Selecting a Microphone for the Right Application
The History and Uses of Microphones
The microphone was first invented in the 1870’s and has advanced over the last 140 years as technology has allowed. The type of materials, circuitry, and tools these days have made precision microphones of all types and for all uses imaginable. Microphone options for live environments are so numbered that it would be nearly impossible to try to cover even a small portion in comparison. So, I am going to talk about microphones on a general level with some references that may be familiar.
The use of microphones, types, and brands are so incredibly subjective that even writing this may sound one-sided based on my opinion and experience. Just know that at the end of the day what makes the whole process of selecting microphones enjoyable is the ability to experiment and try different products and techniques to achieve the sound you want. Let’s dive in a little.
The Vocal Mic
We can start with the most subjective – the vocal mic. I recently had the opportunity to be a part of a microphone shootout, where a performer sang into a handful of different microphones. This selection of mics covered the wide range of styles, from the simplest to the most expensive. The environment was the most ideal for live use and in the end, the artist picked the most basic, the Shure SM-58. It surprised a few of us but really it made sense for this performer. Every voice is going to sound different through each microphone and it’s important to list and look for a few features and how they suit your needs. For example, frequency response, proximity effect, handling noise if you hold the mic, and SPL handling. Frequency response is important depending on the timbre of the voice. Proximity effect can really affect the performance of a microphone. If the vocalist is too far away from the microphone the sound may be too thin, causing the gain to be boosted and possibly resulting in feedback issues. Whereas if the vocalist sings closer to the mic, now the sound engineer can adjust the gain properly, EQ the channel properly, and get the tone desired for that environment. If the singer is holding the microphone, you want a mic that will not transfer the handling noise as much. Some are better than others. Lastly is the SPL handling. If the vocalist has a powerful voice, you don’t want to end up with a mic that is ultra-sensitive as you may risk distorting the sound at the mic. If a microphone is chosen that has a higher SPL handling then no distortion will occur and the sound engineer will have better control over the signal.
Dynamic vs. Condenser Microphones
Condenser mics have a much higher sensitivity level and often a broader frequency response as a result. Depending on the environment and the microphone chosen, a condenser microphone may be too sensitive and only cause feedback problems. This is where a dynamic microphone could be a better choice. The dynamic mic is typically less sensitive, better-rounded in tone and because it has a smaller proximity effect than a condenser, would result in having to sing right on top of the microphone to achieve the best signal quality and level.
You can take these basic principles and apply them to anything you are using a microphone with. As an example, let’s talk about mic’ing a guitar amplifier. There are techniques based around where to point the mic in relation to the speaker cone, and if it’s an open back guitar cabinet, you could put one mic on front and one in back then flipping the phase on one of those two to achieve a fatter sound. In the right environment, you could use a condenser microphone on a guitar amp. There is typically enough gain off of the front of the cabinet that you don’t have to boost the gain on the mic. Just make sure it can handle the SPL level coming out of the cabinet. You could double up the mics on a guitar cabinet by using one condenser and one dynamic to achieve two distinct tones to mix.
Drum Kick Microphone
Setting up mics on a drum kit can be tricky at first. But once you find out what works for your environment, it gets easier and you are able to start fine tuning and tweaking until you find the desired sound. A kick drum microphone is another one of those that can be quite subjective, and not just how you think it sounds, but how it interacts with that particular drum kit and sound system. Many factors come in to play when dealing with low end response. In some cases, in studio environments, engineers will place multiple microphones in and around a kick drum and capture those all in order to find the best sound later during mix down.
Principles for Selecting Microphones
So, when people ask me what microphone to recommend for them, you can see it’s not as simple as just naming my favorite model. It may have worked well for me, but may not be the best fit for someone else.
The general principles of selecting microphones can be applied to all instruments, voices, or audio sources. Sensitivity, polar pattern, dynamic or condenser, and frequency response all play key parts in deciding what will work in your particular application. If you have the ability to borrow, rent or just buy different microphones to try out, this will give you a chance to really A/B the different performance qualities of each one. When you do so, take notes. You may find that the quality of one mic that may not be suitable for one application, may turn out to be perfect for another.
Cheers to choosing,
Erik Beyer, Regional VP of Sales for CLAIR Solutions
Guest Blogger for Audio Visual Bend
Erik manages current and new client relationships, development partners, subcontractors, and vendors, handles AVL system design for houses of worship, sporting facilities, venues, healthcare, and commercial AV.