Some loud Bluetooth speakers are the Jawbone Big Jambox, the Bose SoundLink Mini II and the JBL Flip 3. Most Bluetooth speakers have rechargeable batteries for portability.
The Jawbone Big Jambox is three times bigger than the original one measuring 3.6 inches by 10 inches by 3.1 inches and weighing at about 2.7 pounds. Its has a box-like design with rubberized top sides and wraparound metal grill. At the bottom, it's equipped with eight rubber soles to reduce movement caused by heavy bass and sound that can fill a medium-size room. It has a 30 foot transmission range and is A2DP compatible. It takes two and a half hours to charge and has a 15-hour battery life.
The Bose SoundLink Mini II weighs only 0.5 pounds with a box-like design and an inbuilt microphone for speakerphone capabilities. It comes with a 10-hour battery life on full charge, and it's charged via a standard USB cable. It can pair with two devices and produces enough sound to fill small rooms like a dorm room, kitchen or bedroom.
The JBL Flip 3 weighs in at less than a pound. It can stand vertically or horizontally and is water resistant with a flap that covers the USB and audio ports. It has a noise and echo cancelling speakerphone and has a range of about 33 feet. It produces 8 watts of sound and has a listening distance of up to 12 feet.