There will be some changes in the upgrade line of K450, but it is really unnecessary on this low-grade K450 (what grade of horse is equipped with what grade of saddle). 1, if you want to improve the sound quality, it is obviously recommended to buy 2000 to 3000 large headphones or earplugs (there is no doubt that the sound quality of big ears at the same price is definitely better than earplugs). 2. If the original cable is damaged, it is recommended to buy one above 30 yuan from Taobao. The original distribution line of headphones of any grade is the most suitable for it. Manufacturers will naturally adapt suitable wires according to their grades, and the wiring will also change, but whether this change is "upgraded" needs to be questioned. If you want to improve the sound quality of portable equipment, you can only upgrade it from "sound source file, front end, earphone". The earphone cable is secondary, you don't need to consider it, because the manufacturer has already adapted the appropriate cable for you when buying headphones.