Resmed Humidifier H4i makes Darth Vader-like sound

I actually asked this question before but there is still a problem with my humidifier, so I am going to ask a little differently: is it normal for a humidifier to make this type of sound (like "breathing-in" sound whenever you inhale)? I know I might sound dumb here, but I figure maybe the reason I start noticing the sound now is because 1)now I put the CPAP on the night stand by my bed instead of on the floor 2) I had never listened to the humidifier directly aside from the one time I did, and before I just thought that it was the sound of my mask. However, I also notice that the leak rate has been pretty high (0.4 L/s) but that could also be from mouth-leaking. I've replaced the cover lid and the water chamber, but the sound still persists. If anyone has an idea what's going on, I'd really appreciate it. It has been quite painful not using a humidifier

If you put the machine directly onto the hard surface, the furniture may be performing as a sound box.
Ever wonder why an acoustic guitar has a big hollow wood shell? Sound amplification.
Many folks put a pad under the machine to stop that.

Also make sure you don't over fill it. In fact try it half filled.
And put it lower then your head.