Guitar Electronics

Guitar Electronics as the Key to Ultimate Happiness- Road Dog- Spring ’01

It’s mid-December as I begin this column. The touring season has wound down, and I’m not due to hit the road until the second week of January. I have a brand new Signature Model guitar which sounds great, the Christmas shopping is done and tree is trimmed, the faithful hound is by my side, and I should be lying on the couch eating bonbons and taking it easy. Guess what I’m doing instead?

I’m working on my guitar sound. Every day, for at least a few hours, I’m plugging in and working on improving both my gear and my understanding of it. I’ve used the arrival of the CPSM, with its revolutionary pickup system, as a reason to re-examine my entire signal chain, from guitar through cord, preamp, mixer, effects devices, and on to the amplifier and speakers at the other end of the chain. So far I’ve spent 40 or so hours and several hundred dollars replacing gear, testing cords, listening critically with headphones, and most importantly, auditioning the amplified results with my PA system over and over. I will probably continue this project for the entire month, until I have achieved the result I seek. I also anticipate that I’ll learn a bunch more from my first four or five concerts, and that the fine tuning will continue for months.

I’ve written thousands of words about guitar amplification for several publications, yet T. J. Baden’s relatively short article in the Fall 2000 Wood and Steel cut right to the heart of this matter and addressed the most important aspect of creating a quality amplified sound from your acoustic instrument- The performer must put in some time learning about the entire signal chain, from the guitar, through the pickup and preamp, through direct boxes, effects boxes, mixers and amplifiers, and back into monitor and house speakers, and make informed choices in each case, if he or she wants to end up with a quality product.

Please remember: an audience member at your performance doesn’t know how your guitar sounds acoustically. All he or she can possibly know is how it sounds as it comes through the speakers. This year I will perform before thousands of people. I don’t sing very often, so aside from the rare unamplified house concert the only sonic impression that my audiences will carry home from my performances is my amplified guitar sound. That fact alone makes it worth my time to put as much effort as necessary into the quest for great sound.

Also consider this: Your performance skills must include your being comfortable with every aspect of being on stage. This includes being physically comfortable in the performing environment, and it also means being at ease with your electronics so that using them in front of people becomes second nature. If you need to adjust volume, activate a notch filter, change EQ, set one guitar down and pick up another, and plug or unplug, you must be able to do these things in a professional, competent manner, getting great sound all the while, or your technical playing skills will be all for naught. Electric players have known for fifty years that they needed to learn about more than just their guitars, and have made a science of studying their pickups, amplifiers, cord lengths, impedance problems, effects devices, amp miking techniques, and even speaker and tube types. Acoustic players who perform are overdue in acquiring this same sort of knowledge. This deficit has led to a lot of spotty performances. Notice that I’m not suggesting that acoustic performers didn’t play their guitars well, but rather that the performances didn’t come across because the sound was faulty for one reason or another.

Perhaps people who gravitate to the sounds produced by great wooden instruments don’t take as easily to discussing mismatched resistance, ground loops, transducer pros and cons, or phase relationships between sound sources and speakers as they do to articulating the glorious sounds of the acoustic guitars that they play. Acoustic sound has too often been seen as the end of our search, when anyone who is serious about performing must realize that it is only the beginning. The philosophy professor who instructed me in formal logic would call a great-sounding acoustic guitar a “necessary but not sufficient condition,” to produce a great amplified tone. It’s very hard to make a bad-sounding acoustic sound even reasonably good through a sound system, but you can far-too-easily take a great sounding one and mangle its amplified sound to the point of rage and madness, both in yourself and your audience.

Don’t feel singled out here. I don’t mean to confine my comments on our collective shortcomings to us players alone. The musical instrument industry often furnishes us all with far more hype and marketing about this gear than solid information, and the guitar makers who are trying to satisfy our desires for perfect factory-installed setups are caught in the middle, having to choose between installing the existing products that are available or spending valuable resources doing research trying to innovate new electronics themselves. All in all, we are all becoming multi-disciplinary, with acoustic players having to learn about electronics, while the guitar makers either partner with the amplification industry or begin research themselves on the road towards the next generation of pickups, preamps and the rest of the signal chain.

In the meantime, we have to play out every day with today’s gear, so we need to understand this stuff better than most of us now do. Those players who are are aspiring performers, or just starting out in the world of amplification and performance can graze the contents of this article and save it as a resource for the future. Those who are already semi-regulars in their home town venues should treat this content as an electronic buffet from which to draw information as needed, while those of you with established performance histories should plan on absorbing the whole enchilada thing over the next few months.

Here are some of the major topics which you’ll need to address as you bring your electronics IQ up to par with your acoustic skills:

Electronics 101– Do you know what impedance is? Do you know the difference between line level and mic level signals? Do you have the information at hand to decide whether it makes more sense to add effects to your guitar with an effects send and return or by plugging your guitar directly into a stomp box? Do you understand what phase relationships are, both electronically (as pickups and speakers are wired in or out-of-phase) and acoustically (as being in or out-of-phase can greatly affect your sound in real rooms with real speakers, with back walls and reflections, with your choice of performing locations and so on)? Do you know how effects boxes can take your mono input signal and produce a stereo output? Can you explain in 30 words or less how you might configure a parametric EQ so that it can notch out a feedback point in the bass response of your guitar without trashing the guitar’s entire low end response? Do you know about the relationships between frequency and wavelength, and have you ever heard of a standing wave or heard one affect your live sound? Do you know how to add or subtract low-end response from your sound by your performance position and that of your speakers in any given venue? Do you have a strategy for preventing ground loops at all of the poorly-wired venues that you’re bound to visit in your journeys? Do you know how to handle subwoofers, and how you might adjust them and their crossover points when they are giving you too little or too much bass? Can you operate graphic equalizers, reverb units, chorus devices and sonic maximizers with some semblance of professionalism?

Pickups– A common engineer’s mantra is to blow 80% of your money on the transducers, the parts of your signal chain that convert energy from one form to another. Pickups are but a form of transducer, as they take the mechanical vibrations coming from your guitar strings, its wooden parts, and from the air around it and convert those mechanical vibrations into electrical signals. There are four basic kinds of pickups with which to approach your acoustic guitar’s amplified sound: microphones, saddle-mounted transducers, stick-on transducers, and magnetic pickups. Do you know the basic characteristics of each of these, how it works, how and where it is commonly mounted, its electronic peculiarities, and its strengths and weaknesses? Take your time here- this choice is the most important amplification step that you will take. You might consider pickups as providing you with partial snapshots of your guitar’s acoustic sound, with each type of pickup being good at conveying part, but not necessarily all, of the picture that you seek. Your technique will influence your choice, so the overall idea is to team your technique, your pickup choice(s) and your guitar with the sonic results that you’re hoping to achieve.

Here’s an example: I don’t play a big, loud guitar, I play relatively fluidly and lightly, and I use slide, tapping and the E-bow from time to time. Experience has led me to recognize that a dual system with substantial reliance on a magnetic pickup works well for people like me, provided I can EQ my two sources separately. Thus the new Chris Proctor Signature Model boasts the first stereo Prefix system and a custom Rare Earth magnetic pickup as part of the package. I then carry outboard gear to sculpt the sound as needed, and to deliver it to the house system in any form that they might require. On the other hand, a flatpicker’s dreadnought might sport a Matrix/microphone blend, because that guitar’s louder voice and the player’s flatpick attack might be best rendered with a saddle pickup and garnished with some moving air from the microphone. There are lots of possibilities, and exploring them all will be your most important priority as you learn about guitar sound. This crucial search should take precedence over proceeding to the rest of the information in this article.

Cords– Buy the best and shortest cord that meets your needs to get your signal from the guitar to the next part of your signal chain. This is not the place to save money- your signal is at its most vulnerable before it gets boosted to line level by a mixer or AC- powered preamp, so spend the money and thank me later.

Preamps– These come in four basic forms, Onboard, in-line, AC-powered separate preamps and those that are incorporated into the front ends of mixers, guitar amplifiers and so on. The former two are usually battery powered, and the signal that they provide is still in need of boosting before it heads down the line towards effects and amplifiers, while the latter two produce a true line-level signal that is ready to send to effects units and drive a power amp. Many folks use both battery-powered onboard preamps and rack type, wanting the best of both worlds.

Mixers– These integrate preamps with other functions so that you can add effects, shape the individual and overall EQ’s, add vocals or other instruments, and send a final signal to an amplifier. Think of them as you might think of a stereo receiver in your home stereo, which takes signals from CD players, FM or AM tuners, Video inputs, and even turntables (remember them?) and gives you general controls over the resulting mix.

Effects– Reverb, chorus, delay, and so on are all common elements for acoustic players these days, and these come in stomp box form, meaning that your guitar plugs directly in and out of them as it heads towards the preamp stage, and in AC or rack form, where a portion of your preamped line-level signal is sent from your mixer or guitar amp into the device and returned to you for adding wet, or effected, signal to the unaffected signal as you choose. Make sure you understand what these effects are, how they are produced, the basic parameters of each, and how to make sensible adjustments to them during the sound check and on the fly. For reverb, you’ll need to learn about hall, room and plate programs, about the decay time of the program you choose, the amount of pre delay it has, and what kind of EQ you might choose to shape the reverberant sound to your liking. With chorus, the operative parameters affecting its sound are its rate, depth and resonance, and with delay it’s primarily deciding how long the echo waits to appear, how many times it comes back, and how much of it you want in the mix.

Amplifiers– Power amps are what I’m talking about here, not guitar amps, which package several of the items from my list into portable packages. Power amps accept line level signals from preamps or mixers and drive your speakers. As long as you have sufficient power to meet your speakers’ needs, have the correct impedance match between amp and speakers, and you can lift it without damaging your lumbar region, you should be fine here.

Speakers– These are as crucial at the final end of the signal chain as the pickups were on the front end of things. Remember the engineers’ mantra- you should spend your time and your money on the transducers in your signal chain, and speakers, as transducers, take the amplified electrical signal from your amp and change it back to mechanical sound wave energy so that your audience is stunned by the clarity and beauty of your guitar sound, and so that you can forget about your sound and concentrate on your technique and your performance. That is the point of spending time and money on speakers, on learning to position and use them, and of course, on the pursuit of a great amplified guitar tone in general.

Sound Techs– These are the guys and gals who can make or break your show, and they are your partners each evening in your amplification quest. They know more than you do about just about everything we’ve discussed, and thus they will be interested in finding out how fluent you are in electronic conversation. Your knowledge of your gear will either impress or depress them, and can either make them happy to please you or on guard and alert. Basics? Know what sort of signal you’re sending them; line level or mic level, high or low impedance, stereo or mono. If you need AC power, ask them for the best clean unswitched source. Know your gear. Know how to avoid obvious mistakes, like not checking with them to see if their board is safely muted before you power up your gear, or starting out with hot level settings as you begin to do your check.

In Summary– I hope that you can see that we have set out to accomplish two main tasks with these articles; first to learn about all of this electronics stuff, and second to put that knowledge to practical use and experimentation- to make our guitars sound great when plugged in. You can find lots of ways to get this knowledge- music stores, more experienced performers, books and videos, workshops like ones we offer at Taylor dealers, friendly sound techs who don’t mind sharing some of their hard-won knowledge, and so on. Here are some tips for putting your knowledge to work once you feel ready. Set up a complete system somewhere in your house and leave it up for days or weeks if possible. Use it to play a dry run/dress rehearsal through a complete set or two, use it to try out all of your performance moves multiple times, all your changes of tunings, guitars, effects EQ, and level changes, your vocal and instrumental pieces, and so on, and fine tune all of your physical moves and electronic settings over this period of days or weeks. If you are so lucky as to get a sound check in an empty house before any of your performances, ask for an early check, ask the sound man if he would leave the system up and running after your official check is done, and use the time that you now have before the house opens to try everything under the sun again, listening carefully do the differences that you observe between your home experiments and your current amplified space. Each room sounds different, each set of speakers, each volume change and each performing position you assume on stage, and the more real-world experimental data that you have under your belt the more comfortable you will be with the use of your gear.