I recently came across someone who owns a shofar which has a mouthpiece attachment that circumvents the need to vibrate your lips.
A typical shofar requires a bit of skill and practice in that you need to vibrate your lips to create the sound. This shofar was created with a type of metallic mouthpiece which creates the vibration for the sound. You simply blow air straight in (like a whistle) rather than having to pucker your lips and create vibration.
Does such a change invalidate its use for religious purposes or is this actually valid but just an uncommon alteration?