Below are the various sets of data I have collected for a set of Longren Binxian composite strings I have had the chance to borrow for my study. Upon closer examination of the strings, it appears that these popular brand of composite strings are made identically to their metal-nylon counterparts, using a monofilament core, fiber packing, and flat nylon wrappings. These strings use a nylon core, nylon fiber packing, and the mentioned nylon wrappings. These are also made in an identical style to other instruments strings such as harp strings. I will eventually run some tests to compare the harmonic spectrum of these strings with that of actual harp strings of identical construction methods. I will also run comparative analysis between various sets of Longren Binxian strings I have tested and recorded. These strings were previously used.
From my experience so far with them, I actually like this set of Longren Binxian strings, though I still prefer a quality set of silk strings. Personally for myself however, I would rather use these than the metal-nylon strings I have tested at this point, but this is mainly based on my own personal tonal aesthetics. Due to lower tension, they are also easier to string, and for my own qin, which has a softer shellac based finish, they would present less of an issue for surface damage, though still not as low damage to the qin top as silk strings. These strings have a very bass heavy response, less so in the mid and upper range, with simpler harmonics than the silk strings I have tested so far, resulting in a quite warm, but less complex tone. A nice advantage is that one does not need to worry about any upper overtones like several metal based strings out there, without the need for creams as well, although the sound might be too plain for some. They seem to fall nicely in between metal-nylon and silk in regards to volume, tension, and sustain. The surface of the strings feels a bit different however, kind of almost like a slippery rubber feel to them. I also prefer to use them tuned much lower than average, around G#1 for the first string fundamental.
The graphs below are the harmonic content data, spectrograms, and autocorrelation graphs for the tested Longren Binxian strings, with the tuning and technique specified 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.