make a vector from wave sound

 [x,fs,nbits] = wavread('w.wav');
 %sound(x,fs);
 h = zeros(1,4000);
 h(1) = 1; 
 h(1000) = 0.25; 
 h(2000) = (1/16);
 h(3000) = 1/64;
 h(4000) = 1/256;
 y = conv(x,h);
 y = y/max(y);
 sound(y,fs);

it gives me an error "A and B must be vectors" as for y = conv(x,h) .

Answer 1

[Star Strider]

Check the size of ‘x’. It may be a two-column matrix (one column for each channel).

[ayman daraghmah]

yes it's two-column matrix. Do i need to use 2D convolution ?

[Star Strider]

Not strictly 2D but do the same convolution on both channels, or if the same sound is duplicated in both channels, just one column of ‘x’ with your current code.

[Image Analyst]

You could do one 2D convolution or 2 1-D covolutions

rightChannel = x(:, 1);
echoRight = conv(rightChannel, h, 'same');
leftChannel = x(:, 2);
echoLeft = conv(leftChannel , h, 'same');
% Combine
newSignal = [echoRight, echoLeft];

or something like that.

Answer 2

[Image Analyst]

Maybe try

y = conv2(x, [h,h], 'same');

or

y = conv2(x,[h;h], 'same');

so you're doing a 2D convolution