Since we talk about shielding electric guitars so much at Humbucker Soup, it’s very common for us to get questions about acoustic guitars and whether or not they need to be shielded from RF and electromagnetic fields as well. Join us now while we take a look at acoustic guitar shielding and what methods, if any, you might use to accomplish it.
Acoustic Guitar Shielding: Interference
An acoustic guitar is a natural device that does not pick up and output static created by nearby electrical devices. Since it merely amplifies the sound of a plucked string, there is no need for acoustic guitar shielding. However, finding some method of amplifying the guitar so it can be better heard has produced many types of acoustic pickups that do pick up interference.
The most common way to amplify an acoustic guitar is by using a microphone. The best approach to acoustic guitar shielding, if a microphone is being used, is with a standard XLR microphone cable. These are the types of cables that have three prongs on each end.
In some cases, you may want to mic your guitar and plug the microphone into a nearby amp that does not have an XLR input. When you want to plug a mic directly into an amplifier, the best way to shield this connection is to use an impedance transformer. An impedance transformer will allow you to use the XLR cable to cover the majority of the distance. The impedance transformer plugs directly into the amp, minimizing exposed cable.
Soundhole pickups have been around for quite a while. This acoustic amplification device is a portable single-coil pickup that fits into the soundhole. It has a long cable that you can plug into an amplifier or mixing board. Unfortunately, this kind of pickup is prone to noise, just like a Fender Stratocaster or any other guitar that uses single-coil pickups.
There is not much you can do to shield this type of pickup, because of its nature. If you are handy with electronics, and it’s noisy enough, you might try coating the outside of the pickup with conductive paint and soldering a wire from it to the ground of the pickup cable. However, this will probably look bad and it might change the tone. Also, it may not reduce the noise much. Single coil noise is the reason guitar builders invented humbuckers. There are a few brands of humbucker soundhole pickups, but they are much less common.
Electric acoustic guitars are the type that has output jacks on the guitar itself. You usually cannot see the pickup, and it can be one of various kinds. The most common type is a small piezo microphone. These guitars often have an onboard system that may let you turn the guitar on and off. You might also be able to adjust the eq and volume. Some systems even feature a built-in tuner. This style of pickup contains a preamp that’s very advanced and usually doesn’t require any additional shielding on your part. If you notice a lot of noise while using your electric acoustic guitar, it could be that the battery is low or the preamp is malfunctioning. You will need to seek out an experienced technician to deal with a malfunctioning preamp, and it will usually need replacing instead of fixing.
We hope that you have enjoyed this quick look at the different ways of looking at acoustic guitar shielding. If you are playing at home, we recommend a microphone using an XLR cable into the mixing board. If you are performing live, we recommend an electric acoustic as this type of pickup sounds better and was shielded at the factory. We would only use soundhole pickups in a pinch, or because we wanted to run the guitar signal through some effects pedals.
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