Go to the settings for your webcam. The voice effects may be turned on. I had this problem with my dell laptop.
Why Does My Voice Deep Come Out Deep On Skype To The Person At The Other End? How Can I Change It?
Well generally this is not the problem in Skype as I have used in many times but you need to check its settings may be due to echo it is altering your sound that look different on the other end. Just go to sound settings where you can adjust to standard settings.