Do digital slr cameras use fake sound for shutter clicks?

the sound sure is loud. didnt know if it was a natural sound or if cannon digitalizes the sound for effect. and if so how to turn it off or down?

To the best of my knowledge, only point & shoot cameras use fake sounds.
On a dSLR, the shutter makes a very muted click but the mirror slap can create a pretty loud noise. Loud enough for judges to ban (digital) SLR cameras from court rooms (Leica rangefinders and point & shoot cameras, only), for people to throw you irritated glances in theaters, and to give you away when you're taking candids up close.
There's not a lot you can do about it. It's purely mechanical and neccessary for the camera to operate. But some models are worse than others. The Canon 10D and 20D are less noisy than the 30D, for example.
The only way to muffle this sound in to encase the camera in a 'blimp'. Or you could use mirror lock-up, but on digital SLR cameras this is a shot-by-shot setting - so that would only give you one stealthy picture.
Sorry. There's no off button.

Hmm, I don't know. I have a Nikon, and it sounds normal. Do you mean the electronic beeps? Those are added, and you can turn them off using your camera's menu options.

I stand corrected........ I guess that's what I get for answering without fact-checking. I have so many cameras that make that click where I have turned it off, I just thought my SLR's were that way also. I just checked two of them and there's no noise but the mirror slap. I'm looking at Nikon's though, so please accept the other answers over mine. OMG has mentioned some Canon's specifically and Koko can certainly tell us if this is a feature on his XTi or not.

Well it doesnt make a fake mirror slap for sure on Canon models. It does make a beep when it focuses and it has your subject in focus but thats all the noise it makes. I dont recall reading anything in my manuel about turning on fake beeps.

The only beep is the when the auto focus is focusing on a subject. Besides from that, no what you hear when the "slap" is just the mirror.

No, you are a very funny person. That is not a digital sound. That is the sound of the mirror in the camera flipping so that the image can pass the CMOS (complementary metal oxide sensor) so that the camera can actually take the picture. So, in turn, the sound is not fake, it's real, so you can't turn it down.