JBL Studio 580 vs KEF Q950: which should you buy?

The KEF Q950 is the better speaker of this pair, ahead on midrange clarity, treble detail, bass and design by clear margins and narrowly ahead on overall sound quality. Value for money is the one column that goes the other way, and it goes there clearly.

Buy the JBL Studio 580 if the budget matters more to you than the last few percent of refinement. It is the value winner here by a clear margin, and that gap widens further if you catch it on a deal rather than paying full retail. I would put it in a movie-first system: the stage is transparent, instruments sit in the room rather than behind a curtain, and the tweeter throws out a lot of detail. Two things are worth knowing before you commit. The treble runs forward and can tip into sharp on bright material, and the low end is the fussy part, wanting sensible placement, the supplied baffles or a little room treatment before it settles. The plastic feet screwed into the MDF enclosure are the weakest part of the build.

Choose the KEF Q950 if the system is being built around listening rather than around a price ceiling. The condition attached is power: the amplifier range runs from 15 to 200 W, and it wants the upper end of that, cleanly delivered, before it fully opens up. Bass-focused listeners may still want a subwoofer underneath it. In return it is the more forgiving of the two about where it sits, which counts for a lot in an open-plan or awkwardly shaped room, and it holds together without distortion when you push the volume. The finish is where it disappoints: the vinyl wood look and the loose fit of the plastic rings around the speakers undersell it, and that is part of why it loses the value argument.