How a pickup works
How Pickups Work
The sound of your electric bass is greatly dependent on your pickups. There's a lot of misunderstood and outright misinformation floating around about how they work and what they do, but they are really pretty simple devices. The simplest designs are basically just magnets with a lot of really thin wire wrapped around them. Your guitar string becomes part of the magnetic field generated by the pickups magnet, and when you play a string, the magnetic flux changes, and a voltage is induced in the coil that is proportional to the strings velocity. Now you just need to send this signal to your amp to make it louder, and voila! You're in business!
How Pickups Are Measured
Every different pickup on the market sounds different. Really, its not that pickups have a sound, rather, they each hear different frequencies more or less than others. The frequencies that a pickup hears can be plotted on a chart called bode plot.
On the chart above, you can see that that there is typically a frequency that is louder, or heard better, by the pickup. The frequency that a pickup hears best is called the resonant frequency. In the example above, this frequency is about 8.5kHz. The height of the resonant frequency is called the Q, and in the example above, is about 8 decibels. The location and the height of this resonant frequency is what gives a pickup its unique voice. So, the pickup above, will have a lot of treble content that is pretty apparent. Once you know the location and height of this resonant frequency, you know at least 90% of what a pickup will sound like, and this is the secret to a pickups unique sound. The strength of the magnetic field and the distance between the 2 coils (if there are 2 coils, like a humbucker) aren't represented by this graph, but their affects are smaller.
What Pickup Designers Do
When pickup makers change different aspects in their designs, they're putting the resonant frequency in a different spot, and thereby giving it a different voice. They are raising or lowering the resonant frequency, and raising or lowering the Q. They can do this by changing the number of winds of wire, changing the diameter of the wire, or by charging the type or amount of material in the core of the pickup.
The Whole Guitar
Your pickup is really only a part of the entire system that determines the final voice of your guitar. It may be the biggest part, but other components also affect things. The value of your volume and tone pots play a big role in this. The resistance that the pots have affects the size of the Q, or the height of the resonant peak (how apparent sounding the peak is). The lower the value of the pots, the more the peak is lowered. Single coils typically use a low value pot, like a 250k, in order to tame them down, because single coils typically have a high Q and sound very trebly. Humbuckers on the other hand, typically use a higher value pot, like a 500k, because the pickup usually already has a lower peak and not as much treble content, so a higher value pot is used to maintain more treble.
Your guitar cable also plays a big role in this. Guitar cables have a certain amount of capacitance built into them, and this is typically a lot more than the pickup. So, a long cable, with a high capacitance, can lower the resonant frequency (shift the peak to the left). Your brilliant pickup will get muddied down by your favorite long guitar cable!
There are other parts in your guitar that have some capacitance and resistance as well, but the cable and pots are the biggest ones.
The problem with picking out new pickups
You've probably determined by now that picking out the right pickups for you and your bass is no easy task. You need to know what the resonant frequency and the Q is of the pickup if you want to know what it will actually sound like, but these numbers and plots are typically not available, if they are even known! Plus, you need to know how much your bass will affect these values. Further, a well constructed bass with fresh strings will sound entirely different than a poorly constructed bass with old strings.
Simply put, a pickup that sounds great in one bass, may sound entirely different in another due to all of the variables.
To make all of this worse, most pickup companies sell their pickups using a lot of descriptive words that really don't tell you anything about what the pickup sounds like. Terms like "Thick lows", "Sparkling Highs" or "Grunty Mids" don't really mean anything and all may be used to describe the same pickup!
Variable Voice Pickups are the Solution
We designed the new VV series to solve all of the issues with picking out the right pickups. Using passive circuitry that's built right into the pickup, the VV series allows you to tailor the resonant frequency and the Q to whatever you need. They eliminate the guess work out of picking out your pickups because they can be tailored to match your instrument and the sound that you need. The same pickup can be dialed in to have a very detailed, hi-fi type sound, or dialed to have a very warm old-school type of tone.
Parameters
Resonant Frequency. This is the frequency that your pickup hears the best. This frequency is louder than the other frequencies in your signal and is the voice of your pickup. There is essentially an accent made by your pickup at this frequency.
Q. The Q, also called the Quality Factor, is the height of the resonant peak. This is how apparent the resonant frequency is compared to everything else. High Q's are very distinct, while low Q's are smoother or duller.
Inductance. Inductance is a measure of how efficient your pickup is. Higher inductance means a louder pickup, but it will also move the resonant frequency lower, while also lowering the height of the resonant peak.
Capacitance. Capacitance is a really a measure of the ability of an electrical device to store energy. Inside of a pickup, there isn't much capacitance, but the higher this goes, the lower the resonant frequency.
Resistance. This is a measure of how much resistance there is in the coil wires. If you know how thick the wire is, it tells you how much wire was used.
Wire gauge. This is a measure of how thick the wire is that was used to make your pickup. Thicker wire typically yields less capacitance and resistance.
The Parts and Their Affects
Variable Voice Series, How They Work
The Variable Voice (VV) series was designed to give you total control of your pickups response and overall tone.
How they Work
The VV series has passive circuitry built right into the pickup that allows you to shift the location and height of the resonant frequency (RF) of the pickup. The RF is what defines a pickups voice, and is the secret to a pickups overall tone.
There are 2 dials that are accessible from the top of the pickup.