I have a Nikon D3300. When I take a photo, it makes one sound than after two seconds, it makes one more sound. This thing irritates me because I can't take photos rapidly and I have to wait for 2-3 seconds for every shot.
Make sure you don't have live view on.
Live view is a camera mode where you are able to view the camera's current POV much like the eyepiece, except that you are able to simulate your exposure settings / software optical filters (such as sepia and contrast/white balance enhancement) on screen (assuming your camera has a screen).
If live view is on, you will not able to see through your eyepiece when taking a photo and every time you take a photo, the shutter has to:
pop out of live-sensor mode, into the eyepiece to start from scratch
take the photo (pop back to the CMOS sensor for your exposure time).
quit sensor exposure by popping back to the eyepiece
snap back to live mode after a couple seconds (this would be the noise you speak of, kind of like opening to an infinite exposure)
Live view itself is partly a limiting feature of the camera when it is on in that, you will not be able to take another photo until it "snaps back to live mode". This process takes a few seconds because the camera is still storing to memory the first photo you took, and won't start live mode again until this has completed.
If you are knowingly using live view but still want to take multiple photos quickly, you may be able to use your camera's
It always make two sound (four, to be precise). The first (pair) one is a mirror hitting upper limit (and shutter opening) to free the path to the sensor and the second (pair) one is the mirror hitting the lower limit to reflect the light in the prism (and shutter closing).
If the shutter speed is fast enough you cannot notice these two (four) sounds as individuals but you hear one smash.
If the shutter speed is slow enough, from 1/10 s to bulb, you can distinguish these two (pairs of) souds. Time delay between mirror up and shutter open is imposible to hear.
The reason you cannot shoot faster than frame per 2-3 seconds may be caused by the fact, that you are "collecting the light" for 2-3 seconds. Try to open the apperture, set higher ISO or use flashlight. All this will increase the exposure allowing shorter times/faster shutter speeds.
If you are in full auto, move the selector to P, where you can set exposure and ISO, or to one of A,S,M regimes.
It sounds like you might have the two-second timer enabled. When you press the shutter button the mirror moves up. Then two seconds later the camera takes the picture.
This is a useful feature when shooting from a tripod and using shutter times from around 1 second to 1/100 second when the vibrations from the mirror movement can actually affect the photo. It's also useful if you want to press the shutter button yourself and then move into the frame before the picture is taken.
If you don't want or need to use the two-second timer then turn it off and the camera will take the image as soon as you press the shutter button all the way.