A spectrogram is no longer needed, a solution was added in the new update.
Press the U Key and it'll bring up a program which translates the Shadow Figure's noise into words when you use the Hollow Aura on them.
Viewing post in Let's Go Baby: Suffocation comments
No I don't unfortunately as I've been trying to get in there. I thought I had to ram my body into it by sprinting but that didn't work and I tried every aura but to no avail.
It doesn't help that none of the Shadow People don't give any helpful advice on how to progress and the minimum number of blocks I was able to get was two.
I searched every nook and cranny I could find only to find nothing that would help me to advance, the only way I could think of to progress was to reach the ham once Daddy takes over the world only to find there was no way to get to it which includes being unable to break the glass.
There might be a way to get past Daddy and enter his room after he takes over but so far all my attempts result in Daddy speaking to me and blowing off my head which ends in me being set back to the spawning area.
I also thought there was a way to talk to the Giant Baby in the aquarium level but every aura I tried had no effect, so I'm sorry to say that I'm just as stomped as you and everyone else here.
I wish there was a new game option so I could go back and visit the areas from the original game.