Change is Good
Headphoneus Supremus
tbh. thx00 hd650 hd600 400i k7xx are headphone i considered in the same league. really comes down to preference at the end. i keep multiple headphone because i swap around them alot depending on my mood.
The K7XX is not in the same league as the X00 or 400i. It may be one of my favorite headphones of all time, but there is some noticeable grain there which makes it less resolving.
I ended up selling the K7XX and rebuying the 400i so I can have an open headphone that matched/bettered the X00's sound quality. The K7XX is good for the price, but slightly inferior.