Microphone Performance Tests: Your Built-in Mic Isn't Good Enough

Recently I hosted a webinar with Sonic Foundry called Fool Proof Tips to Produce the Most Polished Webcasts on the Planet. One of the subjects that I covered was microphone options for producing the best quality sound. I was interested in two scenarios, the first a single camera personal webcast shot from close range, and the second an interview shot from about eight to ten feet away, or more.

In the first scenario, you might be tempted to use the webcam and internal microphone that now ship standard on most notebooks, including the HP 8710p and MacBook Pro that I own. While that's hard to beat for convenience, some camera-related tests that I performed for the same webinar convinced me that video quality output by internal devices is so subpar that it shouldn't be used for business—a $500 DV camcorder produces noticeably higher quality, even when encoded to around 1 Mbps at 640x480 resolution.

Of course, once you decide to use an external camcorder, the next question is whether to trust the internal microphone of that camcorder for audio, or whether a shotgun microphone does a better job. I like a shotgun microphone because they're easier to setup and use than wireless lavalieres and function very well in close-in interviews. So the first question I wanted to answer for the webinar and for this review was how the internal microphone of a prosumer camcorder compared to a reasonably priced shotgun microphone.

The second question related to wireless lavaliere systems. I has purchased an Audio 2000's 6032uf UHF Dual Channel Wireless lavaliere system a few months back for around $130, and while the sound was good, the system picks up too much ambient noise for my liking, and the vocals were slightly muffled. I was curious to learn how audio quality compared to a system in the $700 to $1,000 price range.

I contacted Azden who contributed two products to the cause, the $149 SGM-1X shotgun  microphone and the 330 ULT UHF Wireless Combo system ($699, both prices at Amazon.com). I used a similar test procedure for both systems, testing with a Panasonic HMC-150 AVCHD camcorder that provided the control necessary to capture audio from the different devices to different channels in the audio file.

Specifically, in the first test, I captured audio from the Azden shotgun microphone in the left channel, and audio captured from the internal microphone on the right. In the second test, I captured audio from the Audio2000's system on the left, and the Azden system on the right. With both tests, I controlled volume manually to produce similar levels from both audio devices.

When playing back the videos, you can toggle the sound to the left and right channels to assess the quality captured by the respective devices in each test. So after I describe each product a bit, and show you the waveforms, you can play the videos and draw your own conclusions about comparable quality

The SGM-1X Shotgun Microphone

The SGM-1X is a battery-powered microphone that connects to your camcorder via XLR. It ships with a shock-mounted cold accessory shoe and windscreen, but no XLR cable, so you should pick up a short male/female cable when you buy the microphone. You'll also need a AAA battery to power the microphone, though the rated battery life is 1,000 hours, so you should be set for awhile after buying the first.

The only controls are the on/off switch and a low-cut filter switch designed to reduce low frequency noise. The mount comes with two holes drilled on the bottom that should allow you to screw it on some microphone stands, though the holes didn't fit my Shure stands. Figure 3 shows the setup that I used for this test, including using fluorescent overhead lights to test the low-cut filter on the shotgun microphone.

Figure 4 shows waveform from the two devices, with the internal microphone on the bottom showing a bit more noise, which is the fuzzy signal surrounding the center line of each audio channel. In addition, the waveform in the shotgun microphone shows more distinct and higher peaks, which indicates a greater dynamic range in the pick-up pattern, as well as better clarity.

If you listen to the video, and toggle between the two sources, you'll notice just that. There's a lot more noise in the internal microphone, and it sounds a touch muffled with noticeable echoing. The shotgun microphone isn't perfect, and you'll hear better quality with Azden lavaliere microphone below, but sometimes lavalieres just aren't practical, and the shotgun delivers noticeable improvement over the internal microphone.

In the case of an even cheaper camcorder with the microphone buried in the body of the device, rather than sitting out front on the handle, the disparity would be even greater. Basically, unless you're capturing audio solely for reference purposes to synch up with audio captured from another source, you should use a shotgun like the Azden over the internal microphone of the camcorder.

Dueling Lavalieres

The next stage of testing compared a $130 Audio 2000's AWM 6032uf VHF dual-channel lavaliere system with a $700 dual-channel 330ULT UHF wireless system from Azden. Back in March 2011, I reviewed the Audio 2000 system. To summarize my findings, in a controlled environment with little ambient noise, the system performed well, though the microphones picked up a surprising amount of ambient noise in a noisy environment.

Briefly, the Azden 330ULT is a dual-channel, battery-powered system with a camera-mounted receiver, which makes it very portable and easy to use in the field. In contrast, the Audio 2000's receiver is a line-powered, book-sized device, which isn't nearly as portable.

The Azden system transmits via UHF where the Audio 2000's uses VHF. Basically, UHF systems provide more channels, decreasing the risk of interference with other wireless devices, but work at higher frequencies and require more expensive components. If you're shooting a dual-mike wedding out in the country, VHF should probably perform as well as UHF. If you're shooting a ten microphone performance in mid-town Manhattan, UHF is the way to go.

Other niceties on the Azden system include a more granular battery meter with levels (the Audio 2000's just has a battery low light), and all cables required to connect to your camcorder or sound system. With the Audio 2000's system, you have to supply your own XLR cable. Table 1 summarizes the most important features of the two systems.

[table id=1 /]

Audio Quality

Beyond the specs, how did audio quality compare? As you can see in Figure 6, the Azden system (on the bottom) did a much better job eliminating extraneous noise than the Audio 2000's system on top. This is the audio captured when I was walking to my stool and sitting down for the shoot, and all audio was extraneous. I've left this footage in the video you can watch and listen to below so you can hear the difference as well as see it in the waveform.

Otherwise, within the main waveform itself, the difference is much more difficult to see, though when you listen to the audio, you'll have no problem telling the two devices apart. What I hear in the audio is that the Azden system is much more crisp and clear, while the Audio 2000's system is more muddled, though a touch brighter. Both systems produced a very slight hum, though the Azden's was much more regular, so it would be easier to filter out for on-demand video.

Play the video below to listen to the two systems, with the Audio 2000's on the left, and the Azden on the right.

Obviously, the Azden and Audio 2000's systems aren't the only two systems on the planet, and the price difference is significant. If you can live with an AC-powered system, you can probably find a cheaper alternative to the Azden that delivers better quality than the Audio 2000's system.

On the other hand, if you're shooting on the go, and need two channels, you'll find the Azden system at the bottom of the price range for dual-channel camera mount systems, which range into the low four figures. It's nice to know that in addition to portability, you get a nice upgrade in sound quality over much cheaper systems, particularly relating to the ability to minimize ambient noise.

Jan Ozer's article first appeared on OnlineVideo.net