I've owned a pair of Grados for about ten years. I've grown very fond of them and in particular their most celebrated qualities (detail, transparency, etc.). I won't spend much more time writing about why I love these headphones as others have covered this extensively. What I'm going to focus on is how they differ from the Grado GW100x.
The first thing you notice is that there is no cord. More accurately, the cord is optional as this set is equipped with Bluetooth. I've avoided Bluetooth audio for years for a number of reasons (primarily poor sound quality and dead batteries. The new Grados solve the second problem by including a removable headphone cable which can be used when Bluetooth is not available (or the batteries are dead), but what about the first?
So far I've used these wirelessly with two devices: a System76 laptop and an iPhone 13 Mini. The music I've listened to consists of compact disc sources encoded in lossless FLAC. The software used for playback is Melody on Linux and Doppler on iOS.
On Linux the headphones show-up as two different Bluetooth devices: "Headset - Grado GW100w" and "Handsfree - Grado GW100w". The less said about the latter the better (as it is very low-quality as well as monophonic) but it is the only way I've found to enable the microphone that is included in the headphones. I won't complain about this too much as I don't think most people will be buying these for their excellence at taking telephone calls, but I do find it inconvenient to have to switch between devices when moving from listening to music to taking a Zoom call.
The "Headset" device presents several additional options to choose from. I'm no expert on Bluetooth audio tech but based on what I've observed so far these options specify the audio codec that will be used to encode the music sent to the headphones. The default option is "High Fidelity Playback (A2DP Sink, codec aptXHD)", and I have to say that it sounds exponentially better than any other Bluetooth audio I've auditioned. As I've mentioned I've avoided Bluetooth for listening to music because I've found the quality to be grating and the complexity unnecessary (why all this tech when a cord sounds better?) but I'm impressed by this. After a few hours of listening I'm not experiencing the fatigue I associate with other Bluetooth devices so maybe it's evolved enough for me to enjoy it?
I'd like to know more about the differences between these options. Flipping between them for a few minutes I didn't notice any obvious advantages/disadvantages but I'm sure there are trade-offs. Something to investigate in the future.
The headphones provide three physical control buttons (power/play/pause, volume up/next track and volume down/previous track) which will control the volume on my Linux laptop but don't do much else. This may be a limitation of the Linux distro I'm using or the software I'm using for playback, so I won't fault Grado for this but it is a bummer.
On iOS I didn't notice multiple Bluetooth devices/options. I'm not sure if that's because I didn't look very hard, or if iOS handles this more automatically, but I've also not yet used them to take a call on iOS so I don't know if the microphone is working. Quality-wise the sound is excellent as well, and the hardware controls on the headphones are much more useful (play/pause works, as does skipping tracks forward and backward using a long press on the volume controls).
At first I thought that the battery state information was missing as I've used other Bluetooth headphones which indicated how much charge remains in their battery on iOS, but I didn't see this when using the Grados. After some poking-around I noticed that this is visible on one of the iOS "dashboard" screens, it's just not displayed in the ever-present status bar (possibly due to the smaller screen size of the iPhone mini?).
One last thing I'll note about the Bluetooth is that the range is excellent. I was able to listen uninterrupted while walking to the other end of the house (with several walls in-between the headphones and my laptop). This was a big surprise compared to other Bluetooth audio devices I've used which seem to drop-off after about 15 feet or when you loose line-of sight with the source.
So aside from the wireless technology what else is different? To my ears the GW100x exhibit the sonic characteristics I love about my other Grado headphones. The sound is clear, transparent and incredibly detailed. I will add that there seems to be a little more "punch" as well, perhaps because there is some amount of integrated amplification (I usually listen to my corded Grados directly connected to the headphone jack without a headphone amplifier). The GW100x has all the openness and the spacial qualities that for me put Grado in a category of its own. To this end, I think they deserve the Grado name, and I don't think anyone looking for that sound will be disappointed by these headphones.
Comfort-wise they are more comfortable than my SR125's were with the original cushions but not quite as comfortable as they are with the replacements. The GW100x are heavier, and this is noticeable over a few hours. Not as bad as other headphones I've worn but here the advantage goes to the 125s. The padding on the strap of the GW100x is thicker, and more comfortable across my shaved head but I'm not sure how much difference it would make to someone with more insulation up top.;
To wrap it up I don't think there's anything about the GW100x that would make me replace a pair of corded Grados in terms of sound quality, comfort or other aspects of listening to music; in these areas I think the GW100x meets but does not exceed a traditional pair of wired Grados. But if you want that sonic experience with the convenience of going cordless, and perhaps ditching your dedicated "telephone headset", the GW100x lets you do that without compromise.
