Headphones

I tried the dt 1990 and HD660 but ended up with Grado Hemps for the win. 

I just got Sundaras and love them! I would also look at 6xx and beyerdynamic dt 1990

I have about a dozen headphones, including top of the line cans like LCD-4. The Sennheiser HD-6XX are the ones I probably use the most. They are not the "best" in any way, except maybe comfort (especially with upgraded pads). What I like about them is that they are super comfortable and really easy to listen to. Nothing draws attention to itself.

The AKG 7XX are really good also, but I like the Senns a lot more.

No experience with the 501s, so I can't comment on how they compare. I had the HD600 and sold those. I strongly prefer the HD-6XX.

I would like to recommend to you the naenka tws headset I am using now. It has Qualcomm 3040 chip and Bluetooth 5.0 technology. It can be used for 7 hours on a single charge and the total battery life of the charging compartment exceeds 28 hours. It can meet the music needs of travel and business trips. .

Had 501's, sold them. Had 701's, sold them. Own HD600's. Not for sale

https://www.head-fi.org

The sennheiser 600s are a reference for many.

listen to Audeze.  They knocked my socks off.  "LCD-2" for affordable high end.  "Sine" for sealed travel or work headphones.  I bought the Sine to use at my office desk and on airplanes.  I will buy the LCD-2 next...