Frets. Next I'll share some ideas about frets from professionals such as Tom Anderson, Roger Sadowsky and Dan Erlewine, who are some of the best luthiers in the world when it comes to building, optimizing and setting up guitars, and from whom many of us have learned; I recommend taking a look at their work.
Frets can influence both sound and feel, especially the latter. What is decisive, even more than fret size, is how they are installed, because a string resting on the least possible material at the center of a well-rounded, polished fret will give the best possible tone, as well as accurate intonation and greater ease of bending. Conversely, if the string contacts a wider, flatter surface, notes lose clarity and definition, bends take more work because of the greater friction between string and fret, and intonation is less accurate.
In recent years the trend among leading builders has been to fit wider, taller frets, the so-called jumbos. When properly installed, these frets provide somewhat more sustain and, since they allow a higher string height over the fretboard and body, they also affect tone, adding more clarity and definition.
From personal experience I must recommend that guitarists try a type of jumbo fret with a profile between oval and triangular, which makes the top narrower than a traditional jumbo but gives you the best of both worlds. For bass players I would recommend trying narrower frets with the greatest possible height. Many of the most prestigious electric bass professionals use mandolin frets, which are the narrowest available on the market; there's nothing like an old Jazz Bass with narrow, tall, well-rounded frets.
Bridge
The bridge is one of the key elements in defining the sound of a guitar or bass, and how it contacts the body determines how much of the strings' vibration is passed to the body. Fixed bridges have more contact surface than tremolo bridges, so more vibrational energy is transmitted to the body. A guitar with a fixed bridge usually has a deeper, more direct sound than a guitar with a tremolo.
Tremolo bridges are attached to the body by two pivots or several screws, which are the only points through which vibration is transmitted; fixed bridges, however, except for those used by Gibson, contact the body with their entire base, so it isn't hard to imagine why they transmit more vibration.
As for tremolos, from both my own experience and that of others, I've found that one of the best combinations for stability and the best possible tone is to use the tremolo with locking tuners and a perfectly fitted synthetic nut (Graph Tech, Delrin), because the typical metal locking nuts tend to bring a loss of definition, due to the nature of the material and how they affect string tension. Some manufacturers, through a wise choice of components, get guitars with very good sound despite using the double-locking system.
The material the bridge is made from is another important factor; a bridge built from a single piece of steel will “sound” much better than a bridge made by pouring molten metal into a mold. Likewise, the material of the tremolo block, the part where the springs attach and the strings are housed, is another important thing to look at. Like the rest of the bridge, it's best if they are made from a solid piece of steel or aluminum, the latter being Trev Wilkinson's favorite (see the interview in ISP April 09) because, according to him, it lets more frequencies through with minimal “coloration”; when this comes from the most popular guitar hardware designer in the world, it is, to say the least, something to take into account.
The pressure the strings exert on the bridge saddles is also very important; more pressure favors sustain and definition. The bridges that allow more pressure at this point are those with strings anchored through the block, and the ones that allow the least are those with strings locked at the saddle itself.
All these aspects are hard to evaluate and verify unless you try different options on the same guitar. From my experience replacing low-quality bridges with better ones on cheap guitars, I can tell you the difference is more than noticeable.
Scale Length
Scale length is the distance from the point where the string rests on the nut to the point where it rests on the bridge, and depending on this length, feel and sound are influenced one way or another. The most popular measurements, in inches, are 24.75 (Gibson), 25 (PRS), 25.50 (Fender) and 34 (electric basses); musicians generally get used to playing one scale length and usually don't want another. As a general rule, and this is something the vast majority of builders seem to agree on, long-scale guitars favor more defined notes, while short-scale ones have a stronger mid response and a less defined sound, but with a faster attack. An interesting alternative is the 25-inch scale used by Paul Reed Smith, since it combines the best of the two traditional lengths, in both sound and feel. On electric bass the most common length is 34 inches; so-called short-scale basses are 30 inches, are very comfortable and easy to play, but the definition of the lowest notes suffers. One option if we want a somewhat more comfortable bass is to use a 32-inch length, which works for a four-string bass in standard tuning. On five-string basses it's not unusual to use a 35- or even 36-inch length so the fifth string sounds more defined, although this can be achieved with 34 inches if the appropriate construction type and string gauge are chosen. In general, with basses that are strung through the body, have an angled headstock and use a heavy string gauge, a defined sound can be obtained on the lowest notes.
Pickups
Pickups, along with strings, are the components of the guitar with which it is easiest to manipulate an instrument's tone. What pickups do is capture the acoustic sound of the guitar or bass and reproduce it, adding a characteristic color according to the pickups' properties. You can't easily increase a guitar's output or emphasize a certain frequency by swapping hardware, but you can by choosing the right pickups. It's important to be clear that pickups won't make up for shortcomings in sound, nor are they the main element in creating an instrument's tone; their job is to bring out the best in a guitar, which is why it is important to choose the type of pickups properly, taking into account the instrument's acoustic properties and the musical style it is intended for. Today, thanks to the variety of pickups available and the options in woods and other components, it's not hard to set up a guitar that suits several styles well.
Within each pickup category, single coil or humbucker, there can be big differences; the number of turns of wire in the winding, the material used for the bobbin, and the type and shape of the magnets are key elements in sculpting a pickup's sound. Dual-coil pickups, or humbuckers, aside from having more or less winding and how the coils are connected to each other, in series or parallel, pick up twice the string length of a single-coil pickup; combined with a generally higher output, this gives them a fat sound richer in harmonics. Single-coil pickups pick up a narrower portion of the vibrating string length, so the sound is usually more defined and brighter than a humbucker's; this holds for traditional pickups, since today the market offers single-coil-format humbuckers, high-output single-coils with added metal baseplates, humbuckers that are a mix of two types of single-coil, and let's not forget we can modify the sound depending on how we configure the connection between pickups or between the coils of a single humbucker.
Many guitarists, with the idea of increasing sustain, replace their pickups with higher-output ones, which makes it easier to get a more compressed sound and saturate the amp's preamp. This changes the tone, but it isn't what makes the string vibrate longer. If we play the guitar in one room and have the amp in another, we'll see that the sound of the note played through the amp decays together with the vibration that note produces in the guitar's body; if, on the contrary, we play and hold a note with the amp in front of us, we'll see the sustain increase, because the sound produced by the speaker excites the string, keeping it vibrating longer thanks to the interaction between amp and guitar; so pickup output is not the most important factor in improving sustain. Pickup placement also determines tone. If you try playing a guitar unplugged, picking at different points between the end of the fretboard and the bridge, you'll hear the sound change, which gives us an idea of what the pickups are or aren't “hearing.”
Electronics
Active or passive. 250K or 500K pots, capacitors of different values and types; with all these options and differing opinions on the subject, it's hard to make a decision.
With traditional guitars or basses it's simpler, since certain configurations work best. But today there are guitars that use different types of pickups, so it's hard to decide which pots to use when we have single-coils and humbuckers on the same instrument. The rule to keep in mind is this: the higher the pot value, the brighter the sound, and the higher the capacitor value, the darker the sound when we turn the tone toward zero. It's wise to use pots suitable for volume or tone that are of at least minimal quality. The type of wire is also very important, since we won't get the same sound quality with cheap copper wire as with silver wire. If these two components are good, we're left to play with different capacitor values, since with an effective tone control we can better master this parameter. It's not unusual to see guitars with a good acoustic sound and quality pickups that then fall short in components and wiring work, so the result is an amplified sound that doesn't do them justice. Active electronics are used more on basses than on guitars, since basses seem to benefit more from their virtues; however, guitarists' ears are used to the sounds of guitars with passive electronics. Personally, I prefer good passive electronics for a guitar and active for a bass, of the best quality, mind you, since the active circuits used in the cheaper instruments don't exactly help bring out the best in the instrument.
In the next installment we'll talk about the finish, strings and how to evaluate a guitar when buying it and/or upgrading it. I recommend checking articles published in previous issues if you want more information on any particular aspect.