Post by antigua on Sept 3, 2017 1:37:35 GMT -5
With a reliable plucking scheme worked out, as described here guitarnuts2.proboards.com/thread/8001/string-plucking-mechanism-consistent-testing , and a kick butt audio analysis tool in the form of Adobe Audition, I can't think of enough tests to conduct.
Here is an analysis on "wolf tones", or "stratitus", where the magnetic pole piece of the pickup pulls so hard on the string that it induces an inter-modulation, or two notes on the same string that "beat" together to produce an out-of-tune sound with frequency beating.
What I've done for this test is, in order to induce strong wolf tones, I've put a capo on a Strat at the 12th fret, and I'm plucking the low E string. This puts the neck pickup directly below the center of the moving string, allowing the AlNiCo 5 pole pieces to pull at the string where it has the least amount of stiffness. There are six plucks in the wave file below. It start out with the pickup far from the string, and with each pluck, the pickup is raises closer to the strings until, by the last two plucks, where the pickup and string are very close, the "wolf tone" is loud and clear.
As the pickup comes closer to the string, and the "wolf tone" becomes audible, you see a second pitch develop a few hertz below the fundamental and harmonics. The second pitch not only increases in relative amplitude, but becomes lower in frequency, so the beat frequency (the rate of the "wah wah wah" sound) increases as a result.
www.echoesofmars.com/misc/wolf_tone_plucks.wav
Using Adobe Audition's frequency selection, below is a demo of those two final tone selected in isolation, and then together.:
www.echoesofmars.com/misc/wolf_demo.wav
First you hear an E3 at 164Hz, then the intermodulating wolf tone roughly 6Hz below the E3 (almost to an E flat), then you hear the two put together.
Here is an analysis on "wolf tones", or "stratitus", where the magnetic pole piece of the pickup pulls so hard on the string that it induces an inter-modulation, or two notes on the same string that "beat" together to produce an out-of-tune sound with frequency beating.
What I've done for this test is, in order to induce strong wolf tones, I've put a capo on a Strat at the 12th fret, and I'm plucking the low E string. This puts the neck pickup directly below the center of the moving string, allowing the AlNiCo 5 pole pieces to pull at the string where it has the least amount of stiffness. There are six plucks in the wave file below. It start out with the pickup far from the string, and with each pluck, the pickup is raises closer to the strings until, by the last two plucks, where the pickup and string are very close, the "wolf tone" is loud and clear.
As the pickup comes closer to the string, and the "wolf tone" becomes audible, you see a second pitch develop a few hertz below the fundamental and harmonics. The second pitch not only increases in relative amplitude, but becomes lower in frequency, so the beat frequency (the rate of the "wah wah wah" sound) increases as a result.
www.echoesofmars.com/misc/wolf_tone_plucks.wav
Using Adobe Audition's frequency selection, below is a demo of those two final tone selected in isolation, and then together.:
www.echoesofmars.com/misc/wolf_demo.wav
First you hear an E3 at 164Hz, then the intermodulating wolf tone roughly 6Hz below the E3 (almost to an E flat), then you hear the two put together.