Devotec's Solar Sound 2 is probably the best portable speaker for travel currently. There are some issues with the Solar Sound 2 but we will get to those later on. The Solar Sound 2 can both be used over Bluetooth or 3.5mm audio cable. The best thing about the Solar Sound 2 speaker is the fact that it's powered by the sun! Yes it can be charged via USB but who wants to do that when you have a big solar panel built onto the top. I've used the Solar Sound 2 for days without having to charge it over USB, the sunlight has kept this ting going and going. I have yet to actually charge it myself, and this I really like. So we covered the biggest function about this portable speaker which is the fact that it can be powered by the sun.
Now onto the sound quality -- The Solar Sound 2 is pretty compact and portable with two speakers at each side that provide stereo sound at very high volumes. I was able to get a very loud sound level in a big living room, so sound level isn't the issue really. The sound quality is much better than what your iPhone or other mobile phone can produce. The Solar Sound 2 has a nice clear sound at normal sound levels. However, once you go beyond the 80% mark, you will start to get sound distortion effect on most songs. The bass quality isn't bad but nothing too exciting, definitely not punchy. I would say Devotec needs to improve the sound quality a bit here. The sound quality improves if you directly connect your audio source with the supplied 3.5mm audio cable but it isn't something really noticeable. The Solar Sound 2 has touch sensitive control buttons that work very well but you will mostly find yourself not using them.
The build quality is very solid and doesn't feel cheap. If you want to use your Solar Sound 2 over Bluetooth with anything other than an iPhone or a different mobile phone, you will not be able to as it will not be compatible. You can directly plug any audio device right into the Solar Sound 2 without any issue though. The Solar Sound 2 could definitely benefit those who need a mobile speaker that does not need any batteries or the hassle re-charge times. With the Solar Sound 2 you will get a USB wall charge with a USB and 3.5mm audio cables as well as a travel case. Price $99.99.
The Solar Sound 2 will support iPad and iPod Touch bluetooth profiles starting next month. Currently the Solar Sound 2 only supports iPhone and most other mobile phone HFP bluetooth profiles.