The air flow could be maintained in the chanter and drone pipes through using the left hand to squeeze the bag during breathing periods. In the mouthpiece, there is a circular piece of leather attached to the bag that operates like a one way valve. The flap closes when the player stops blowing air flow and opens when blowing is ongoing. The cutting power is the capability of the guitar to be audible even when accompanying other instruments. This does not mean that a guitar must always be loud but it means fitting and filling dry areas instead. The variation of tone depends on the acoustic guitar s material and method of construction. The lid is the panel that protects the interior from dust while the lid stick is the wooden stick that holds the lid open when the instrument is being played. The music desk provides support for the score. The casing is the overall wooden body that covers the instrument and the keyboard consists of the keys which plucks the strings when pressed. It often does not need any accompanying instrument because the performer could play music on keys using the right hand and the accompaniment which has pre-set and bass chord buttons using the left hand. Air flow through reeds is generated by expansion and compression of the accordions bellows. A keyboard or a set of buttons handles which reeds will accept air flow which produces the tones. It is usually played by professionals in solo and to play in higher positions in the classical ensemble. On the other hand, the E flat tuba produces sound that is an octave higher than the contrabass tubas and is the customary orchestral tuba in the United Kingdom. The tenor tuba, also called euphonium, is pitched one octave above the contrabass tuba, B flat. Nowadays, clavichords are manufactured all over the world and have many buyers in the market. A few modern manufacturers are the British Peter Bavington, Swiss Thomas Steiner, American Charles Wolff, and Belgian Joris Potvlieghe. Playing the clavichord A key is pushed down to play a clavichord s note.