During the Chinese Spring Festival, my dad gave me an Edifier M120 Bluetooth speaker. This speaker is not one of these high-end models featuring dedicated bass speakers or professional Bluetooth audio codecs such as aptX and LDAC; it's just a unit with two ordinary speakers. With that said, I doubt I can hear any difference with those advanced codecs on a portable speaker anyway. But when I played some music with my phone connected to it, I realized that it does have some bass output. Speaking of bass, I'm impressed by a JBL Charge 4 speaker bought by one of my classmates. As a portable speaker that costs $150, it has a dedicated bass unit with astonishing power. Then I began to think that, although my speaker costs a mere $20 (converted from CNY),...