Buyers' Guide to Acoustic Guitar Pickups
Choosing which acoustic pickup to buy can appear almost as daunting as buying your guitar. There seems to be a huge range on offer and deciphering which one is the right one for you and your needs can seem like a minefield. Depending on what you need, you can go as simple or as complex as you please. Opting for a system with more features can mean you pay that bit extra, however, that doesn’t mean that you have to pay the earth to amplify the sound of your acoustic instrument. Some people simply want to be heard a bit more, particularly if you are playing in a band and competing with other instruments. Whereas other players want the flexibility to explore and shape every corner of their tone. Either way, there is no ‘correct’ way of amplifying your acoustic sound, but being conscious of how each pickup operates and how it will dictate your amplified sound should make your choice a lot less baffling.
Below, we’re going to outline the main differences between the various types on offer and how they achieve their sound.
The various types of acoustic pickup available will usually fall into a few main categories; magnetic, under saddle transducer/soundboard transducer and microphone or sometimes a combination of two (or more of these).
Each type of pickup has its own tonal characteristics and features so it’s important to bear in mind different pickups will be suited to different playing situations and styles so well worth exploring and trying (where possible!) all the options open to you.
In essence, when amplifying an acoustic guitar, you’re looking to capture the natural sound of your instrument as best as you can. The purest way you can capture your guitars true sound would be to place a microphone in front of the strings. With a good quality condenser microphone, you’ll essentially be hearing what you would normally hear, only louder. Great! Sounds like a winner, why not just do that then? Well some people certainly do and with fantastic results, particularly when recording. However, whilst there are clear advantages, mic’ing up your acoustic instrument certainly can have its pitfalls. Maintaining an even output of sound is really all about staying in a relatively still position. As we know, guitar playing is emotional, and no matter how wooden or rigid we may think we are when playing, we all move to some extent and if the guitar is moving around in front from a sensitive microphone it could result in unevenness of sound. Mic’ing up an acoustic guitar can be fraught with feedback issues too, particularly if you are playing at higher volumes, not to mention they can also pickup other instruments or surrounding noises too.
Under Saddle Transducer (UST)
Under Saddle Transducer type pickups are the main type of pickup you will find pre-fitted on acoustic guitars in the shops today. They consist of small individual piezo electrical crystals aligned and connected along a thin strip which sits underneath the bridge saddle of your guitar. As the strings are played, their vibrations create downward pressure on the saddle and then onto the transducer. The crystals within the transducer convert this energy into an electrical signal. Some transducers will be made with a ribbon of piezo film as opposed to individual crystals. The advantage of such design means that the positioning of the pickup underneath the saddle needn’t be as exact as those pickups with individual crystals, and as a result can offer better string to string balance.
Transducers can come in both passive and active forms. As mentioned above, a passive pickup is one that’s signal is transmitted directly into the amplifier and does not use power (via a battery source) to control the sound.
On the flip side, an active pickup is a pickup that uses electronics powered by a battery to control the sound. Many pickups that produce a low signal will utilise a preamp (powered by a battery) to help boost the output and help shape the sound. These preamps can be fitted to the guitar itself or can be external. Because of the added power, active pickups do tend to be brighter and louder too.
Unless you are proficient in fitting these kind of systems yourself, it’s always recommended that a transducer type pickup is fitted by an experienced luthier in order to ensure it is fitted correctly. An incorrectly fitted transducer can mean you simply don’t get the most from it. There is an element of drilling with this type of pickup too but whilst the installation process can appear more intrusive than the magnetic counterparts, once they have been installed, they are pretty much hidden from view so aesthetically they may be more appealing than a magnetic pickup.
Piezo type pickups are an ideal choice for players who play in bands with a whole host of other instruments. Sonically, they are able to cut through the mix very well and generally function well at higher volumes so don’t suffer too much from feedback issues. Whilst UST do have obvious advantages, they do only really pick up the sound of the strings and as a result don’t always reflect the true character of the guitar. With this in mind, some people consider the sound to appear a little more ‘processed’ and ‘artificial’ in comparison to the other pickup options. You may have heard people refer to this as a ‘piezo-quack’ which can produce undesirable overtones.
Soundboard Transducers (often referred to as contact pickups)
Soundboard transducers work in a similar fashion to piezo under saddle transducers, however, they are mounted to the underside of the soundboard (or top) or underneath the bridge. These pickups ‘feel’ the vibrations of the soundboard or bridge, depending on whereabouts they are mounted. As a result, they are feeling the vibrations of the guitar itself as opposed to the strings and replicate a sound more akin to the guitars natural acoustic tone.
One of the disadvantages of a soundboard transducer is that they can be quite microphonic and as a result can have feedback issues if used at higher volumes. In addition, a guitar’s top will have hotspots as well as deadspots too (areas that create a good amount of vibrations and vice-versa). As a result, if these pickups are mounted to the underside of the body, it can be difficult to decipher the best place to stick the contacts.
Preamps are used for several reasons and using one can offer various benefits apart from simply boosting a pickups signal. Depending on which type of preamp you choose, they can have the ability to improve the sound quality if you are having any issues with balance or crackling etc. They can also help you shape the sound with EQ controls, help reduce feedback and also allow you to blend the sound of multiple pickups together if you are using a blend system (see below).
A pre-amp can come in many forms too from basic to more complex. You may have seen some guitars fitted with what is called an ‘onboard’ preamp system. This is the box of controls that you see on the top side of some acoustic guitars and they usually have a few handy extra features that go further than just volume and tone knobs. Depending on the complexity of the system, some will have more features than others. For instance some may have parametric EQ’s allowing you to control different frequencies other than simply ‘tone.’ This is particularly handy if you find feedback is coming from one particular frequency. The addition of an on-board tuner is often a nice extra, plus many will have a phase button which inverts the phasing and this helps combat feedback.
A simpler type of preamp is having one that is built into your endpin jack socket. These are great if you didn’t want to use a sidemounted preamp system which does require you to rout out a section in the side of the guitar (understandably, this is not always the most desirable thing for some people). This preamp can be paired with something as simple as a couple of thumb wheel controls that sit just inside the soundhole of your guitar to adjust volume and tone levels. This no fuss option may be more appealing for players whereas a sidemounted eq system could appear overkill.
External preamps are a third option. These usually come in the form of a floor pedal and offer very similar features to that of a sidemounted onboard EQ system, and more in some cases. These are great if you didn’t want to have a pre-amp built into the guitar or if you wanted something that offers you greater flexibilty in adjusting more intricate parameters of your sound.
As we’ve seen, each pickup system works slightly different from one another and as a result each has its own benefits and limitations. With this in mind, manufacturers have produced blend systems that incorporate a combination of two (or more) of the various systems in a bid on capitalising on the benefits of each to help give the best tonal qualities possible.
These systems often incorporate a condenser microphone of some description to help give a fuller sound and contribute to a more natural tone. Versatility is probably their greatest asset. By having multiple pickup options you can blend them to whichever balance of each pickup you desire. Some situations will call for one pickup to be solely engaged, whereas another situation will allow you to use the other or both of them in combination with each other. Whilst these systems offer greater tonal options, they do come at a price and typically they tend to be the more expensive pickup systems on the market.