Techniques for Miking Vocals and Musical Instruments
by Richard Honeycutt
Once upon a time, I wanted very much to be a recording engineer. At the time, the only mic technique I knew was what I had read in early-1960’s Popular Electronics, Audio, and other magazines about picking up a small jazz group with a single mic or a single stereo pair. During high school, I had the opportunity to record my small dance band, learning quite a bit about miking, as well as how to (and how not to) direct-feed a guitar amp into a recording mixer. One of my best friends was employed in radio, and he taught me a lot. So it was that when I entered college, I became recording engineer for the 50,000-watt educational FM station on campus. My responsibilities involved recording regular performances of the Winston-Salem Symphony, many student vocal and instrumental recitals, and the first handbell choir I ever heard. Our mic complement included a Neumann U81, an RCA 44DX, a Western Electric 639B, a Shure 55, an Electro Voice 666, and several Electro Voice 664’s.
Although I took on additional jobs with the radio station as I progressed through college, I continued as recording engineer; in my junior year, I learned exactly how not to mic a trumpet: directly on-axis. About a year later, Doc Severinsen played at our university, and I saw how a trumpet should be miked.
Attending concerts over the years, I noticed that our industry goes through cycles of poor to OK to good to OK to poor mic technique, and I perceive that we are now sliding downhill on that cycle. As an example, I saw a university jazz band performance last week in which the faculty member who probably played some excellent flute solos could not be heard by the audience because of poor mic technique. In churches, worship leaders and singers with no concept of how to use a mic are legion. What we need to do is to help musicians and vocalists understand some principles of good miking, because the sound person does not ultimately have control over how a mic is used in performance. So what follows is a reminder for those of us who may be out of practice, and a reference that can be printed and used as a handout for musicians and speakers whose talks and performances we amplify, broadcast, or record. Mic choice is important, but is not the subject of this blog; instead, we’ll focus on how to use the mic for various sources.
If the mic is stand-mounted, it should be from 6” to a foot from the mouth(s) of the vocalist(s). A lot depends upon feedback margin in live sound, but for recording, closer is not necessarily better. The proximity effect of the mic must be considered, since even with a good mixer, proximity effect cannot be completely filtered out. If vocal groups are feeding more than one mic, the distance from each performer to the mic intended for him/her should be 1/3 or less of the distance to other nearby mics.
Handheld mics should preferably be at least 6” from the mouth, common practice notwithstanding. Even with excellent pop filters, p-popping can still be a problem with mics in the tonsil position, and the vocals will never sound as good with the mic too close. At the other end of the spectrum, as Garrison Keillor would remind us, shy persons should not place the mic at the belly button and expect it to do any good; they should just eat their Powdermilk Biscuits and hold the mic about 6” from their mouths.
As you may suspect from the common name of a generic brass instrument, they are acoustic horns. Thus they beam higher harmonics on axis, giving a harsh sound. The mic should be 15 to 30 degrees off-axis, and about a foot or two away from the bell. (See Figure 2.) Brass-winds such as saxophones should be miked like woodwinds such as clarinets.
Clarinets, saxes, sarrusophones, bassoons, bagpipes etc. radiate sound from pretty much the whole instrument, so the mic should be placed accordingly. Shoving it up the bell results in a “honky” sound. (See Figure 3.)
Flutes and Recorders
The sound of this class of instruments comes from the fipple, which is the place where the air turbulence is created near the player’s mouth. Miking at the far end of the instrument will accomplish little, as the aforementioned music faculty member did not know. (See Figure 4.)
The strongest sound from a guitar comes from the sound-hole, but the sound quality there is boomy and—in live sound—feedback-prone. Moving the mic toward the bridge improves the tonal balance, unless you get it too close to the bridge, where it may sound thin. Different guitars radiate sound somewhat differently, and some need the mic closer to the end of the fret-board, although overdoing this can result in a thin sound, or too much finger noise. (See Figure 5.)
Violins and Violas
These instruments radiate sound mainly from the f-holes and the top plate. But miking over the top plate gives a strident sound. Better to mic an about head level of the player, about 2-3 feet away, for a good frequency balance. (See Figure 6.)
You can mic a string bass in front of the top plate, below the bridge, but a common technique that works well for live sound is to wrap a mic having good vibration isolation in foam and wedge it gently between the tailpiece and the top of the instrument. (See Figure 7.)
Even in these days when the norm for amateur audio recording is using a smart phone with its built-in mic, it is possible to get good sound if you use decent mics, properly placed! rh
Richard A. Honeycutt developed an interest in acoustics and electronics while in elementary school. He assisted with film projection, PA system operation, and audio recording throughout middle and high school. He has been an active holder of the First Class Commercial FCC Radiotelephone license since 1969, and graduated with a BS in Physics from Wake Forest University in 1970, after serving as Student Engineer and Student Station Manager at 50-kW WFDD-FM. His career includes writing engineering and maintenance documents for the Bell Telephone System, operating a loudspeaker manufacture company, teaching Electronics Engineering Technology at the college level, designing and installing audio and video systems, and consulting in acoustics and audio/video design. He earned his Ph.D. in Electroacoustics from the Union Institute in 2004. He is known worldwide as a writer on electronics, acoustics, and philosophy. His two most recent books are Acoustics in Performance and The State of Hollow-State Audio, both published by Elektor.