Pickups: The 2008 Results
The Step Coil

Pickup Video 8: Web Journal Version
Pickup Video 8: YouTube Version

Above is the step coil I built by pulling a loop out every 1000 winds as I made a 10K coil. Each loop was cut to create an "in" and "out" wire, which is soldered to a thicker color coated wire. These go into the connection strip. I can connect the cable leading out to the amp to any set of in and out connections to check the sound from 1k to 10K, as well as dual coil setups to test phase cancelling arrangements, or "humbucking". Actually, two of the loops were damaged somehow, but I was able to jump over them and still have a step coil covering 1K to 8K. The foil is for sheilding and is connected to the ground wire in the output cable, which has its own foil shielding as well.

The actual coil is about 18' and uses 1/4" square ceramic bar magnets attached to the outside edges of the coil, both sides oriented North up.

Impedance: This is the measure of resistance, in Ohms. I used a regular mutimeter for this, so the readings are approximate. I am not sure what the significance of this is, but they list this for guitar pickups, so I did too.
1K: 7200 Ohms
2K: 12,800 Ohms
3K: 19,000 Ohms
4K: 25,000 Ohms
5K: 30,000 Ohms
6K: 36,000 Ohms
7K: 49,000 Ohms
8K: 55,000 Ohms

The pickup was mounted between the bridges to interact the greatest range of tones, from lowest bass to 5 noted below the highest note. The test consisted of recording five different tracks at each step.

1. I run up the entire range of notes, first on the right hand bridges, then on the right side of the center bridge, damping each string with my finger before striking the next string above, resulting in two sets of ascending notes.
2. I play a D chord across the same set of strings, using the typical patterns of arpeggios, runs, and walks I use. Because I am entirely on the right side of the center bridge, I am restricted to the low and midrange notes, except for one high D.
3. I play a C chord the same way, but this takes me into the highest ranges available on this side of the bridge, and takes me to the absolute lowest note and the far right bridges.
4. I play a short bit of regular rhythm with the chords D-C-G-D, D-C-G-D, Am-G, Am-G-D
5. I another short rhythm track with a different beat and chords G-Am-C-G

Then I mixed the recordings to play each step in order for each test-track recorded for comparisons. Then I ran the .wav files through a spectral analysis program, the results of which are displayed below with the link to the sound recording.

The problems with the test were that there wasn't a constant input, I could only try to be as consistent as possible, so there can be no exact one to one comparison, both in volume and what notes are played, except for the scale, and even there volume isn't consistent. Also, because the bridges and strings aren't yet optimized for the placement of the pickups, some of the bass strings are too close to the pickup, a few (you can hear in the scale track) are too far away. Still, that is consistent track to track.

Full Scale Test Track

Play Audio Track

As expected, the full 8 step test showed me the best response range, which was from 4 to 7K. So I only am showing you the full 8 steps in this first scale test. The other tests are limited to the 4 to 7K range to save space and time. The basic changes as I step through the coil seems to be the amount of bass response slowly increasing, and the total frequency range in the upper harmonics first increasing, peaking at 5 to 6 K and then diminishing again. Of course, the whole pickup incrases in volume as the number of coils increases, increasing the signal to noise ratio. I left the relative volumes as recorded so you could hear the relative increase. Note that after I damp the string with my finger and before I strike the next note, you can hear those high harmonics ringing. And the Bass sounds the way I keep telling the sound techs it should sound, like thunder.

4K to 7K Scale Test Track

Play Audio Track

Here is just the 4K to 7K part of the scale test, if you want to listen to it more. From here it is a more difficult choice, since there is not nescessarily a "perfect" number of winds, but more an acceptable range. Frankly, without the spectral analyser, it is hard to tell the difference with all the variation in mt playing, but the results seem to be that 5K to 6K produces the best range of frequency and the best balance of bass and treble.

Key of D Test Track

Play Audio Track

Key of C Test Track

Play Audio Track

D-C-G-D, D-C-G-D, Am-G, Am-G-D Test Track

Play Audio Track

G-Am-C-G Test Track

Play Audio Track