A dual probe and wedge assembly comprising a dual probe assembly attached to a wedge assembly, wherein the dual probe and wedge assembly has a central plane of symmetry, and, wherein the dual probe assembly comprises: a probe housing; at least one left pivotable joint member (20a, 22a); a left transducer pivotably attached to the probe housing by the at least one left pivotable joint member (20a, 22a), the left transducer having a left transducer contact surface; at least one right pivotable joint member (20b, 22b); and, a right transducer pivotably attached to the probe housing by the at least one right pivotable joint member (20b, 22b), the right transducer having a right transducer contact surface; and, wherein the left transducer is free to rotate about a left rotation axis and the right transducer is free to rotate about a right rotation axis; and, wherein the wedge assembly comprises: a left wedge having a left wedge contact surface inclined at a left roof angle to a perpendicular plane, wherein the perpendicular plane is perpendicular to the central plane of symmetry; and, a right wedge having a right wedge contact surface inclined at a right roof angle to the perpendicular plane; and, wherein the left transducer contact surface is in contact with the left wedge contact surface inclined at the left roof angle, and the right transducer contact surface is in contact with the right wedge contact surface inclined at the right roof angle. wherein the dual probe and wedge assembly has a central plane of symmetry, and, wherein the dual probe assembly comprises: a probe housing; at least one left pivotable joint member (20a, 22a); a left transducer pivotably attached to the probe housing by the at least one left pivotable joint member (20a, 22a), the left transducer having a left transducer contact surface; at least one right pivotable joint member (20b, 22b); and, a right transducer pivotably attached to the probe housing by the at least one right pivotable joint member (20b, 22b), the right transducer having a right transducer contact surface; and, wherein the left transducer is free to rotate about a left rotation axis and the right transducer is free to rotate about a right rotation axis; and, wherein the wedge assembly comprises: a left wedge having a left wedge contact surface inclined at a left roof angle to a perpendicular plane, wherein the perpendicular plane is perpendicular to the central plane of symmetry; and, a right wedge having a right wedge contact surface inclined at a right roof angle to the perpendicular plane; and, wherein the left transducer contact surface is in contact with the left wedge contact surface inclined at the left roof angle, and the right transducer contact surface is in contact with the right wedge contact surface inclined at the right roof angle. a probe housing; at least one left pivotable joint member (20a, 22a); a left transducer pivotably attached to the probe housing by the at least one left pivotable joint member (20a, 22a), the left transducer having a left transducer contact surface; at least one right pivotable joint member (20b, 22b); and, a right transducer pivotably attached to the probe housing by the at least one right pivotable joint member (20b, 22b), the right transducer having a right transducer contact surface; and, wherein the left transducer is free to rotate about a left rotation axis and the right transducer is free to rotate about a right rotation axis; and, wherein the wedge assembly comprises: a left wedge having a left wedge contact surface inclined at a left roof angle to a perpendicular plane, wherein the perpendicular plane is perpendicular to the central plane of symmetry; and, a right wedge having a right wedge contact surface inclined at a right roof angle to the perpendicular plane; and, wherein the left transducer contact surface is in contact with the left wedge contact surface inclined at the left roof angle, and the right transducer contact surface is in contact with the right wedge contact surface inclined at the right roof angle. a left wedge having a left wedge contact surface inclined at a left roof angle to a perpendicular plane, wherein the perpendicular plane is perpendicular to the central plane of symmetry; and, a right wedge having a right wedge contact surface inclined at a right roof angle to the perpendicular plane; and, wherein the left transducer contact surface is in contact with the left wedge contact surface inclined at the left roof angle, and the right transducer contact surface is in contact with the right wedge contact surface inclined at the right roof angle.