Patent ID: 7335832

Claim:
In a blank adapted to be coiled about a longitudinal axis to form an acoustic impedance-inducing device for placement in the air column of a wind instrument, said blank including at least first and second parallel bands separated by a first web, each extending transversely to the longitudinal axis, said first band being of a first predetermined length, said second band being of approximately twice said predetermined length, and said first web being of approximately the predetermined length and formed of a series of diagonal spacer strips in alternating opposed diagonal arrangement, the improvement comprising: a first side edge of the first web is defined by a first diagonal end spacer strip; a second side edge of the first web is defined by a second diagonal end spacer strip; and said first and second diagonal end spacer strips are oriented with respect to each other as opposed diagonals such that when the blank is coiled, bringing the first and second side edges of the first web into juxtaposition, the first and second end spacer strips of the first web define an open first triangle between the first and second end spacer strips and expose a first triangle base lying along an edge of one of said first and second bands.