When the engine spool up (in start phase, when starter is active) and pass approx. 10-12 % N1, a load bass sound is observed. Does this sound orign from the engine or from resonans in a/c body?
Hello,
are you sure about these N1 values ? The loud sound you are talking about makes me think to when we put the start levers on idle detent and hence we open the fuel shutoff valves. At that stage the fuel is lead into the combustion chamber and is ignited. That is what actually comes into my mind.