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While loudspeakers are the most important component, the room is vital to consider (unless your using headphones/earbuds

). Avoid small, squarish, weirdly shaped, poorly insulated, and non-dedicated rooms. Take your time when auditioning loudspeakers. Learn what musical genres and aural attributes you like. Limit yourself to 3 or 4 per day to limit listener fatigue. Bring a wide variety of your favorite music including poorly recorded selections to make sure you're not limiting your listening to only well recorded material. Take notes to force yourself to critically listen and avoid fleeting aural memory. Make an adventure out of it.
Amps simply serve the loudspeakers. Higher efficiency loudspeakers (90-95 dB/w/m) are best, not so high that they reveal system noise but not so low that they aren't dynamic/take hundreds of watts to "wake up". Amps should be big enough to provide a commanding grip on the loudspeakers for improved resolution, typically that means 40-100 watts for higher efficiency and a medium sized room. Source type(s) is up to you. Vinyl provides more of a hobbyist feel but limited content availability. Streaming once setup provide convenience and access to tons of content.