sgolayfilt function not smoothing

In the below code I am attempting to plot an audio file in the frequency domain using FFT, and then smooth out the frequency response with sgolayfilt, however the filter is not working. As a beginner, I'm not sure where to go next and would appreciate any help!

[y,Fs] = audioread('Floor_EQ_ITB.wav');

Fn = Fs/2; % Nyquist Frequency

fty = fft(y)/length(y); % Take FFT & Normalise

fv = linspace(0, 1, fix(length(fty)/2)+1)*Fn; % Frequency Vector For Plot

iv = 1:length(fv); % Index Vector For Plot

filt = sgolayfilt(fv, 5, 501);

figure(1)

semilogx(filt, 20*log10(abs(fty(iv))))

xlabel('Frequency (Hz)')

ylabel('Amplitude (dB)')

set(gca,'XLim',[15 20000],'XTick',[0 31 62 125 250 500 1000 2000 4000 8000 16000])

[Image Analyst]

Please zip up 'Floor_EQ_ITB.wav' and attach it.

[Barny Cutter]

Too large to attach but available here

[Shrey Joshi]

Try using signalAnalyzer app in signal processing toolbox.You can preprocess signal using sgolayfilt and visualize its spectrum

https://www.mathworks.com/help/signal/ug/using-signal-analyzer-app.html