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Instruction and FAQ
How do I use this guitar pickup tone tool...
Can I contact you about this page?
If you are a pickup or instrument manufacturer, we would be happy to speak with you about testing your pickups. Click the Contact button to the left.
If you are an individual in pursuit of that killer tone, we regret we are not able to answer questions on individual pickups or what you should do to get that tone. There are many discussion forums where you can air your questions and even discuss our data.
When will you have data on pickup X?
We are sampling the pickups we encounter and cannot give any dates for having data on a specific pickup.
What good is all this data?
Our pickup comparison database lets you compare pickups technically and audibly. We have measured the responses of many pickups for you, new models and old, and have compiled this information into a free database that you can use in pickup selection decisions.
There are some big problems related to pickup selection. The first is that they are not cheap. Paying a hundred bucks or more for a single pickup is a risky venture. On top of that, it takes an hour or two to install pickups in an instrument. That makes it difficult to do a fast A/B/A/B/A/B comparison. Pickups also sound different in every guitar, being affected by the type of strings and their age, the shape and construction of the instrument, the type of wood, the temperature and humidity, and what the player had for breakfast. For more detail, see our article on The Guitar Tone Equation.
Another problem is that pickup tone is described in the press using the most wishy-washy adjectives imaginable: Brittle, strident, warm, gutteral, biting, smooth, etc. What do these terms mean? That depends on the reviewer's taste, or lack thereof. The fact is, if two guitarists use the same term to describe two different sounds then they mean nothing. Even the less silly terms like darker (less high frequency content) and brighter (more high frequency content) are relative to the listener's ear.
What we need is a way to compare the sounds of the pickups alone, apart from the guitar's acoustic characteristics, and apart from your selection of cheap beer the night before. We have done just that.
With our pickup database, the technical geek can compare frequency response curves, and the tone geek can compare audio samples. Directly.
This tool allows you to view all the curves we have collected for a each pickup, and listen to audio clips. You can easily compare two pickups and listen to the differences in how they sound and see the variations in the response curves.
For each pickup, we tested seven or eight real life scenarios to determine the effect on the response of various lengths of guitar cable and various amplfier input impedances. So each pickup has a family of curves, and you can hear the effect of each of these scenarios with sound clips.
How are similar pickups chosen?
We use a mathematical algorithm on the "10ft low capacitance cable + 500K ohms" curves to select pickups that are similar to each other. The similarity scores are computed such that the lower the number, the better the match. Note that the other curves for similar pickups may be different, so look at all the curves and listen to all the sound clips to get a good idea of whether two pickups really sound similar.
To compare similar pickups, select a pickup of interest on the A side and click the Get Pickup Info! button. Look at the list of similar pickups below the picture. Find one of those pickups in the scrolling list on the B side and click Get Pickup Info! again. Compare the pickups using the graphs and sound clips.
The scores are arbitrary, but a lower number indicates a better match. A number less than 10 is an excellent match. Higher numbers are not as closely matching, as you can see from the graphs.
The similarity is computed from 80Hz to 5KHz, so you might find that two pickups are indicated as matching while the extreme high end responses diverge.
This similarity tool really strips away a lot of the ambiguity regarding the numerous pickup construction factors, and finds pickups with similar output levels and frequency responses. It is very interesting how two pickups can have almost identical responses while having different coil resistances, for example. This could be due to the winding method, wire gauge or magnet type.
Note that the pot resistance also is a factor, so two pickups may have different responses, but look similar due to the pot values in the instrument. Life is never simple, is it?
What are the limitations of this tool?
Our tool is designed to allow relative comparisons of pickups. This tool can not tell you how a certain pickup will sound in a certain guitar, because that is determined as much by the guitar and player as the pickup. However, guitarists doing pickup research are forever asking this question: "I have Brand X pickups in my guitar now, so how will Brand Y pickups sound?" That is a question that we can help with, by providing audible comparisons of how two pickups sound with the rest of the instrument taken out of the equation.
That said, there are several considerations you should be aware of.
First, the audio we used as our test clip was not recorded from an electric guitar, but rather from an acoustic guitar using an internal piezo pickup. Why? The pickup placement on a guitar affects the sound, of course, and using an electric guitar signal as a reference would have colored all the other pickups' sounds. We use a clean and wideband recording for a reference clip so you can hear the full impact of the pickup on the sound.
In one sense, we could have used any audio as a reference since the main purpose here is pickup comparison, but you are certainly more mentally familiary with guitar chords than Louie, Louie.
Second, a pickup in an instrument is affected by its placement along the strings. That's why the bridge pickup sounds different from a neck pickup, even if they are both the same model. There are comb filter effects that have to do with the position of the pickup and the length of the scale. We have not modeled this phenomenon. Generally, a relatively brighter pickup will sound brighter on any instrument, compared to another pickup that you judge to be darker with this tool.
The levels of the audio clips are consistent within one pickup's family of measurements. However, we have not preserved the relative level between different pickups because there is such a range of levels that the lesser output pickups would be misrepresented, or you would have to be changing listening volume to hear all the detail. The graphs do show the raw levels as measured and can be used to compare pickup output. Absolute output level is a factor, but more important is the tonal response of the pickup.
The pickup and pot resistances that were measured in the instrument are approximations. It is difficult making those measurements accurately without disassembling the guitar. But you do get a decent idea of the resistances involved and the frequency responses that result. You should consider the pot resistance when replacing pickups as it does have an effect on tone. If pickup or pot resistances are not shown for a pickup then we were not able to measure them for various reasons.
What measurements have been made?
There are several measurements that have been made on each pickup. Our test equipment loads the guitars and pickups to simulate cables and guitar guts. Here is the breakdown:
Note that we cannot measure the pot or pickup resistance on active pickups due to the intervening amplifier!
How does capacitance affect the tone?
We've written a detailed article on this topic, The Effect of Cable Capacitance on Guitar Tone. But in general, take a look at this Java applet we have written that shows the effects of resistance and capacitance. (If you cannot see the applet, Java is not working correctly in your browser; please investigate this on your own as we cannot debug Java AND test pickups!)
Slide the Capacitance and Pot Resistance controls to see how they affect the frequency response of the pickup. (You may have to zoom the browser window in or out to use the applet!)
When you add more capacitance, the response peak moves to the left, lower in frequency, and the sloping rolloff moves lower as well. The peak also increases in amplitude. The peak sounds like a pronounced increase in volume in the 1KHz to 5KHz area. That's what gives some pickups the nasal, midrange sound. The capacitance slider above also shows how the tone control affects the pickup's response.
The downward slope is a reduction in the high frequencies coming out of the pickup. The more capacitance there is, the more highs you lose. In this graph, moving from a low or zero capacitance guitar cable to a premium high capacitance cable results in 10dB or more loss of high frequencies. You can't recover that with the treble control in your amp.
Decrease the resistance and notice how the height of the peak drops. With the right combination of resistance and capacitance, a flat response can be had, but that's not necessarily where the pickup sounds the best!
The graph also hints at why some pickups sound like they have more low end than others. The ear is more sensitive to frequencies in the 1KHz range than the lower frequencies. When the conditions presented to the pickup change, the player resets the volume and tone controls on the amp to compensate based on what he hears in the most sensitive part of his hearing range, near 1KHz. If the pickup's response peak is reduced, it sounds by comparison like the pickup now has more low end. And in all the graphs we have seen during our testing, the pickup response at the low end is not affected whatsoever by loading or cable capacitance!
How do I select guitar pot resistance to get a certain tone?
You can use the tested resistances to determine the effect on the pickup. A higher pickup load resistance results in a higher output level and a high frequency peak. Lower resistance results in a flatter response with less gain. The Java applet above shows this clearly.
The resistance of the pot in the instrument and the resistance at the input of the amplifier combine using a standard formula. For example, a 250K pot in the guitar combines with a 1 megohm (million ohm) amp input resistance in the following way:
(250K * 1M) / (250K + 1M) = 200K.
So the pickup sees a load of 200K ohms and that helps to determine the tone.
Note that the resistances do not just add or subtract. This formula is called "product over the sum" and is a standard formula that technicians use to compute the resistance of two resistors in parallel. Here are a couple simple calculators to help:
You can find amplifier input resistances (or input impedances) in the spec sheets or on amp schematics. For example, the input resistance of most tube amps is simply the resistor value connected from the grid to ground of the first tube. Here's a snippet of a Marshall schematic showing this resistor, 1M, or 1 million ohms.
Example 1: You have a 350K pot in your Fender guitar, and it's connected to the Marshall shown above with a 1 megohm input resistance. What is the pickup load resistance? Enter 350 in the "Pot Resistance" blank, and enter 1000 in the "Amp Input Resistance" blank, then press Compute. The result is about 259K. The 250K selection for pickup loading will be a good approximation for this level of loading, to compare sound clips between pickups.
Example 2: I like the sound of a certain pickup with a load of 100K. My amp has an input resistance of 750K ohms. What pot value should I use? Enter 100 in the "Desired Pickup Load" blank. Enter 750 in the "Amp Input Resistance" blank, then press Compute. The result is 115K. The closest common pot value is 100K.
Do you have more detail on the pickups you tested?
We have listed all the information we have about the pickups we have tested. Some pickups we cannot identify beyond what's implied by the make/model, serial number and year of the guitar. There are books that give more detail regarding the history of each manufacturer and instrument. The true tone freak will use our database as only one source in his quest for the ultimate tone. Our intent is to present as many pickups as we can and let you find something close to your needs and tastes.
Many guitars are loaded with two or three identical pickups. Our data is marked with "bridge", "middle", or "neck" to indicate which pickup was tested. In most cases this information is of no consequence, but some manufacturers load different but identical looking pickups, and this may help you sort that out.
What about guitar tone controls?
Note that all the tests we did on in-guitar pickups were performed with the tone controls on '10'. We tested one pickup at a time using the switching in the guitar. We ignored coil tap switches and tested humbuckers only as a complete two-coil pickup. If you are modifying a guitar, you can easily try various capacitors on the tone controls to get the response you like.
Why is there such a big difference between single coil and humbucking pickups?
A humbucker has twice the wire, twice (or more) the inductance, and twice the interwinding capacitance of a single coil pickup. This results in greater high frequency rolloff. In fact, the internal capacitance is so great that cable capacitance has less of an effect. However, due to the dual coils, humbuckers have 6dB to 10dB more output than single coil pickups, which equates to more drive for your amplifier. Compare a humbucker and single coil pickup on the graph and you'll see the difference.
This also means that single coil pickups are more 'tunable' by adjusting the cable capacitance, tone control capacitance, and volume pot resistance.
What's with the upward hook in some response curves around 20KHz?
Some pickups have a secondary resonance peak around 20KHz. Others may have an even higher frequency secondary resonance that is not seen because we only measure the response out to 20KHz. Since guitar amplifiers and speakers have little response at 20KHz, we feel this is a negligible effect. However, tone hounds (pardon the canine reference) may want to explore this near ultrasonic phenomenon and compare pickups with and without the resonance. It's more likely that this is a result of interwinding capacitance -- so there's your next weekend project.
Why didn't you use a distorted reference sample?
We used a clean reference because the distortion is produced entirely by the amplifier and speakers and not the pickup, and we cannot control or predict how the pickup will be used.
What is the reference for the level measurements?
The level measurements use a reference that you cannot reproduce without our equipment and thus are arbitrary for your purposes. We have scaled the measurements such that single coil pickups measure roughly 0dB. Once again, this information is good for relative measurements only.
How and why did you collect this information?
We designed a custom device to measure these pickup responses, and it works whether the pickup is in or out of the instrument. This does not consist of a vibrating string rig, as we have seen several of those in use by others. Our measurement technique measures the pickup response only, and totally ignores the acoustic nature of the instrument itself, which would color the results. Beyond that, our methods are being held as a trade secret, so please do not ask technical questions about the measurement methods.
We became interested in this matter while testing our ZEROCAP guitar cables, which have very low cable capacitance and open up the sound of the guitar in an amazing way. In doing some testing to quantify and understand the technical reasons for the improvement in tone, we realized that we could plot pickup responses under a variety of conditions and that this information would be valuable to guitarists.
I wind pickups and your curves look different from mine.
There is NO standard regarding the testing of guitar pickups. We've designed our test equipment to conform to good engineering practice. No doubt you have, too. However, there are numerous selectable conditions under which each pickup is tested, whether on your rig or ours. Those conditions affect the resulting data, as well as any post processing such as compensation for the human hearing response. Once again, the power of this tool is relative comparison of various pickups, using the same testing method to measure each. You can do the same comparisons using your methods, as long as you use the same method to measure every pickup.
Which pickup is best?
There is no such thing! Each pickup in the universe has a purpose. If you play metal, you might want a pickup with less high end, which will sound tighter and cleaner after being processed by distortion pedals and clipping amplifiers. If you play country, you may like a flatter response with more top end. The objective here is to allow you to compare what you have with other pickups. Knowing what you want (more highs, less mids, etc.), you can select possible replacements.
Can you include OUR pickups in your database?
Yes! If you manufacture pickups, you are welcome to send us samples for testing. We'll test them and promptly send them back to you in new condition (assuming they were new!), and make the data available here with a link to your web site.
Can you exclude our pickups from your database?
If it's for sale, it's fair game for inclusion here. We're sampling as many different pickups as we can get our hands on. We're not inclined to remove data that we have taken time to add.
Can I notify you of an error in notation or description?
Yes. Please send a polite email to us using our contact page.
What is the detailed history of a certain guitar that you tested?
Sorry, we don't collect that information.
Gawd! I cannot believe that pickup X sounds so much [different from / the same as] pickup Y! What are you guys smoking?
Lighten up! This tool gives you a little free information about pickup behavior and sound. There are many, many tone factors that cannot be meaningfully measured. The final arbiter of pickup sound is how the pickup actually sounds in the guitar. This database does however provide information that should have been available for the past 50 years. Loudspeaker manufacturers do it, so why not do it for pickups as well? Use this information as you like, and then we'll see you on the cover of the next issue of Guitar Gawd.
Can I play my 1897 Les Paul Cowpatty Special into my iPhone and send you a sound clip to use?
NO! We only are using the one reference audio file at this time. Thanks, anyway, pardner.
What kind of pickups should I be using if I want to play like ________________?
Sorry, we cannot help you with that one, either. That's really not a pickup question!
All data and presentation formats (C)2009-2011 Atlantic Quality Design, Inc. All trademarks are the property of their respective owners, with whom we are not affiliated.
This data is only to be used by guitarists for the purposes of pickup selection. No warranty is offered regarding this information. We reserve the right to maintain this data as we see fit. This technology is patented.