This saber is forged of a lustrous white adamantine alloy, making it incredibly resilient to damage. The blade is unusual, with a bar running parallel to the back of the blade with about a quarter inch gap between it and the blade ending a inch or so behind the tip of the blade. The bar and blade both merge at the ricasso. The gold full basket hilt is unusually padded on the inside. The scabbard that comes with it is wide enough for the blade, leaving the bar outside.
You gain a +1 bonus to attack and damage rolls made with this magic weapon.
Vibration. When an action is taken to strike it against a solid object, this weapon starts to vibrate and hum. The weapon deals an additional 2d6 force damage, as the vibration rips and tears and shakes apart the target. It also deals double (4d6) damage to constructs and inanimate objects. Hitting a sufficiently hard target with an attack is enough to cause the sword to begin to vibrate. Sheathing the weapon in its scabbard will end the vibration as will using the thunderwave ability.
Someone who trains to do so, can draw Sono in such a way to activate the vibration ability.
Thunderwave. As long as the vibration ability is active, the wielder can take an action to end it by touching the tip of the bar to the blade. This releases the vibration in a blast of sonic energy, releases as a thunderwave spell cast with 3th level spell slot, with a DC of 14. The vibration ability is ended, though it can be reactivated as normal.
Flaw. When vibration is active, there is a 1 in 10 chance that when the weapon deals damage, the bar and blade touch, causing the thunderwave ability to trigger, ending the vibration ability as normal.
When ever the thunderwave ability is activated, the wielder is always affected, and has disadvantage on the save, with the wielder in the center of the effect.
If the blade is sheathed while vibration is still active, the weapon unleashes the thunderwave effect, with the wielder in the center of the effect.