This qin is quite an exceptional qin. It is a 25 year old qin, strung with Suxin Silk Strings. The qin was made by master qin maker Pei Jin Bao, born in 1954 April and and currently located in Suzho China. He is also the president of the Suzuo Wu Men Qin Society, and has written several books about qin making. Of all the qin that I have had the chance to play, hear, and take data on, this is probably one of the nicest sounding qin I have come across. The Suxin silk strings are also definitely the nicest silk strings, or any string set for that matter, that I have had the opportunity to play. This data set is very valuable, as it gives a very unique opportunity to look at the harmonic content of such an excellent sounding qin and string combination.
The graphs below are the harmonic content data, spectrograms, and autocorrelation graphs for the tested Sample Qin #3 strung with Suxin silk, with the specified tuning and technique for each data set. You can enlarge the images by clicking on the thumbnails. At the bottom of the page is a brief description of each set of data.
1. Linear Spectrum Harmonic Content Graphs
3. Spectrograms (Window 4096)
4. Spectrograms (Window 2048)
5. Spectrograms (Window 512)
- Linear Spectrum Harmonic Content Graphs – Shows the harmonic content of each string, graphed along the linear spectrum in terms of frequency to intensity. A very accurate way to easily visualize the harmonics and overtones of each string.
- Autocorrelation – Shows the periodic nature or trends from a given set of data. Autocorrelation can provide a unique look at data, and can reveal repeating patterns from seemingly random datapoints. For this application, it is derived from the original signal and more clearly shows the decaying oscillatory nature of the plucked string.
- Spectrograms (Window 4096) – Shows the spectrogram of each string, with a window setting of 4096. This setting allows one to clearly view all of the harmonics by showing the frequency, intensity, and duration of each harmonic. This graph can be most easily cross-correlated to the linear spectrum harmonic content graphs to compare durations and intensities of harmonics in a string.
- Spectrograms (Window 2048) – Shows the spectrogram of each string, with a window setting of 2048. For this application, I have found that this setting is ideal in viewing the oscillatory instabilities of the guqin string more clearly, which cannot be seen as well in higher window settings. These are seen as wavering lines, which are most noticeably present in the mid-upper harmonics.
- Spectrograms (Window 512) – Shows the spectrogram of each string, with a window setting of 512. For this application, I have found that this setting, while having the lowest frequency band resolution of the three settings, allows one to zoom out on the entirety of the harmonic spectrum, and see how the overall power level and intensity shifts from one string to another, and where the harmonic content is overall most present for a given string.