Choosing the highest quality microphone option

So those are the microphones and the ways they connect. But how do they perform?

To test performance, we used a high-quality, digitized recording of a woman speaking, played back over computer speakers at a standardized volume. To create ambient sound, we left all office equipment running, which created a distinct hum of background noise.

We set up the VX2000 approximately ten feet away from the speakers, and then recorded the audio using all the microphones shown in Figure 2. During each recording, we used the VX2000’s manual gain controls to boost the audio to an acceptable level. For this reason, while you’ll notice some minor volume differences in the waveforms you’re about to review, the most significant differences will be in the detail captured by the microphone and the amount of noise in the signal.

Let’s start by looking at the difference between the best and the worst, shown in Figure 6, which contains waveforms produced by the camcorder microphone and the Shure lavaliere microphone. You’ll notice that the waveform on the bottom shows higher peaks and valleys, indicating higher volume. You’ll also notice that when there was no speech, the line of noise produced by the camcorder was noticeably thicker, indicating more ambient noise.


Figure 6.  Comparing the quality of audio captured by the VX2000’s microphone and the Shure Lavaliere.

Most striking, however, is the detail missed by the camcorder. As indicated in the picture, the woman speaking is saying the word “tutorial,” and there are noticeable peaks at the “t”s and “i” in “tutorial” with the Shure lavaliere. These peaks are not present in the camcorder mic’s waveform, indicating the speech was much more muffled and harder to understand. If you listened to the results, you would find the Shure lavaliere audio clear, crisp, and natural, while the camcorder audio sounded tinny, and almost like it was shot in a barrel or other close quarters.

Overall, the results produced by the Sony Wireless Lavaliere system and the three Shure wired microphones were very similar and clearly superior to that produced by the two shotgun microphones. These findings are illustrated in Figure 7



Figure 7.  Comparing the Shure Lavaliere with the Sony ECM-HS1 shotgun microphone.

Again, the Shure solution produced higher volume, a crisper signal, and slightly less noise. Overall, while the ECM-HS1 and ECM-Z73C produced better audio than the camcorder microphone, the difference was much less striking than that produced by the microphones used closer to the source.

Don’t take this as a sweeping indictment of shotgun microphones. Both the Sony models are relatively inexpensive and rather small, and Shure and other vendors offer larger, more sensitive models that would likely produce better results. In the price range we surveyed in this review, however, you’ll produce the best results if you can mike up the sound source.

These conclusions noted, we turned our attention to the difference in quality produced by connecting through the RadioShack line matching transformer and the recorded output from the BeachTek DXA-8. This is shown in Figure 8.


Figure 8.  Comparing the Lavaliere microphones output captured via Radio Shack and BeachTek products.

As you can see, the RadioShack records a monaural signal, which is why there is only one waveform, while the BeachTek records the mono input into two channels. Detail in the Radio Shack waveform is quite good, and the signal is slightly less noisy than the bottom signal, which was produced through the BeachTek unit. However, the noise is less because the signal is lower than the BeachTek unit, which sounds much more vibrant. In addition, the BeachTek signal is much more nuanced than the RadioShack signal, which sounds a bit flat. Overall, most listeners would clearly prefer the BeachTek audio.

About Jan Ozer

I help companies train new technical hires in streaming media-related positions; I also help companies optimize their codec selections and encoding stacks, and evaluate new encoders and codecs.

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