how to filter random noise from an audio signal? How to add pinknoise to audio and how to filter it?

My topic is addition of noise in an audio signal and remove it using suitable filters(I have to design my own filter). I added white noise and random noise in my audio.How can i remove these noise?? My code is:

Fs=160000; [x,Fs]=audioread('youGotmail.wav'); t = linspace(0,(length(x)/Fs),length(x)); subplot(4,3,1),plot(t,x);title('Original signal'); sound(x,Fs); pause(2); y1=awgn(x,33); subplot(4,3,4),plot(t,y1);title('signal with white noise'); sound(y1,Fs); pause(2); z1 = sgolayfilt(y1,3,33); subplot(4,3,5),plot(t,z1);title('filtered white noise'); sound(z1,Fs); pause(2); y2= x + 16*randn(length(x),1); subplot(4,3,7),plot(t,y2);title('Signal with randn noise'); sound(y2,Fs); pause(2);

Also I generated pinknoise but it is not getting added into my audio signal may be due to different length of my audio signal and generated pinknoise. I wrote following code for the geneartion of pinknoise:

hcn = dsp.ColoredNoise('InverseFrequencyPower',1,'SamplesPerFrame',16000); p = step(hcn); subplot(4,3,10),plot(p);title('Pink noise') sound(p,Fs); y3 = x + p; %Error in his line

Also, i want to know is there any other noise which can i add and remove from an audio signal?