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Please find the attached source code file and audio file * .wav file.

I would like to filter out the impulse noise from the right channel.

Adam Danz
on 11 Feb 2020

Edited: Adam Danz
on 12 Feb 2020

This uses findpeaks to locate the impuse signal in channel 2 of the wave file. Peaks are required to be at least 3 standard deviations larger than the mean signal. The values are replaced with the median of that channel (excluding the impulse signal). fFilt is the filtered version of f.

% Read in wav file

FileName = 'rec_noise.wav'; %full path is better

[f,fs] = audioread(FileName);

% Locate peaks

minHeight = mean(abs(f(:,2))) + std(abs(f(:,2)))*3; % min height to be 'peak'; 3 std above mean

[pks, locs] = findpeaks(abs(f(:,2)), 'MinPeakHeight',minHeight);

pks = pks .* sign(f(locs,2)); % pks is only used for plotting

% Replace peaks with the median value of f(:,2) expluding outliers.

% You could also just remove those values but you'd need to remove them in chan 1, too.

isOut = ismember(1:size(f,1), locs);

replacementValue = median(f(~isOut,2)); % you could also use NaN, 0, etc....

fFilt = f;

fFilt(isOut,2) = replacementValue;

Plot the results.

clf()

% Plot channel 1

sp(1) = subplot(3,1,1);

plot(sp(1), f(:,1),'DisplayName','chan 1')

title(sp(1), 'channel 1')

% Plot channel 2

sp(2) = subplot(3,1,2);

plot(sp(2), f(:,2),'DisplayName','chan 2')

title(sp(2), 'channel 2')

% Show outliers (impulses)

hold(sp(2),'on')

plot(sp(2),locs, pks, 'rx', 'DisplayName', 'Outliers')

% Plot the filtered channel 2

sp(3) = subplot(3,1,3);

plot(sp(3), fFilt(:,2),'DisplayName','chan 2 Filtered')

title(sp(3), 'channel 2 filtered')

linkaxes(sp)

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