John F Yungman

54232414, Jun 13, 1995

Oct 5, 1992

7/957883

Henry A. Scarton - Troy NY
Warren C. Kennedy - Feura Bush NY
John F. Yungman - Delmar NY
Paul N-J. Liang - East Brunswick NJ

Rensselaer Polytechnic Institute - Troy NY

G10G 702
G01N 348

84454

A method for measuring dynamic hardness of elastic materials is applied particularly to determining the state of tonal quality for a piano hammer. The method includes selecting a piano hammer of predetermined type from a set of piano hammers, causing the selected piano hammer to strike against an impact surface having the form of a piano string or string grouping appropriate to a piano hammer of the predetermined type, measuring one or more elements of force and motion of the piano hammer striking the impact surface, e. g. force, determining, e. g. , the cut-off frequency of the power spectrum for the selected piano hammer striking upon the impact surface, and comparing the determined cut-off frequency of the power spectrum for the selected piano hammer against a predetermined range of cut-off frequencies of power spectrum acceptable for piano hammer of the predetermined type. An apparatus for testing is also described.

55378625, Jul 23, 1996

Nov 1, 1994

8/333057

Henry A. Scarton - Troy NY
Warren C. Kennedy - Feura Bush NY
John F. Yungman - Delmar NY
Paul N-J. Liang - East Brunswick NJ

Rensselaer Polytechnic Institute - Troy NY

G01N 342
G01N 300

73 82

A method for measuring dynamic hardness of elastic materials is applied particularly to determining the state of tonal quality for a piano hammer. The method includes selecting a piano hammer of predetermined type from a set of piano hammers, causing the selected piano hammer to strike against an impact surface having the form of a piano string or string grouping appropriate to a piano hammer of the predetermined type, measuring one or more elements of force and motion of the piano hammer striking the impact surface, e. g. force, determining, e. g. , the cut-off frequency of the power spectrum for the selected piano hammer striking upon the impact surface, and comparing the determined cut-off frequency of the power spectrum for the selected piano hammer against a predetermined range of cut-off frequencies of power spectrum acceptable for piano hammer of the predetermined type. An apparatus for testing is also described.

20140363035, Dec 11, 2014

Jun 5, 2013

13/910154

- Stamford CT, US
Brian Sterling - Farmington Hills MI, US
John Yungman - Northville MI, US

H04R 9/04
H04R 31/00

381182, 29594

A coaxial loudspeaker includes a permanent magnet positioned between a generally coaxially aligned first transducer having an associated permanent magnet and second transducer having an associated permanent magnet. In one embodiment, a magnetic cylinder is positioned between a woofer and a tweeter of a coaxial multi-way loudspeaker. An optional support structure, such as a plastic cylinder, may encompass the permanent magnet to enhance structural characteristics of the assembly. The woofer may include an external ceramic magnet extending around a center pole of the woofer.