Microphones 101: Part IV - What to Look for in a Microphone

Over the past few days we here at PAL have been diving deep into wonderful world of mics with our Microphones 101 segment  and giving you plenty of info to help better understand those oh-so important pieces of equipment. We started off by breaking down the more common types of mics found in studio recording, kept it going by exploring different microphone polar patterns  along with what each of them mean, and finally, took a look at the causes Radio Frequency Interference and how to cure them. Alright, so now that we know all of this information, it’s not going to do us any good unless we can apply it towards finding that perfect microphone for the job. Sounds easy, right? Well, not as easy as you might have hoped for as there is no real cut and dry answer for what’s best. It depends on a lot of things actually. A certain mic that works perfect for one job might be completely wrong for another. To make matters worse, some mics that work great within a certain key might not sound so hot in another. While all this might sound like way too much to bother with, learning what to look for when selecting a mic can make the whole process much more bearable than you actually might think.


Knowing What Works When

It’s fairly obvious that with any sort of important purchase its best to know a little something about it in order to make a smart buy. If it’s a new car, you might want to check the MPG or added features. If it’s a new TV, size and connection options tend to be important deciding factors, but what about microphones? The type? Sure, that’s a good start but what then? Let’s say you are looking at two condenser microphones that are similarly priced, how would you know which of the two will work best for you? Well, enough of these rhetorical questions, let’s get going with some answers!

The first thing that should be taken into consideration is that when it comes to any kind of microphone, their inherent design is pretty much a battle of tradeoffs – usually between accuracy and noise. As far as accuracy goes, the most accurate tend to be smaller omnidirectional microphones but the problem is as the size decreases, the noise they pick up tends to go up. The reason for this is the smaller diaphragm; they simply don’t put out as strong a signal as larger diaphragms so the output signal has to be amplified, upping the noise along with it. And as you can imagine, a larger diaphragm mic will give you the opposite problem – less noise but less accuracy. Depending on what you need – more accuracy or less noise – the diaphragm size will be the best thing to start to look at.

Also, you have to consider the type of microphone and their inherent pros and cons. Condenser mics for example only work well for certain things. For those of you that remember part one of this 101 series, a large diaphragm condenser mic doesn’t handle well when exposed to sound coming from all directions at once but work beautifully with smaller, more direct  and quieter sources such as a voice. This is why large diaphragm condenser mics are used best as a vocal mic. Small diaphragm condensers on the other hand have better off axis response (meaning they can handle loud sounds coming from several directions at once) so they are typically used for recording larger sounds such as guitars, a group of singers or certain pieces of a drum kit. The trade off here is that since it is smaller, it won’t be nearly as sensitive and accurate as the larger diaphragm mic. Small diaphragms are more accurate but can’t handle noise so they tend to be used for vocals while large diaphragms can handle more noise but are less accurate so are used more for instruments – got it? But don’t forget that these are simply suggestions on what should work best and not an unbreakable rule. If you have a quiet instrument for example, you should probably go with the vocal mic (large diaphragm condenser) instead of the small since you will gain more accuracy and noise won’t really be an issue. Always think of what the mic will be used for and what you are willing to give up in order to gain something more favorable.


Same Mic, Different Problem

Alright, not so confusing so far, right? Unfortunately, there’s another pretty important thing that should always be considered when looking at mics; most microphones are never truly flat, that is to say that due to the nature of how they work, most have small peaks and dips in frequency response that can occur all over. Even if you take a look at an individual mic’s frequency response chart (polar pattern) it will still be hard to gauge these peaks and dips since they are usually pretty small and glossed over on the chart – mainly because even two mics of the same make and model will have these peaks and dips at different registers, meaning that these charts are more or less an average of what you should expect, but the peaks and dips mentioned are still very much there. Now, these peaks and dips only become a problem when a note played or sung coincides with their frequency, meaning that while a mic may sound perfect when recording in a certain key or register, it possible for that same mic won’t react as well when played in another. Also, the same mic will respond to individual instruments or singers differently, making choosing one that will sound perfect on just about anyone or anything virtually impossible. While this little fact may sound a bit overwhelming for newer players, simply take it as a reason to be wary of people who tend to compare two mics since – as we just touched – what works for one person might end up very different for another. But don’t let that deter you from searching for something that works for you, just be aware that different situations will end up calling for different microphones and a mic that might not be working for a certain track might still sound perfect when applied elsewhere.

Don't forget to check out a mic's polar pattern

When comparing mics, also be aware that unless you’ve have plenty of experience and good ear training, it can be easy to confuse these small peaks and dips for something else. Those who are newer to microphones tend to hear differences between mics in more simplified ways, such as how loud or bright they sound. The reason I bring this up is so that when you are out there comparing mics, make sure you’re not confusing a mic’s “brighter”  or "clearer" quality for one of those peaks (or even treble boost).


One Last Thing

Alright, and as a final little tip, be cautious of mics that tend to sound louder; while this is only a general tip and do not universally apply to all loud mics, louder microphones tend to sacrifice accuracy for their bigger sound. But always keep in mind that just because it’s “less accurate” doesn’t essentially make it a bad thing – if it complements the track, it can definitely be a plus but just be aware that it is “less accurate.”

Essentially, when it comes to picking up a perfect mic it is pretty much a game of managing the right tradeoffs that will work best for you over the long run. Also, keep in mind that certain mics tend to work better for different jobs. But hey, now that you know what to look for in a microphone, how about some light browsing?!

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