[MindsMirror]

There is this really strange noise that I hear at the beginning of "what is and what should never be" when I listen to it with headphones. Actually, I wouldn't even call it a noise necessarily, more like an odd effect. I was wondering if anyone else hears this. Right at 3 seconds, there is a sound (or something) that makes it feel sort of like my ear pops as if changing altitude, or like a quick burst of pressure on my eardrum.
 
It is only in one of the channels, but I have two different copies of the album and the channels are reversed in one of them and I don't know which is correct, so I don't know which channel it should be in for you if you are listening to your own CD. In this video it is on the right:
 

 
I only hear this effect in headphones. I thought it could be a low frequency pop, but I don't hear anything like that on my speakers. I looked at the spectrogram in audacity and didn't see anything I thought could be it. I've never experienced anything like this on any other songs. I wouldn't even think it was possible for my headphones to produce such an effect, they are not particularly bass heavy. My headphones are Grado SR125e. I also hear it on my Corsair Vengeance headset, although not as pronounced (they are very light on bass).
 
I'm curious, does anyone else hear anything like what I described? What exactly is it?

 

[GrindingThud]

Sounds like a tape dropout from the master....you may find enlightenment here:
http://forums.stevehoffman.tv/threads/led-zeppelin-2014-remasters-i-iii-cd-format.358818/

 

[MindsMirror]

Sounds like a tape dropout from the master....you may find enlightenment here:
http://forums.stevehoffman.tv/threads/led-zeppelin-2014-remasters-i-iii-cd-format.358818/

 


Looks like you're right.
 

 
It seems I wasn't looking hard enough before. I changed the FFT size and found that blank spot on the right channel at 0:03.25.
 
I wouldn't have expected a dropout to cause the effect that I described. I guess it's like an impulse except opposite. Instead of energy across the whole spectrum, it is a sudden lack of energy, so maybe it does make some sense.