There are plenty of decent portable speakers on the market but not many of them deliver loud sound. The Kube4 can. It is a WiFi enabled Bluetooth speaker that delivers up to 101dB sound. It has a frequency range of 50Hz to 20kHz. It lasts up to 40 hours on battery. The companion app lets you control your speakers, adjust the volume, and control up to 32 speakers.
This AirPlay 2.0 speaker can be synced with other units or play a different music in every room. It measures 18.7” x 11.3” x 8”, weighing 21lbs. This speaker is IPX5 rated.[where to find it]