio signal.