Out of curiosity how does noise canceling works when on the device?

I assumed it was only possible when on the headset as it needed to be measured and cancelled based on the direction of the sound.

I'm failing how a device in your pocket can cancel any ambiant noise

If I’m reading the specs right it looks like their headphones are required. I’m guessing mic’s are on each side and offloaded to the player? Either way, I wouldn’t want to be forced to use their headphones.

The best noise canceling headphones I have owned and am using now are wired and can be used with anything that has an audio jack: Bose QC25 (active, found refurbished) and Shure SE215 (passive with original black foam sleeves).

No reason you can't have noise cancelling with wired earphones to the Sansa, Bose QC20s etc.

I assume also there are jack-to-bluetooth adapters for wireless.

QC20 are not an option for me because of the extra device that is built into the cord close to where you plug it into the mp3-player. It makes handling of the whole system cumbersome.

I guess the noise-cancelling has to be built into the mp3-player to avoid this. I have not seen elegant in-ear headphones with built-in noise-cancelling yet.

No need to have noise cancelling as part of the mp3 player.

Bose QC35 are wireless but also come with a optional 2.5mm to 3.5mm jack cord.

I imgaine that there's lots of alternatives on the market too.