Singing Live with Acoustic Guitar
Getting the most out of your mic setup.
One of the most straightforward forms of live performance involves singing while accompanying yourself with acoustic guitar. In fact, it's amazing what some performers can do with this simple setup! Since many singers write their songs with guitar, it's no surprise that great things emerge. Once you've written your songs, practiced them to perfection, and gotten over your stage fright, the next issue becomes how to sound your best on the stage.
Pitfalls of Performing
Even though this type of performance would seem to be technically simple to deal with in terms of microphones and PA systems, the truth is that with such a pure form, any flaws are easily heard. Often, your audience is made up of fans, friends and relatives that know your voice and expect to hear it without any problems. More than this, the human ear is most sensitive to the vocal range and will detect distortion or changes in tone very readily.
First, watch out for phase problems. If you've ever heard a "hollow" sound that seems to change in character when the performer moves around a little bit, you're hearing a phase problem. This occurs when you are using more than one microphone, and those microphones are not right next to each other. The sound takes time to travel, and therefore arrives at the two mics at slightly different times. For example, the sound from your voice reaches the vocal mic first, then goes another one or two feet to the guitar mic a fraction of a second later. This may not seem like a lot of time but in terms of sound waves, these two differently timed versions of the same signal do not mix well. Due to the complex interaction of the similar waves, some of your sound is cancelled out.
"You'll learn what really works by trying it out on stage, at the coffee house, or wherever you perform." There are two solutions to this issue. First, try using only one microphone. Legions of bluegrass performers have discovered this solution and use it in performance every day. The keys are to a) finding a microphone that sounds good on both your voice and your guitar, and b) find the best position to capture both accurately. The biggest problem with this approach is that you may need to place the mic some distance away, making it more difficult to get enough gain before creating feedback in the PA system. Also, you'll most likely want to use a condenser microphone to get enough detail out of both the voice and the guitar, and condenser mics are often more expensive than dynamic mics.
One last issue is that mics designed for vocal performance are tailored for very close use. When they are used at a greater distance, such as for voice and acoustic guitar, often they will sound "thin". Because of this, a mic designed for use in the studio where instruments and voices are usually a bit further away, may be the best choice. Studio mics are usually a lot more sensitive than those designed for live performance, so if you go this route, you'll have to put extra effort into avoiding feedback.
Using Two Microphones
Most often, singers who accompany themselves with acoustic guitar will use a dedicated microphone for both voice and instrument. By doing this, you are able to get each mic closer to the sound source, thereby reducing the chance of feedback. Also, you can use an appropriate mic for each position. Most singers today are using dynamic handheld mics for vocal performance. These mics are readily available from a number of good manufacturers, can sound very good, and are relatively inexpensive. To achieve better results, consider one of the more recent handheld vocal condenser mics. They cost more, but will provide a greater degree of nuance and expression in performance.
For the acoustic guitar, most often a small diaphragm condenser mic is used, due to the greater sensitivity and excellent high-frequency response that this design provides. There are many models to choose from, and generally, the more expensive ones will provide more detail, nuance, and also bring out the "character" of the guitar.
However, using microphones with acoustic guitars in live performance can be a challenge. The combination of a sensitive microphone with an instrument that does not have a very loud acoustic output means greater gain is required on this mic than on the vocal. Thus, feedback is always a concern.
To work towards solving this problem, and also to help with the phase issue mentioned at the beginning of this article, it is wise to choose mics for the stage that have very tight polar patterns. The best choices for voice are cardioid, supercardioid and hypercardioid. (See the last issue of Singer for details on these patterns.) For acoustic guitar, hypercardioid is probably the best choice. By pointing the null (dead side) of this mic towards the vocalist, and getting the mic close to the guitar, you should be able to get enough gain and not pick up too much vocal.
Since many of us perform outside during the late spring, summer and autumn months, it's important to know some of the methods for dealing with wind noise. The most common solution is to add a foam windscreen to any mics that are on stage. Windscreens are inexpensive and readily available, and are fairly effective at reducing the rumbling from wind interference. The only drawback is that foam windscreens do absorb some of the high frequencies from your voice and guitar. If you find the loss objectionable, a little EQ at the mixing board (perhaps adding +3dB at 12kHz) can help. If you find that the windscreens are not effective enough, due to very sensitive microphones or excessively high winds, one trick is to cut a 6" circle out of nylon hosiery and rubber band it over the windscreen. This should add an additional bit of protection. Some manufacturers actually make "extra large" windscreens for high wind environments-also a good solution. One final step is to reduce the low frequency content at the mixing board by "cutting" everything below about 70Hz. Since there is no vocal or guitar sound below this frequency, all you are removing is the rumble from the wind.
Go Forth and Perform!
The best way to find a working solution for using microphones when performing live is to go out and do it. First, test your setup in rehearsal to work out the major issues. Then, you'll learn what really works by trying it out on stage, at the coffee house, or wherever you perform. After a few gigs, you'll know exactly the best way to set up your mics and get the best sound with no phase problems, feedback, or wind noise. Break a leg!