The sound of the piano is melodious, like a gossamer; the sound of the piano is soothing, like silk; the sound of the piano is low, like an ancient bell.

The timbre is the highest criterion for the selection of the quality of the guqin. Therefore, qin masters of all dynasties and generations have put forward their personal opinions on the selection of guqin. The earliest discussion of the beauty of the sound quality of the qin was Ji Kang's "Qin Fu", which said: "The instrument is harmonious, so the sound is clear, and the sound is clear in the Liao; The sound of the piano should have the characteristics of "Yi", "Qing", "Bo" and "Ming".

In the Song Dynasty, Cui Zundu put forward the four characters of "Qing", "Harmony", "Quiet" and "Far" to express the characteristics of the piano sound. Fan Zhongyan recounted this incident in the "Book with the Tang Sergeant", in which he said: "A certain taster traveled under the door of (Cui Zundu), and one day asked him: 'Why is the qin?' Far.' A certain bowed and retreated, thought and released, saying: 'Clear and stern but not quiet, its loss is also irritable; and moist but far away, its loss is also ren (nìng). Be rash and ruthless, and then the gentleman, among them, is harmonious. Daoyi?'"

In the Ming Dynasty, Leng Qian put forward the theory of "Four Goods" and "Nine Virtues" for the first time, among which the "Four Goods" are green, loose, crisp and smooth; , Even, clear, fragrant. This argument is found in Leng Qian's "Sounds of the Ancient Times: The Nine Virtues of the Qin", which states:

"One is called 'Qi'. Those who say light, loose, brittle, and slippery can be called 'Qi'. Those with a light cover are light in their material; those with a loose cover are buckled and their sound is transparent, and the material is long-term; The wood is tight and the sound is clear and long, and the cracks are broken, and the wood is old;

It means that the standard of a good qin is "light, loose, crisp, and slippery", and this statement was first put forward by Shen Kuo in "Mengxi Bi Tan" in the Song Dynasty, and called it the "Four Goods".

"The second is 'ancient'. It is said that there is a golden and stone rhythm in Chundan, and the place where Gaiyuantong is produced is also natural. If there is Chundan tone but no golden and stone rhythm, it is almost turbid; It is only clear. The two are prepared, which is called 'ancient'." (Leng Qian, "Ancient Voices")

The basic meaning of "gu" is that the sound of the piano must be clear and turbid, which is closer to the meaning of "harmony". In other words, we can also understand that the sound of the piano should be mellow and dilute, without impatience, but also with a clear spiritual atmosphere.

"The third is 'penetration'. It is said that the years are long, the rubber knees are dry, and the sound becomes louder without being blocked."

The "penetration" here is not only an important criterion for measuring old pianos, but also an important criterion for evaluating new ones. Only after a long period of time, the glue and lacquer in the piano material have dried, and the sound of the piano can be unimpeded.

"Fourth is 'quiet'. It is said that there is no killing and shattering the sound." (Leng Qian's "Sounds of Ancient Times")

The "quiet" here is somewhat similar to what we call "jing" today, that is, there is no rustling sound. This requires the violinist to have a good level of craftsmanship, especially the panel should be clean and the curvature should be precise.

"The fifth is 'running'. It means that the voice is not dry, the rhythm is long, and Qingyuan is lovely."

"Running" is the antonym of "dry" and "dry". It can maintain the quality of "running" for a long time, and it also requires extremely high qin craftsmanship.

"The sixth is called 'round'. It means that the sound and rhythm are smooth but not broken." (Leng Qian's "Ancient Voices")

"Circle" refers to the roundness of the sound on a string, that is, the sound between each sound on the same string is uniform, not some sound is transparent, some sounds are not transparent, and some phonemes are Sa sound, some phonemes have no Sa sound.

"The seventh is 'Qing'. It is said that the voice is like a duo in the wind." (Leng Qian's "Ancient Voices")

The sound of the piano should be like the crisp sound of a copper bell blown by the wind. "Clear" is the opposite of "turbid" and "turbid."

"The eighth is called 'even'. It means that the seven strings are all clear and round, and there is no disease of the three realities and the four emptiness."

"Even" means that the dispersion, pressing, overtones and all sounds of the seven strings are evenly distributed.

"Nine is called 'Fang'. It means that the more you play, the more the sound will come out, but there is no disease that the sound is lacking for a long time."

That is to say, when playing, the sound should be unified before and after, the volume and timbre should not change from beginning to end, and the better the piano should be played, the better it sounds.

Nowadays, the saying that "qin has nine virtues" is very widely spread. When people choose a guqin, they will decide according to this standard. However, due to various problems such as different woods and different qin craftsmanship, the qin that Jiude has In fact, it is very rare. An ordinary guqin can be considered as a rare good qin if it can be quiet, transparent, round, moist, clear, and even.