As a key component in the upright piano sound system, the characteristics of the hammer have a very important impact on the sound quality. By adjusting the characteristics of the hammer in many aspects, a rich and diverse sound quality effect can be created.
First of all, the material of the hammer is the basic factor affecting the sound quality. Generally speaking, it is more common to use wool felt as the covering material of the hammer. The different density and elasticity of wool felt will cause the hammer to produce different timbres when hitting the strings. Wool felt with higher density and moderate elasticity can make the hammer transmit more concentrated energy when hitting the strings, and produce bright and penetrating sounds, which is suitable for expressing exciting and grand music pieces; while wool felt with slightly lower density and better elasticity will make the sound softer and warmer, and can create a delicate atmosphere when playing lyrical and soothing music.
The weight of the hammer also plays a key role in sound quality control. Heavier hammers can give the strings a greater impact when striking them, increasing the amplitude of the string vibration, thereby producing a more grand, deep volume and richer overtones, which is suitable for use in large concert halls and other occasions that require strong sound effects. On the contrary, lighter hammers produce relatively less force when striking, and the sound will be crisper and more agile, which is more advantageous when playing chamber music or expressing delicate musical details.
The shape design of the hammer should not be ignored either. The curvature and size of its head will affect the contact area with the strings and the pressure distribution at the moment of contact. Hammers with smaller curvature and sharper heads have a small contact area and concentrated pressure when striking the strings, which can produce bright, clear and granular timbre, and are often used in the treble area to highlight the brightness and clarity of the treble; while hammers with larger heads and gentler curvature have a large contact area and relatively dispersed pressure, which can make the timbre more rounded and full, and are mostly used in the mid-bass area to show a mellow sound quality.
The hardness of the hammer is also an adjustable feature. The hardness of the hammer is changed through a special processing process. The hard hammer can make the strings vibrate quickly, producing a crisp, bright and fast sound quality effect, which is suitable for fast scale and arpeggio performance; the soft hammer will make the strings vibrate relatively slowly, producing a softer, warmer and longer sustained sound, which is suitable for lyrical slow movements.
In addition, the relative position and movement trajectory of the hammer and the string will also affect the sound quality. Accurately adjusting the position of the hammer's striking point and selecting the appropriate striking point in different sound zones can optimize the vibration mode of the string and make the timbre of each sound zone more balanced and harmonious. At the same time, ensuring the accuracy and stability of the hammer's movement trajectory can ensure that the force and angle of each strike on the string are consistent, so that the sound quality performance is more stable and reliable.
In the process of piano manufacturing and later maintenance, the piano maker can comprehensively adjust the above characteristics of the hammer according to the design purpose of the piano, the performance style requirements and the personalized requirements of the customer, and finely control the sound quality performance of the upright piano, providing the performer with a rich and high-quality sound selection, so that the piano can show its unique charm in the interpretation of various musical works.
