×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

#### Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

# generate echo with convolution and cancel it

## generate echo with convolution and cancel it

(OP)
hello guys

i am beginner at using matlab

i want to generate echo on a sound file i recorded in wav and then made echo on it with convolution method.

and the second part cancel the echo

i dont know how to do it in matlab , i know formulas only .

any help i will be thankful

thx

### RE: generate echo with convolution and cancel it

(OP)
thx :)

i have this code for do echo:

#### CODE --> matlab

%working code for echo in conv

x = zeros(1000,1);
x(1) = 1;
x(1000)=1;

z= conv(x,y);
sound (z,Fs); 

i want remove the echo from the sound and get back original sound but with using convolution method only??!!

i tried this method

#### CODE --> matlab

%cancelling

N=25199; % delay in samples

y=z; % Signal with echo

x(1:N)=y(1:N); % First N samples of x and y agree

for i=N+2:length(y)

x(i)=y(i)-0.75*x(i-N); % Inverse filtering

end

subplot(211)

plot(y); % Plot signal with echo

title('SIGNAL WITH ECHO');

subplot(212)

plot(x); % Plot signal without echo

title('SIGNAL WITHOUT ECHO');

soundsc(y); % Listen to signal with echo

soundsc(x); % Listen to signal without echo 

x sound only same as echo one and when reduce N samples to less .... there is echo come over the original one

any help plz??!!!

### RE: generate echo with convolution and cancel it

(OP)
yeah , it a project

i have a work code for cancel the echo:

#### CODE --> matlab

l=max([length(z);length(x)]);
a=fft([z;zeros(l-length(z),1)]);
b=fft([x;zeros(l-length(x),1)]);
c=real(ifft(a./b));
sound(c,Fs); 

it works fine , but they want me use conv function to remove echo , i dont know how :\

#### Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

#### Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

#### Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a partâ€™s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!