Crusader Posted July 12, 2010 Report Share Posted July 12, 2010 The Neck Pickup Sweet Spot Several weeks after I bought my first Les Paul in 1977 I asked the shop owner why they don't make them with 24 frets and he said the neck pickup needs to be where the 24th fret would be to get the best sound. I thought he meant it has to be in that exact location so I was very skeptical. At another shop a few months later I heard a young salesman talking about the same issue and he said it was just distance from the bridge I decided the only way to find the truth is to do my own experimenting and now I have done what I wanted to do all those years ago. I studied the Harmonic Series and compared pickups in different positions on three different guitars to arrive at my conclusions and I am convinced they are correct Here are a few websites that cover the topic of the Harmonic Series and some of them touch on what I am talking about but I still haven’t found any that actually give a complete explanation http://wapedia.mobi/en/Harmonic_series_(music) http://www.physicsclassroom.com/Class/sound/U11L5b.cfm http://www.gmarts.org/index.php?go=233 Most of my experimenting was on this guitar which I routered to get a pickup on the second octave where the 24th fret would be (I will call this position A) Before that I could only get it where the 26th fret would be (I will call this position First I moved a middle pickup in stages to position B which is 42mm and it was only slightly warmer each time. In other words position B just sounded like a warm middle pickup Then I moved it 10mm further and noticed a significant change in tone as well as a steep increase in warmth. Finally another 7mm at position A the sound had completely changed to a clean rounded tone which seemed to cover the whole fretboard To me this proves there is a sweet spot but the location does not have to be exact Next I installed a modified PAF which has adjusting screws on both coils to get a back to back comparison of position A & B Coil A went from the open string to the 19th fret and was especially sweet at the 12th fret (Above the 19th fret sounded the same as the bridge pickup) Coil B went from about the 4th fret to the 21st and sounded nicer at the 14th fret (Above the 21st fret sounded the same as the bridge pickup) Although Coil B had this rounded tone it was not as nice as Coil A except at the highest frets. This diagram depicts the sound quality of each coil So these simple tests indicate what I was told 33 years ago is quite true but what is so significant about the second octave? It is also the antinode of the second harmonic of the open string which would have a lot to do with warmth but what about the "clean" sound? When I played a 5th fret harmonic tuning up with Coil A there was no sound from the amp and I thought it had blown a fuse. I have always known the neck pickup is not the best for harmonics and I have heard people talk about cancellation but did not expect this After studying the Harmonic Series for each fret I found there is always a node on or near the second octave so they would be cancelled or very faint At the open string the fourth harmonic is cancelled When you play the 1st fret the fourth harmonic is still virtually cancelled When you play the 2nd and 3rd frets the fourth and third harmonics are both very faint At the 4th fret the third harmonic is virtually cancelled At the 5th fret the third harmonic is fully cancelled At the 12th fret the second harmonic is cancelled then it goes back to the third then fourth harmonic at the 19th fret So this means the distance from 19th fret to pickup is quarter of 19th fret to bridge. It has the same relationship to the pickup as the open string Obviously a pickup in any position will cancel overtones (along with every harmonic above it that has a node at that point) but at the second octave it cancels the lowest-order harmonics possible so you get the most cancellations. If you remove all the overtones you end up with just the Fundamental which is known as a "Pure Tone" http://www.wordiq.com/definition/Pure_tone I found where you get the best sound (see diagram 2) is also where the most cancellations are but it also depends on which harmonics are cancelled At the 12th fret every second harmonic is cancelled A A E A C# E G A B C# D E F# G G# A This means you never hear the octaves of the fundamental so it is closest to a Pure Tone and sounds the best At the open string every fourth harmonic is cancelled A A E A C# E G A B C# D E F# G G# A At the 5th fret every third harmonic is cancelled D D A D F# A C D E F# G A B C C# D You hear every octave of the fundamental so it is less of a Pure Tone and is probably why it does not sound as sweet as the open string or the 12th fret So to sum it up in a brief explanation "A pickup at the second octave cancels lower order harmonics leaving the fundamental of most notes on the fretboard as an almost pure tone" I hope I haven’t gone overboard with this explanation but there are still other factors I have not mentioned Quote Link to comment Share on other sites More sharing options...
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