Microphone Types

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There are many online resources available that can tell you all about the nuances of microphones, and I’m not going to try to reproduce them here. Instead, I want to give you a quick primer on a few different types of microphones and what they can be used for.

Omnidirectional Microphones

These do pretty much what they say they do: record sound from all directions. They will pick up more from the front than the back, but they give you a good dose of all of the sound in the area.

Omnidirectional mics are great for getting the feel for a place. They will record ambient sounds without emphasizing any of them too much (besides the fact that physics dictates that nearby sounds will be way louder than far away sounds). In an interview, an omni mic will give a sense that you are in a location, but can pick up background sounds in a distracting way if you aren’t careful. Put one close enough to the subject and you’ll get a good mix of foreground and background sound — provided that the setting isn’t too loud.

Cardioid Microphones

These are more directional than omni mics and are sometimes called unidirectional microphones. They come in different “amounts of directionality,” from slightly directional to very directional. They also pick up very well from the back of the mic — where the handle of a handheld mic usually is. This means that some cardioid mics are very susceptible to handling noise and vibration.

Using a cardioid mic gives you that “radio sound” you are used to from DJs and talk radio hosts. This is because of something called the Proximity Effect that enhances the bass in a voice when the microphone is very close to the speaker’s mouth (close as in a few inches away). The main reason for using a cardioid mic in a podcast is to reduce the background environmental noise. A directional mic will not eliminate background noise, but it will make it less distracting.

Hypercardiod Microphones

These can also be called shotgun microphones, depending upon their characteristics and shape. Hypercardiod microphones pick up sound from a very specific area in front of the mic, and can share handling-noise issues with their less-directional cardiod siblings.

These mics are not magical, so don’t expect to use one to record a speaker 20 feet away and get amazing sound. For interviews and other spoken-word recordings, you should treat these microphones just like the others. They will allow you to record in situations that would be hard with other mics, and they can give you a studio-like sound in the field, but they don’t work miracles.

Stereo vs. Mono

The difference here should be pretty obvious: In stereo, the left and right speakers produce different sounds, and in mono they produce the same sound. When it comes to microphones, you need two to record stereo and one to record mono. Of course, there are many microphones that include two recording elements in one casing, so stereo doesn’t always mean two wires running to two devices.

Unless you are podcasting music, stereo isn’t a necessity for most shows. In fact, getting really close to a stereo mic can cause some very weird issues with your sound. However, an exception to the “stereo is unnecessary” rule can be seen in my Hat Mics post, where I use a pair of stereo mics to record two separate tracks into one file.

Specialty Mics

There are many types of microphones designed for very specific tasks. I won’t go into the details of all of them but here are a couple of types that could be of interest to podcasters:

XY Stereo Microphones: For recording a more directional, authentic-sounding stereo sound. These are some of the only stereo mics that can easily be used for voice recording like a mono mic without sounding strange. (See the built-in mics of the Zoom H4 for an example of an XY setup.)

In- Ear Binaural Microphones: Because they sit in your ears, mics like these from Sound Professionals give a 3D feel by recording exactly what you hear. The catch is that they only give that 3D feel through headphones, otherwise they are just stereo mics. You can hear a recording I made with this type of microphone below.

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Why I use “Cheap Gear”

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I’m a professional podcaster with over a hundred episodes of multiple podcasts under my belt. I am a podcast consultant who has helped tweak or launch high-profile podcasts. In both of these capacities, I’ve gotten rave reviews of my shows’ sound quality from untrained listeners and professional radio producers alike. To do all of that, I must have some pretty snazzy gear, right?


For Boston Behind the Scenes (my personal podcast), I use a $90 iRiver iFP-799 and a $15 Giant Squid Audio Lab Mini Gold-Plated Omni Mic shown in the picture. I record my intro and outro with a USB microphone and edit my show with the GarageBand software that came free with my computer.

For the award-winning Current Science & Technology Podcast (my professional show), I use two microphones scrounged out of the Museum of Science’s closets and plugged into an inexpensive mixer/interface from Alesis. When I go into the field, I use another iRiver that I bought on eBay for $45.

Why don’t I have a fancy digital recorder like the M-Audio Microtrack 24/96 or the Marantz PMD671? Because what I have is the best setup for what I do. I’ve tried the Microtrack — I was very unhappy with the interface, the loooong startup time, and the non-replaceable battery. The Marantz (and the far less expensive Zoom H4) has XLR inputs with phantom power, but lacks a 1/8″ mic jack for use with my trusty “hat mics.” In any case, these recorders are beyond what the average podcaster needs.

So, what does the average podcaster need? A simple, reliable, and decent-sounding setup that doesn’t break the bank. My iRiver and one-inch mic provide exactly that. Because the two together weigh only a few ounces, I can carry them everywhere and always be ready to record. And because the recorder will run all day on one AA battery, I never have to wonder if I’ll have the power I need for a session — a 40-hour backup system is available at the convenience store across the street for $2.49. Oh, and contrary to the argument I’ve heard that “You’ll be seen as a fool showing up to an interview with a tiny iRiver,” everyone I’ve ever interviewed has seen it as more advanced and impressive because of its size.

Inexpensive gear may not have all the bells and whistles of its more pricey cousins, but it can produce high-quality work. I don’t need XLR inputs for most of my recordings, and level meters are secondary to monitoring with headphones. These things would be conveniences, but I would lose the instant startup time, one-button recording, and long battery life I’m used to — all while spending $300-$1000. Anyway, the sound quality of an interview depends far more on proper microphone placement and background noise than on fancy compressors or 96 kHz sampling — especially when the output is a 64 kbps MP3!

One last important point: low price can have another advantage — peace of mind. I recently advised an explorer interested in recording audio at the North Pole (on a $500 budget) to pick up a few iRivers from eBay rather than buying an expensive recorder. This was due to the harsh conditions he’d be using them in. If he dropped a Microtrack in a snowdrift or froze its non-replaceable battery, he wouldn’t have any way to make recordings. In some cases, four or five $75 devices are a much better idea than one $400 one.

I believe that when starting out, you should get equipment that is good enough to do the job, but not so expensive or complex that it gets in the way. If you start to feel limited by the equipment — and are sure you can’t leapfrog those feelings with improved technique — maybe then it is time to get some new gear. When you do, you can still use the old gear as a backup.

For podcasting, what do you think the best gear/technique mix is?



100 Million iPods

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Yesterday, Apple announced that 100 million iPods have been sold since the release of the original 5GB iPod on November 10th, 2001.

That’s an average of 50,607 per day (or a bit better than one every two seconds).

For comparison, Sony sold about 150 million Walkman cassette players between 1979 and 1995 (when they started to die off in favor of the Discman CD Player). That’s 50% more Walkman players in 16 ½ years than the iPods sold the less than 5 ½ years they have been on the market.

In the original press release announcing the iPod in 2001, Steve Jobs was quoted as saying:

“With iPod, Apple has invented a whole new category of digital music player that lets you put your entire music collection in your pocket and listen to it wherever you go. With iPod, listening to music will never be the same again.”

It sure looks like he was right.

Congratulations, Apple!

100 Million iPods

© 2010 Adam Weiss: Podcast Consultant