Positive Grid Spark Live

There is no stereo separation between input 3 and 4 as marketing and manual let customer understand. Those two input channels (3 and 4) are just summed and outputted as mono sound. Even with earphones connected to Spark Live. Bluetooth connection plays in stereo and i guess also channels 1 and 2 mono input digital signals also, have not tested those troughout because do not need those. As mainly keyboardist i really would like to have stereo output from speaker itself as instruction manual and marketing let understand. And yes i have had it in horizontal position and i have tried to change 3 and 4 input modes to line input from default. Basically sound is ok speaker like this size.