Monitor Audio’s compact S150 Bluetooth loudspeaker (£150) is constructed from a mineral-filled polymer surrounding a cluster of four specialised drivers. These include a proprietary gold dome C-CAM tweeter flanked on angled baffles
by dual 3in C-CAM metal cone bass drivers and a rear-firing Auxiliary Bass Radiator (ABR). 

The C-CAM drivers are powered directly by Class D amplifiers, generating a claimed 40W, and are fed by a hi-res DAC. Frequency range is quoted at 80Hz-25kHz.

Other features include Bluetooth 4.0 with aptX, a USB for charging and a 3.5mm auxiliary input jack for connecting analogue devices. 

The S150 costs £150 and you can find out more details about it here.