As time goes by, I’m seeing more and more people trying to resolve audio problems by immediately turning to technology for the solution. I hear it in conversations and see it in the online forums and social media again and again — “what plug-in would you recommend to fix this <insert problem here>?” And to be fair, some incredible new technology has emerged, capable indeed of resolving various maladies. But quite a number of these are Band-Aids — and in some cases, the Band-Aid creates audio artifacts and other difficulties. And in many cases, the problems could be solved at the source through proper physical and acoustical practices.
In this month’s installment of Sound Sanctuary, let’s look at one such challenge: proper microphone technique. Improper microphone technique causes quite a number of headaches, and while we might be tempted to try to resolve them with signal processing, it’s far better to simply nip them in the bud and not allow them to happen in the first place.
The Polar Express
Every microphone exhibits a polar response pattern, of course, and we rely on these patterns to behave as expected. A cardioid should act like a cardioid and an omni should act like an omni. If they don’t, we may get unexpected (and unwanted) results. Most handheld cardioid mics achieve directionality by way of ports behind the capsule that facilitate the ingress of sound at a phase angle that differs from the sound entering the front of the mic. The phase cancellation between the two results in the mic presenting much more of the front input than the rear, making it directional. This physical phase-shift network is designed into the microphone and enables us to deploy the mic with confidence that it will pick up sound primarily from the direction in which we point it. I probably don’t need to tell you that this is important by way of avoiding feedback — which happens when our mic captures sound from a speaker that it’s also feeding. Mic directionality is also an important means of avoiding excessive spill. We’re known to point mics in very specific directions to not only pick up what we want, but to avoid picking up what we don’t want.
Cupping
Holding a handheld microphone the wrong way can drastically alter its polar pickup pattern. A significant number of vocalists hold their directional microphone in the wrong way. Specifically, they hold the mic in such a way as to cover the ports behind the capsule, which can largely render the mic omnidirectional, or at least diminish its directionality. At best, we only suffer unnecessary spill from sources other than the vocalist’s voice — drums, other vocalists, and perhaps on-stage guitar amps. At worst, the formerly cardioid mic’s new omnidirectional pattern creates a path for feedback.
Another issue caused by improper mic handling is a radical change in frequency response. Wrapping one’s hand around the capsule end of the thing will typically result in a substantial boost in the high mids — centered around 2 kHz. If monitors are rung out for this frequency, the boost may be enough to overcome the corrective equalization, and feedback may ensue. At the very least, it’s simply not going to sound good. Bottom line, we want to carefully and deliberately instruct everyone who ever uses a handheld mic on our platform that they must hold the mic by its “handle” — and never allow their hands to come near the grille of the mic — in fact, a gap of at least a half an inch from the grille is necessary.
Don’t Sing So Close to Me
We’re all familiar with proximity effect — moving the mic in extreme close proximity to the mouth tends to exaggerate low frequencies. I used to leverage this phenomenon during my early broadcasting days to boost up my less-than-adequate “radio pipes.” We’ve all heard stand-up comedians use the technique as well — creating a completely different voice to help create one-person dialogs. While the technique is useful and appropriate for speakers, it is not helpful for singers, particularly because its deployment is usually inconsistent. If we nail down a pleasant equalization curve for a singer, having them override it by punching up the bass with proximity effect is unhelpful and destructive to our efforts. This is every bit as bad as boosting high mids by wrapping a hand around the mic’s grille.
One other major issue relating to microphone technique is dynamic level. We jump through hoops to arrive at consistent vocal levels, using compressors, limiters, and manual gain riding. Sometimes it seems as if singers are deliberately doing their best to vary the level by bobbing and weaving in and out of the mic’s pickup pattern and moving the mic closer and further from their mouths as they sing. Obviously they don’t do this to torture us — it’s just part of the performance. But it would be very nice if we could get them to try to be as consistent as possible in terms of mic direction and distance. I usually instruct them to get the mic at a consistent 2-3 inches from their mouth, and just a bit off-axis so they’re not singing straight into the capsule. Truth be known, most modern handheld mics have sufficient windscreen material to get a lot of the plosives (P-pops and the like) under control. But having the vocalist sing into the mic at just a bit of an angle helps to further reduce the problem.
The one exception to the notion of consistent mouth-to-capsule distance is that of a very dynamic performance. Our singer may be at whisper level at one moment and at full belt a moment later. It is eminently helpful to us if they are willing and able to either pull the mic away from their mouth during the loudest parts and bring it back close for the quietest — or to turn the mouth to the side and/or back off a touch in the case of a mic mounted on a stand.
Our discussion has thus far been limited to handheld mics, but it’s also important to address mounted mics as well — particularly pulpit mics. I want to draw a distinction between handheld and pulpit mics because, generally speaking, handhelds are more likely to be used for singing, and pulpit mics are more likely to be used for speaking. Either way, all the same rules apply. We want folks to do their level best to maintain a consistent distance from the mic, and to avoid proximity effect (unless it’s intended for a special effect), and to take care to avoid an angle that increases the likelihood of plosives. Also, if our pulpit mic exhibits a cardioid pattern, we’ll need to train our speakers to avoid bobbing and weaving while they’re delivering their message. This could be a tall order, so we may even consider deploying an omnidirectional mic in the pulpit or talking them into donning a headset mic.
Back to School!
So how do we actually get our folks to play nice with our mics? I would respectfully submit that the answer is summarized in two words: formal training. The training part of that phrase should be pretty obvious, but I would say that it must indeed also be formal, because if it’s not, it may be glossed over and given short shrift. In my opinion, it’s so important that it warrants an annual refresher course, even for the veterans among our vocalists and speakers. Sometimes bad habits can creep in, and if we insist on annual training, we accomplish two things: initial training for the newest folks who haven’t been around a while, and a nice reminder for the veterans who’ve been around for a while.
I’d recommend setting up a demonstration in which a handheld mic is right on the verge of feedback in the 1-4 kHz range, and let each trainee try all the various right and wrong ways to hold the mic so they can experience the differences. Of course, we’d also want to show them proper technique in terms of the angle and distance of the mic, and also how to help maintain consistent gain by moving the mic based on the SPL produced by the mouth. And obviously, if we have new, untrained folks arrive in advance of the next annual training session, it makes sense to provide ad hoc training for them, particularly if their mic technique is atrocious and detrimental to our goals. Bottom line — we must train everyone who uses microphones how to properly do so — and if we’re diligent about this, we can all enjoy noticeable improvements in the quality of our audio.
John McJunkin is the chief engineer and staff producer in the studio at Grand Canyon University.
