Filtering the Matlab audio signal

How can I implement filtering of a noisy real signal using only code? When working with harmonic signals, everything is simple and everything works. Due to the fact that the real signal is much larger, matlab does not miss the work of the code. The code for the harmonic signal is attached below. To solve this problem, I used audioread to read the signal, as well as normalize the signal and noise with imnoise, and then, when creating the matrix A, the program breaks down, since 79380x79380 is required.

clc
clear

Fsample = 1000; %Частота дискретизации
f = 20; %Частота колебаний
t = 0:1/Fsample:2; % Временная ось
x1 = sin(2*pi*f*t); % Гармонический сигнал
x3 = x1 + randn(size(t)); % Гармонический сигнал с шумом
figure(1), plot(t,x1), title("Гармонический сигнал")
figure(2), plot(t,x3), title("Гармонический сигнал с шумом")

v1 = 0.0380*pi;
v2 = 0.0423*pi;
N=length(t);
A=zeros(N,N);
for i=1:N
   for k=1:N
        if(i==k)
            A(i,k)=(v2-v1)/pi;
        else
            A(i,k)=(sin(v2*(i-k))-sin(v1*(i-k)))/(pi*(i-k));
        end
    end
end
y=x3*A;
figure(3),plot(t,y), title("Выходная последовательность после оптимальной фильтрации");

It must be converted to an audible signal.