Let's face it, portable multimedia playback devices have been replaced in the last 10 years by smartphones, these all-in-one devices that can do "anything". Meanwhile, the companies that used to produce music players have refocused, but Sony remains one of the few companies keeps the flag standing. Recently, they introduced the Walkman range called "Signature", dedicated especially to audiophiles. The newest models, NW-WM1ZM2 and NW-WM1AM2, reach prices of up to $4,200. As you can see in these images, the top Sony Walkman is gold plated . These new Walkman MP3 players are so exclusive that they don't even have clear brand names. Sony is presenting them with the model number, something that's almost impossible to remember. These two models replace the offer with two similar devices from my old generation,…