The reason for making this thread is not to compare quality so much as it is to compare which is more energy efficient. I would assume that USB speakers use less electricity (although I could be wrong as they may be just sucking the electricity from the PC instead of through a wall sockey), but the question is how much of a difference is there? If it is basically negligible then I see no reason to worry with getting USB ones, but if it is that big of a difference then I'll just go ahead & spend more on the USB ones.

Wow, hard question to answer.

Short answer: USB limits the power your speakers can have. Powerful speakers won't have enough with USB. BUT you can have some quality USB speakers (in terms of clarity) which don't go too loud).

Basically, it depends on how loud you want your speakers to be and how much bass and so on. Better speakers won't be USB, generally. And the power used depends on the volume used as well as the kind of music - so it's not like you have a fixed power use for a set of speakers.

fair enough... I looked this question up on the internet & couldn't find a damn thing... so thanks.

Ordinary USB ports can manage the output of 5 Volts. There are "specail"one that can do up to 12 Volts - they are marked with red colour around the port. I think the 12v ones are supported by newer motherboards. That is on the PC side. On the speaker side not that qualified but i think that most of the USB ones are just rubbish. I'd go for the ordinary speaker which I think would make a better money to quality and perhaps a longer life of the speakers. That is my opinion, though.
PS: Technically they are both electric powered :P

Since I use primarily laptops, and I am not happy with default laptop speakers (even on gaming laptops like ASUS G75VW), I've had for years certain Logitech speakers which give surprisingly good gaming audio for both their size, and the fact that they draw all their power from USB.

They also get the audio data digitally through the same USB cable (ie. you don't need to connect any separate audio cable to your computer's audio output), which also sounds cleaner than my other computer speakers which take the audio from the 3.5mm stereo jack plug. These speakers don't catch any interference from the air, like mobile phones, no extra humming sounds etc.

I've been extremely happy with these speakers all these years, they are just small enough to carry in the same bag as the laptop, ie, they are not too bulky. And as said, they sound quite good for their size, they got quite a lot of praise for that in reviews back in the day, and that's why I chose them in the first place (due to very favourable reviews).

The problem is, I don't see similar USB-only speakers of the same size being sold anymore. What happened? Almost all multimedia speakers, even those which draw power from USB, seem to require to be connected to the 3.5mm audio port nowadays. Some I see are just some very small/thin "laptop speakers" which are secured on the laptop screen, and they sound quite crappy in comparison. I don't want those.

I'd love to buy similar in the future, in case these ever break down. The problem also is, I have no idea what the model or make these speakers are. :) There's just a Logitech logo, I can't really see any other clear marking anywhere. I hope Logitech or someone else still makes similar USB only (laptop) speakers. These are so good that I've occasionally used them also with my desktop PC, now that its multimedia speakers died for good.

Found it! Little googling helped, the Logitech USB speakers I love so much are Logitech V20. I think I bought them back in 2005 or 2006, and they've been in active use ever since. Here are two (old) reviews:

http://www.everythingusb.com/logitech_v20_laptop_speakers.html

http://www.cnet.com.au/logitech-v20-notebook-speakers-240091562.htm

I have no idea if Logitech is making these anymore, at least I didn't find them in their homepage. Trying to find the next best thing in portable USB-audio speakers...

An EE can correct me if my thinking is screwed up, but here goes:

For two otherwise-equal speakers systems, with the only difference being the source of power, I suspect USB is more power efficient. But it has nothing to do with the speakers themselves. Instead, I posit that the difference comes from creating the power those speakers will use. Your computer is already creating the power to run USB ports, through its efficient and well-regulated power supply. Speakers powered from the wall will use some cheap-o wall-wart that will be sucking power all the time while plugged in, and are probably not nearly as tightly regulated or efficient as your PC PSU.

Get into bigger speaker setups and you likely won't have much choice, since they'll require more juice than USB can provide. However, at that size and price you may be getting a better DC Power supply compared to the typical wall-wart.

But, that's kind of an educated guess. To get a real-world comparison, the best way I can think of (at the consumer level) is to experiment with something like a Kill-A-Watt load meter to measure the combined draw between both setups.