Song sound is terrible when trying on Itunes, any suggestions?

Question

When i try a song before buying it is very scratchy and of poor quality. No sense buying if i can't distinguish.

Answer 1

Try resetting the SMC (see: http://support.apple.com/kb/ht3964 this link has all the steps and options)
Press Command + Option + Escape to force quit any application that is not responding.
Put your Mac to sleep by choosing the Apple () menu from the upper-left menu bar and then choosing Sleep.  Wake the computer after it has gone to sleep.
Restart your Mac by by choosing the Apple () menu from the upper-left menu bar and then choosing Restart.
Resetting the System Management Controller (SMC)
Resetting the SMC on Mac portables with a battery you can removeNote: Learn about removing the battery on MacBook and MacBook Pro.
Shut down the computer.
Disconnect the MagSafe power adapter from the computer, if it's connected.
Remove the battery.
Press and hold the power button for 5 seconds.
Release the power button.
Reconnect the battery and MagSafe power adapter.
Press the power button to turn on the computer.
Resetting the SMC on portables with a battery you should not remove on your own
Note: Portable computers that have a battery you should not remove on your own include MacBook Pro (Early 2009) and later, all models of MacBook Air, and MacBook (Late 2009).
Shut down the computer.
Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
Release all the keys and the power button at the same time.
Press the power button to turn on the computer. 
    Note: The LED on the MagSafe power adapter may change states or temporarily turn off when you reset the SMC.