Some examples of waveforms with the same power spectrum, different phases

[Joe Gwinn]

Joe and Mike

When I put my communication theory research hat on it appears that humans have evolved to separate the random nature of noise from the more harmonically unified nature of music which is more pleasing. This is complicated by the fact that a cannon shot can be considered noise but when well timed in a musical sequence, it can enhance a musical phrase and be considered musical.

It's true that we somehow evolved to hear some things as musical, but nobody knows why. There is little mystery about the acuity of vision coupled with hearing to maintain situational awareness, as this is very useful in avoiding being eaten, surely a priority.

But the reason for music to exist has been a mystery since ancient times. There is no obvious evolutionary reason that music must exist.

Oddly, many animals seem to react to music. Many farmers swear that classical music calms the milk cows.

Guitars were initially located in the rhythm section of big bands where only the initial quick attack of chords could be heard integrated into the rhythm patterns and add a subtle flavor to the sound. Over time guitars were amplified to allow guitars to be heard over the other instruments and even become featured lead players.

Almost everyone can tell the difference between an acoustic guitar sound and an electric guitar sound. The key research issue is what part of the guitar sound make the most difference in telling what type of guitar created the sound. I believe that the initial attack of the note or chord reveals the fingerprint of the sound source, acoustic or electric.

One test to confirm this would be to record the same sounds made by both acoustic and electric guitars and shorten the sample until it is difficult to tell the difference between acoustic or elecrtric sound sources. This will help confirm that the initial attack of a musical sound helps fingerprint the identity of the sound source.

As electric guitars evolved, adding clipping and distortion allowed guitars to sound like other instruments where the initial attack is less important, such as a sounding like a violin or a saxaphone or even a pleasing modulated sound wave.

Interesting history. It would be reasonably easy to test the attack theory by editing test sound tracks on one's computer.

High impedance guitar pickups have some interesting characteristics that may help to explain why the initial attack as it is harmonically related to the more immediate sustain is critical to accurately identify a sound source.

I'm not sure it's that complicated. After all, we can quite accurately tell the direction of a twig snapping underfoot, or even a rustle in the leaves. Probably has something to do with the dietary desires of tigers.

Early guitars were plugged into early PA amplifiers combined with a speaker in the same cabinet. This required the pickup to put out about 100mv to 200mv to adequately drive the input stage. The consequences of 5,000 to 6,000 turns of wire creates a pickup in the 2H to 4H range with coil winding capacitance and a guitar cable coax capacitance forming a resonance in the hearing range where the human ear is most sensitive.

So, that's why! I always wondered. An added amplifier stage meant an added vacuum tube, and Leo was cheap.

Another consequence of this design is that the pickup coil is very low Q with DCR in the 5,000 ohm to 7,000 ohm range and a time constant (TC) defined by the coil inductance divided by the DCR. I believe that how the attack TC stays harmonically related to the sustain/decay sound also helps fingerprint the sound source (acoustic or electric) and also helps define what we perceive as pleasing.

One piece of support for the attack theory is that pickups with a high resonant frequency sound clearer.