I have a problem with the sound of the low end keys on the keyboard. They don't sound loud even with the volume on 100%. Is this normal or the speakers are just weak? If I change the weighted key action to off the sound loud as the other keys. Also this happens only to grand piano, live grand and live warm. I have changed the eq settings but sill no change. From the headphones th sound fine and from synthesia too if I put a higher output volume. External speakers doesn't help. Is there any software to boost the sound? Thanks for your answers!