The Edifier M1250 USB-powered speakers are inexpensive and sound clean and coherent on voice and music, but don't expect any bass.
The Edifier M1250 USB-powered speaker system is compact and lightweight, featuring two separate speaker units for putting either side of your notebook's screen. The whole system (including cables) weighs nearly half a kilogram, and the left-hand speaker alone — the one that has no built-in amplifier or electronics — still comes in at 198 grams.
Rather than the common round speaker drivers, these ones feature drivers shaped more like rectangles with rounded ends. The speakers are specified at 90x50mm by the vague conventions pertaining to speaker drivers (you measure from the screw holes). The actual working area is about 15mm smaller in both directions.
That makes the speakers quite a bit bigger than what seems to be the norm in USB speakers. That could translate into better bass, all else being equal. But the plastic enclosures are fairly compact, and have no bass reflex ports, not even behind the removable grilles.
Edifier says that each amp has 0.6 watts of power on tap ("RMS", which is inappropriately used here).
The right-hand speaker has a push button hard-wired power switch (which guarantees no power draw when switched off) and a volume knob, along with a 3.5mm headphone socket.
Compact speakers make for easy carrying in one way, but lots of wires make for difficult carrying. You have two cables for connecting to the computer, plus one stretching between the two. I'd be reluctant to cart these speakers around for another reason: the clothe grilles aren't backed by a plastic grate. It's easy enough to push in the cloth and touch it through the cone of the speaker. And, indeed, somehow in transit, although the system looked to be factory packed, something had been pushing through the grille onto the left-hand speaker, deforming its rubber roll surround.
This made no apparent audible difference, and I did all the measurements with the right-hand speaker anyway, but it does warn of danger.
Connections were done in the usual way: green plug into headphone socket, USB into USB. Easy as.
The headphone socket simply bypasses the speaker system's electronics (aside from having an integrated switch to stop the speakers themselves from working). That's good in one way, because it means that you're getting the signal direct from the computer without it being potentially adulterated by the speakers' amps. But it's not so good in that the volume knob on the speaker doesn't work. You will need to use the computer's own volume control, however that works.
As for the speakers themselves, do not expect any noticeable bass. They sounded smooth and reasonably clean across the mid-band and, according to my measurements, were actually good to beyond 20,000 hertz. Their output increases gradually as you go down in frequency to reach a peak at 500 hertz, below which it starts falling away again. At 350 hertz it is back at the average of the higher frequencies, and there is no useful output below around 250 hertz.
A bigger speaker driver can be useful in various ways, but it needs help from its enclosure to do its work. Putting one in a small sealed enclosure like in this system is a lot like putting a spring at its back, resisting its motion. Indeed, another name for sealed loudspeaker enclosures is "Acoustic Suspension".
That frequency response graph matched closely with how the system actually sounded. Indeed, it sounded rather good on the classical guitar, with excellent bite and a nice bit of air around the instrument. Likewise, the podcast was good and clear and easily understood. But the rock stuff was rather light, due to a lack of significant bass content.
The Edifier M1250 USB-powered speakers are useful, low-cost units that miss out only due to the minimal bass.