Tiida 2008 Low Whistle noising not from transmission

[ZuZ]

recently my car started giving this low but hig pitched whistle when ever the engine revs up a little.. at first i thought it was from the transmission but i tested it on P and on N even on D and R .. the same result..next to tried to find a way to reproduce the sound.,.. and discovered that whenever i tap a little on the gas pedal, and as the engine revs up a bit,,, the whistling noise appears for a sec and then disappears,, and as soon as i remove my foot from the gas pedal and as the engine revs down.. at about the same rpm the whistle appears again..

now the sound isnt like a humming or clunking sound.. its more like a low whistle, i cant hear it when am driving on a highway but can hear it when cruising around..

can anyone please tell me his opinion, as its a long drive to the dealer!

[shades14]

same happens to mi.. dont know what is call. but something to with speaker picking up the soundwave or sumthing..

[ZuZ]

bump...... anyone!