BTW, I don't know how I missed these headphones. Late last year I started experimenting with Wireless noise canceling headphones. And I bought a few of them to sample, Bose QC35, Sennheiser HD4.50BTNC, Sennieher PCX550, Sony MDR1000x, and Bower & Wilkins PX. I was disappointed with most of them especially the Bose QC35 which sounded the worse. I wound up sticking with the Bowers & Wilkins PX, which is the most serious you can get to audiophile with bluetooth. The sounds is the most neutral and it supports AptX-HD. But somehow I never ran across the Denon AH -GC20. It was only recently by accident when I was looking in to headphones with AptX LL so I can watch TV with and I stumble across them. They once retailed for $400 but Amazon has them for $170.
I really enjoy the comfort which is comparable with the Bose, and built quality is comparable with the Bowers & Wilkins. Sturdy,no creaking, or wiggly buttons making noises every time you move your head.
The sound is not neutral, the sound signature is warm and there is a bass emphasis in the 50 hz-60 hz region. But thankfully the mid section is not effected much,with only a slight v shape in sound while still being comparable with neutral headphones. The treble is present but with no emphasis, Denon is going for a more pleasant relaxing sound, without feeling like something is lacking on top.
And then comes the weird part. The noise canceling. With all the headphones I mentioned, the sound quality diminishes. But with the Denon, the the sound actually improves a little. The upper mids push up a bit. and then there sounds some kind of stereo enhancer kicks in. This is the opposite of the the other headphones like the Bose where the treble drops and the stereo get narrower. The Noise canceling itself is comparable with the Bose and Sony. The world around you is muted to a good degree and if you talk, its sounds like you can hear the sound of your voice coming from with in your head rather than in the atmosphere, similar to being in an anechoic chamber. In fact as I'm typing this, I can not hear the keys being pressed on my keyboard.
If there are bad things to say its that, the earcups could be just slightly larger and deeper for my ears as the upper tip of my ear does touch the inner driver. And after long listing sessions they start to feel a little uncomfortable and I need to adjust them to a different angle. And it doesn't appear as if the earpads are replaceable. So I worry what happens if and when they wear out. If anyone has owned these since 2015 let me know how they hold up.
While I do enjoy the bass, I have to admit that the bass is a bit one note. It's lack the texture, resolution and quality of true audiophile headphones, and could be summed up in just one word. "boomy".
And the last thing is the Bluetooth paring. The pairing is slow, and can it can take 30-55 seconds sometimes. There is also no voice of what device you are connected too, just a low beep indicating that your are connected to something. While you can pair up to 2 active devices simultaneously, the manual isn't clear on how many paired devices it can store. before it overwrites previous parings. Its seemed like when I paired more than 3, it overwrote the first one, because I couldn't connect anymore, and I had to repair.