Magnetic pickups, both single-wound and humbucker, are becoming a more and more popular addition to a CBG build. Both are now inexpensive and offer several advantages in terms of tone and absence of unwanted box noise.
Installation is relatively easy: Cut a slot in the neck for the pickup (assuming you aren’t already building stepped neck assemblies), reinforce the cutout slot, cut a hole in the box and you’re good to go.
……….or are you?
Most of us are aware of the significant differences in the tone and volume of a piezo pickup depending on the location and method of mounting. So, is location of a magnetic pickup also important to the sound quality?
Recently, two of your number (Uncle Fred and Tom T) corresponded and collaborated on this question. Using the instant gratification of email and the free-for-all recording software “Audacity” we were both able to perform independent tests and compare results.
Using 3-string CBGs, built to 25" and 25.5” scales and tuned to GDB, we set out to try to determine the position of the pickup along the length of the neck that would provide the cleanest and most balanced sound. Tests were performed with both single-wound and humbucker pickups.
To simplify testing, both guitars were tested with the tops removed. Pickups were secured to the offset neck with rubber bands to allow for quick movement up and down the neck. Tests were performed with pickup positioned down the neck as close to the bridge as possible then moved up the neck in one inch increments to as much as seven inches from the bridge.
The test procedure was to perform single “plucks” of each string at different fret locations using the bare thumb followed by a strum test. Tests were recorded using Audacity so that results could be shared and compared for consistency.
As might be expected, locating the pickups close to the bridge subdued the bass notes and produced an amplified, penetrating treble. The strong treble tones produced a sound similar to a typical piezo without any tone control applied.
Moving the pickup toward the neck in one inch increments gradually dampened the treble and amplified the bass. Locating the pickup far up the neck (in the six to seven inch area) produced an overpowering, bass and less intense treble.
The Sweet Spot:
Realizing that the clear, balanced tone lay somewhere between the extremes, we carefully tested, recorded and compared information at each location from one inch north of the bridge to six inches north of the bridge. Sound quality was compared using Audacity files emailed back and forth.
Gradually, the range was narrowed and agreed upon. Both the single-wound pickup and the humbucker produced the most balanced base/treble tone and the cleanest tone when centered approximately 3 ¾” from the bridge.
Location matters. While tone controls on amplifiers, effects devices or pre-amps might be able to adjust the tone when the pickup is located at a position other than that noted, it was our feeling that starting with the cleanest best balanced tone possible is an advantage allowing more creative use of external tone-modifying devices. So, as with real-estate, it’s all about location.
TomT & Uncle Fred
im in the mag pickup fan club. piezo's have a place but mags win hands down.bare finger pickin palm heal muted or neck with my pinky planted. i like to pluck right over the pickup.
yes indeed .. this is why in the 60's you saw alot of 3 and 4 etc.. pickup guitars .. many of which had the same output on each pup .. unlike the mixed bridge and neck readings you see today .
and it was not only the individual pickup placement producing different sounds , but the choice of combinations also .
not just cool ,, they had a function and reason .
i may be guilty of going beyond reason tho ;-)
can't take credit for the carving .. that's an empty carved body i got off " low budget lutheir" , after he shelved it for not working with his original design .
What about all the people that don't build to the "standard" scale?
For extra points:
What is the ratio of optimum pickup placement to scale length for the described cleanest and most balanced sound?
What are the ideal locations for additional pickups with the goal of clean balanced sound in mind?
Give answers in the form of a percentage.
But seriously the first sweet spot is going to fall into the 12.5% - 15% of the scale length from the bridge.
indeed we "could" get into nodes and anti nodes , harmonics in scale, and squawk spots .. etc ....
but ... in cbg reality , the "DPGRT" technique is good enough for most of us . ("dats purdy good right dare ") ;-)
but .. if curiosity is killin ya , have a read folks .
Great link Pick.
We came across a number to technical articles about pickup placement such as Pickup Location. The were helpful in figuring out what we were seeing on Audacity tracks, but some of them went well beyond my pay-grade in terms of technical depth. Good reading, but I walked away scratching my head. In the end, we decided to go with our ears and see where it went.
As you can see, we ended up at 15% of scale length through blind testing. Guess it confirms that location. We set out to find the single clean point for one pickup with no thought to multiple mag pickups. The KISS principle was our guide.
One thing we did find odd was that of all the commercial guitars hanging on the wall at Guitar Center, none seemed to have a pickup in the "sweet spot". Guess with blending, things work out, but if a CBGer tried to use those as a guide for placement of a single pickup, the results would be questionable.
We found we could tweak the sound a little bit by slanting the pickup. I you wanted more bass and less treble then slant the bass side of the pickup toward the neck while keeping the middle of the pickup on the "Sweet Spot".
We were comparing the tones at fret positions 0, 5, 7 & 12. The balance of the three strings tones was a little different as we moved up the scale.
The "Sweet Spot" we found to be located at about the 33rd fret position of our test guitars or about 15% of the scale lengths of 25.5" and 25". We did not test other scale lengths.
Our test was not a theoretical mathematical calculation. We simply independently listened to the tones and used "Audacity" to record and compare them back and forth. The "Audacity" plots were also useful to visually compare the sound curves.
We hope this will help some folks with locating their pickups for the cleanest sound.
After listening to one of my 3-strings with the pickup located on the "Sweet Spot" my neighbor said "if I was in the other room and couldn't see the box guitar, I would have thought you were playing a high end commercial guitar". Needless to say, I was pleased to hear this. - Uncle Fred
We published our experiment mostly to help those building CBG's that wanted a clean sound that didn't really want to do the experiments themselves. For those that want to tweak their sound or are curious, the methodology we used would be a reasonably scientific approach.
It was not difficult to create a "test" guitar. We just made our regular offset neck guitar with a partial or no top. When we get tired of testing we can just put a top on it and as Patrick says "play the thing".
We notice that not many CBG's have the pickup located in the middle. As a result of our experiment, we think that if a player wants the cleanest sound from the CBG, the middle location will delight most listeners.
Thanks for you input!
Wayfinder, you are right. that would work at the "0" fret.
We found that the balance of tones between the strings was a little different at various fretting positions. So, to get the whole sound picture, we needed to fret up and down the neck. For me, an older guy, it was near impossible to fret, pluck strings and hold the pickup at the correct location and height at the same time. A simple alternative that I think TomT used in the beginning, was to make a little bridge to hold the pickup at the right height and tape it in location on the top while playing.
It took us some extended playing to narrow down our "Sweet Spot".
This has been an interesting experiment. Have fun!