Useful on paper. Bought after researching the market for similar items, it has great features and feels sturdy. However, the sound is tremendously poor, heavy distortion and "limit" indication before 50% of gain on the channels and master. Guess this can be useful for classic music or jazz, acoustic appliances. On stage, for keyboards, together with guitar-amps and similar this product, how good it might seem, do not deliver sufficient sound level or quality, unfortunately.