[nameBrandon]

I just received my Sennheiser PXC-450's last night. I'm going back and forth between these and the QC15's (sorry, I'm not a huge Bose fan either) and have some strange things happening.. I'm hoping there's another owner or two out there who can confirm this is normal (or not).
 
When in NC mode, when I come across an external loud, low frequency sound, I get a 'flutter' or almost like feedback.. like the wave created to cancel out that low-frequency sound is out of phase with the actual sound.. This usually happens when accompanied by vibrations, such as my train commute or when passing construction machine (bulldozers). I also notice this to a lesser degree when turning my head every now and then with the headphones on.. To be clear, I've never tried to see if this happens when listening to music, there's always been no input to the headphones when this happens.
 
I've read one or two other people mention this in their reviews, this gentleman probably describes it more accurately.
 
 

" but I had trouble with a tendency for the cans to start oscillating at very low frequencies. Some part of the noise canceling feedback loop is interacting with the acoustics of the headphones and providing positive feedback at about 30Hz. This phenomenon got worse when I put my head next to a wall, which I assume is reflecting some of the sound back toward the headphones and making the feedback worse. I couldn't make measurements of these headphones because of this low frequency problem when I put them in my measurement chamber. I suppose it's possible there is something wrong with this particular pair, but I have heard these at trade shows a number of times and always walked away unimpressed."

 
I'm not sure I can accurately describe this in words, so I'm linking to a youtube video of a lightsaber (yes.. seriously.. ).. If you listen to the first 2 seconds of the video, listen for the lower frequency 'flutter'.. that's kind of what I hear, but the frequency of the flutter is usually lower.. The guy I quoted mentioned ~30Hz, and after listening to what 30Hz sounds like, I'd say that's pretty accurate.
 
Light Saber Video - http://www.youtube.com/watch?v=sNwQqqOJzMM
 
This is just playing havoc with my eardrums, kind of like rapid pressure changes.. Can anyone with this set confirm this is normal or that they've had this happen? I love so much about these headphones and would love to keep them over the QC15's, but I can't deal with this low frequency oscillation all the time.
 
I'm hoping it's a defective pair, but since this has been mentioned at least 3 other times in (the hundreds of) other reviews I've read, I'm scared this just might be how they are.
 
Thanks!

 

[nameBrandon]

any other owners out there? Unfortunately they're boxed up and ready to go back.. Just curious if other owners have experienced anything like that, and if I should give a different pair a try?
 
Heading to a local high-end store tomorrow to demo some headphones to see if maybe noise isolating might be an option.. Love the Bose NC, but the sound is so far away from what I loved about the Sennheisers.. If I can't find an isolating set that's got a good sound I guess I'll just settle for the QC 15.

 

[joshtheonlyone1]

Hi Brandon,
 
I just wanted to say I experienced the same exact thing a couple years back. Then found your review online and returned them. I went for the AKG500 instead, very satisfied with my choice
 
Cheers,
Josh