What Are Acoustic Guitar Pickups?
Much like an electric guitar, an acoustic guitar pickup takes the sound of your acoustic guitar and converts it into a signal that can be amplified. Converting and amplifying an acoustic guitar tone as, unlike an electric guitar, an acoustic guitar has a rich and dynamic unplugged tone where the resonance of the guitar itself plays a big role.There are three main types of acoustic guitar pickup, Magnetic, Piezo, and Microphone all with their own distinct character and method of picking up sound.
Why Do I Need An Acoustic Guitar Pickup?
Acoustic guitars are pretty loud by themselves, but if you're going to be playing live in bigger venues, you're going to need to amplify your guitar. You could set up a mic in front of your soundhole, but it's far more convenient to use a pickup, especially if you want to incorporate acoustic guitar effects into your sound.
How Does a Magnetic Soundhole Pickup Work?
A magnetic soundhole pickup works by wrapping an insulated copper wire around around a magnet, creating a magnetic field which is ‘disturbed’ by the vibration of a steel guitar string. This is identical to an electric guitar pickup.
What Does a Magnetic Soundhole Pickup Sound Like?
Magnetic soundhole pickups have a warm and musical tone, with good string detail. Due to their construction, magnetic soundhole pickups have a sound that shares characteristics with an electric guitar pickup.
Soundhole pickups are a great option as they provide great sonic warmth in comparison to a Piezo pickup, they're easy to control and they interact well with effects. There's also the added benefit of an easy installation as you generally just have to drop them in and tighten a couple screws to fasten!
The problem with a soundhole pickup is that it doesn't capture the acoustic resonances inside the body itself. Your guitar will still sound like an acoustic but it won't have the complexity and resonance of its unplugged tone. A drawback of using a magnetic pickup on an acoustic guitar is that it can be prone to feedback which will need to be managed. Additioanlly, magnetic soundhole pickups don't work with nylon-strung acoustic guitars.
How Hard Are They to Install?
Magnetic soundhole pickups are really easy to install and can be fitted without making any permanent modifications to your guitar. Most models simply fit onto your soundhole and then you just turn a couple of screws to tighten and plug it in. Fitting it this way will result in a cable hanging out of the soundhole, if you want to hide it you may need to make some more significant mods.
How Do Piezo and Transducer Pickups Work?
Transducer pickups work by converting physical vibrations into an electrical signal which can then be amplified. The most common type of transducer is the Piezo system which sits between the bridge saddle and the bridge itself with vibrations from the string causing changes in pressure, changing the voltage of piezoelectric material. Other transducer pickups attach several transducer heads under the body top (soundboard) to pick up vibrations.
What Do Piezo and Transducer Pickups Sound Like?
As transducer pickups convert physical vibrations into an electrical signal they won't pick up the body's resonance or any ambient sound. The result is a more direct sound with a strong attack and a distinctive 'quack' to tone. A Piezo pickup has quite a bright and articulate sound as it picks up the vibrations of the saddle right under the strings whereas a transducer that goes under the soundboard will have a warmer tone with less definition.
Transducer and Piezo systems are more reliable than a soundhole pickup as their tone is easier to control and they aren't prone to feedback. A transducer or Piezo pickup is a great option if you want to amplify a nylon string acoustic guitar as they work by detecting physical vibrations rather than creating a magnetic field.
The sound of transducer and Piezo pickups can be considered a bit brittle or unnatural, especially with that characteristic 'piezo-quack' but that can be managed. Fitting a Piezo can also be difficult so you may want to buy a guitar with one pre-fitted or get a professional to do it for you.
How Hard Are They to Install?
If you're using an under-soundboard transducer you might find the installation a bit fiddly and you may need to drill a wider endpin hole to fit a jack. Installing a Piezo pickup is more difficult as it needs to be fitted between the saddle and the bridge. You can try fitting a Piezo system if you're confident working with tools and guitars, otherwise it might be best to take your guitar to a trained luthier.
How Do Internal Microphones Work?
An internal microphone is exactly what it sounds like - a small microphone placed inside the body of the acoustic guitar which picks up sound the same way your average microphone would.
What Do Internal Microphones Sound Like?
An internal microphone will have the most natural tone, picking up more of the resonances and percussiveness of your instrument and playing.
Internal microphones provide a more realistic recreation of your natural acoustic tone than magnetic soundhole or transducer/Piezo systems.
Microphones can be prone to feedback and your mic placement can have a significant impact on your sound. Internal microphones aren't very strong by themselves which is why you often see them come paired with another type of pickup like a soundhole or Piezo.
How Hard Are They to Install?
Internal microphones frequently come paired with Piezo systems and therefore will require a good level of knowledge for you to fit them yourself.
Combining Pickup Types
Many players find that they get the best results by combining different types of pickup, taking advantage of the particular strengths of each. For instance, many players like to use an internal microphone to capture the resonance and sonic depth of the guitar’s body, with a piezo system used to capture the detail and attack. Or, if the piezo sound is too up-front for that guitarists’ particular musical goals, a magnetic pickup and a microphone will give you a very full, round, ‘big,’ natural sound with good detail.
Most players don’t blend piezo and magnetic pickups, because both methods are driven by the strings themselves, so you risk the possibility of clashing frequencies and all sorts of sonic weirdness. So in short, if you want to blend, you'll be using a microphone pickup blended with something else - the question you need to ask is 'why?'
If your style is more rhythmic, a piezo & mic combination will give you a great representation of your guitar’s attack. If it’s more detail-oriented, a magnetic & mic combination will be more representative of what happens to the string throughout the whole life of the note.
There are some piezo pickups (such as the K&K Sound Pure Mini) which are placed on the underside of the guitar top, giving it a much smoother voice than a regular under-saddle piezo. Seymour Duncan’s Mag Mic combines a hum-cancelling magnetic pickup with an omni-directional condenser mic in one unit.
Acoustic Guitar Preamps
The majority of pickups (and some mic systems too) come with a preamp to further shape the sound. You'll often see small control panels on the sides or tops of the guitars. These most commonly feature a volume control and some kind of tone shaping. This can take the form of a simple ‘tone’ control, or perhaps individual knobs for different EQ options. You might also find a tuner built-in, often chromatic, meaning you can easily tune your guitar to alternative tunings.
If your guitar doesn’t have a preamp, that’s often a good sign that it’s a very transparent-sounding unit, and it’ll usually sound great plugged into any acoustic amplifier, DI / mixing desk or a preamp pedal. On the other hand, a decent preamp can often be the difference between an average acoustic sound and a great one. Sire's R3 and R7 guitars feature carefully engineered pickup and preamp systems aimed to provide beautiful tones at affordable prices. Their Zebra SIB system ('simple is best') combines piezo and microphone pickups with a simple built-in 3-control preamp. Their Zebra 7 system uses a similar combo of pickup types but also provides you with a detachable preamp at no additional cost, giving you unprecedented control over your tone. Read more about Sire's acoustic preamps here.
There are many pedal-based units out there and they give you a lot of freedom because you can choose exactly what you’re filtering your guitar sound through. Fishman offers a number of different Aura models in stomp box form, and the D-Tar Mama Bear has more of a ‘desktop’ design. This unit digitally filters your guitar to neutralise the sound of the pickup, then lets you dial in one of 16 ‘target instruments’ from parlours to super-jumbos.
(below) Sire's Zebra 7 soundhole pickup and outboard preamp.
Reducing feedback from acoustic pickups
Ah feedback, the common enemy of live musicians, public speakers and studio engineers alike. Feedback occurs when a microphone 'hears' itself through a speaker or output source, completing a sort of 'loop' in the sound - this causes the signal to increase in size, generating unattractive frequencies!
The same thing can occur with acoustic guitars - the pickup or mic system hears its own signal feeding back and creates a lot of unwanted noise. There are a few useful ways of preventing acoustic guitar feedback:
- Phase Switching - feedback is made worse by the fact that the phase (shape of the waveform) of the signal (in this case, your acoustic) going into the mic matches the one that's feeding back into it, causing that ugly loop we were talking about. A phase switcher inverts the phase of your acoustic so that it no longer matches the signal coming out of the speaker. This reduces the chance of the signals clashing and causing unwanted noise. Phase switches can be found in some acoustic preamps or acoustic pedals, such as the LR Baggs Para Acoustic DI Box.
- Soundhole Cover - this does exactly what is says on the tin. It's a simple piece of (usually) plastic or wood that sits over your guitar's soundhole, preventing the sound of your strings going into the body of the guitar. This can prevent any sound from looping back into the pickup system, but as you may have already guessed, it can change the way your guitar sounds, particularly if you're using a mic system!
- EQ Adjustment - sometimes the simplest solution is the best! In some cases, you can isolate feedback to a particular frequency - for example, a common issue with acoustics is feedback in the low-mid frequencies. This means a full-bodied, intrusive rumble coming out of your speakers - to combat this, try tweaking the EQ of your guitar. This can either be done on the guitar itself using the built-in preamp (if you have one) or on a mixer / sound-desk / EQ pedal. Reducing these frequencies can reduce the chance of boomy feedback!
Well there we have it, folks! The aim of this guide was to inform you of the different types of acoustic pickups available on the market today, and the advantages and disadvantages of each one!
Will you be performing live? Do you want a DIY project? Are you on a budget? Hopefully this article has answered all of your questions and taken you one step closer to finding the right acoustic pickup system for you!
While you're at it, why not check out the rest of our buyer's guides? You might just find something else you like!