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Shure Beta 53 review (for linguists)
Figure 1. Shure Beta 53 microphone, neckband, and the RPM626 pre-amplifier Construction and designThe Shure Beta 53 is a miniature electrect condenser capsule attached to a boom that can be further attached to a wire frame that is supposed to be worn around the neck. The neckband has a similar design to the Beyerdynamic Opus 55 MkII and Sennheiser HSP2. Because the boom is detachable from the wire frame, it can be fitted onto a different headset, which is what I do. It requires some simple DIY work but it is worth it for my use. The neckband is not particularly easy to put on, and the microphone boom rests on the talker's cheek. This is rather problematic, especially for people with facial hair, as the rubbing of the microphone against the skin or stubble adds an annoying handling noise to the recording. This design is perfect for stage use, whereby the speaker can find the right fit by adjusting the wire frame, but it would be almost impossible in the field without making your subject feel awkward. Detailed electrical and acoustic specifications can be found on the Shure web site. I will just mention that this microphone has a lower sensitivity (open circuit voltage level) than the Beyerdynamic Opus 55 MkII (3.16 mV), which, in my tests, results in the fact that you need to set the pre-amplifier gain about 6 dB higher in order to get the same output level. For my type of research, this is a disadvantage because higher gain always results in higher pre-amp noise and causes the microphone to pick up more noise from environment. It probably doesn't matter for singers and other performers who use a high-intensity voice with this microphone, but for collecting speech recordings, I prefer the sensitivity of the Beyerdynamic Opus 55 MkII. It is a personal preference, of course. Frequency responseThis is where the Shure Beta 53 really shines. The frequency response is broad and flat, especially in the low-end, which matters most to me (see more on this topic below). Many omnidirectional microphones have a low-frequency roll-off (by design), which is useful for performers, but creates a certain level of bias for speech analysis. Figure 2 shows the frequency response of the Shure Beta 53 according to the manufacturer. My tests seem to confirm the flat low-end.
Figure 2. Frequency response of Shure Beta 53 (with filtered cap) according to manufacturers Power requirementsYou must use the RPM626 pre-amplifier with this microphone. The pre-amplifier connects the microphone's cord (terminated with a female four-pin mini XLR (TA4F)) to the XLR input of your recorder. You must supply phantom power with this microphone. I found that the Beta 53 is forgiving of phantom power lower than 48 V, which is sometimes all you get on field recorders. Shure used to make a battery-powered belt pack, which, sadly, has been discontinued. I was fortunate to buy it while it was still available, and it is fantastic if phantom power is not available on your recorder, or if you want to save your recorder's batteries. What I likeIt is a very nice microphone. It is sturdy, it sounds good. It is readily available in many parts of the world. Shure has very good technical support, at least in my experience. My wish listBattery-powered belt-packI realize that this type of microphone is designed primarily to be used with wireless transmitters. However, I would really love a battery-powered belt-pack that would provide phantom power and a mini-to-standard XLR interface. Audio-Technica AT831b, which is another one of my all-time favorites, is a great example of that kind of design. It can be powered by a battery or regular phantom power. This is perfect in the field if you want to use a recorder that doesn't have on-board phantom power. The headbandI make my own headbands, but it would be great if the microphone was offered with a traditional headband, such as those used in telephone headsets. That would be so nice! Audio testsComparison with Opus 55 MkIII made a simultaneous recording with the Beyerdynamic Opus 55 MkII (left channel) and Shure Beta 53 (right channel) in a sound-treated room with only the noise of a laptop computer about 4 feet away from the microphones. The microphones were calibrated to obtain the same output signal level at 1,000 Hz. I used USBPre at 48,000 Hz / 24-bit. Figure 3 shows a direct comparison of FFT spectra of /o/ taken at the same point in time. The spectra look very similar; they both show a very natural frequency envelope. Download the file and look at it using your favorite spectral analysis software. Listen to MP3 at 256 kbps:
Figure 3. Comparison of FFT spectra of /o/ between the Beta 53 (left panel) and Opus 55 MkII (right panel) taken at the same point in time. NoiseI was interested in seeing how the Shure Beta 53 compares to the Beyerdynamic Opus 55 MkII. Both microphones are excellent, no doubt. Overall, I was happier with the performance of the Beyerdynamic, particularly because the Beta 53 required about 6 dB more gain to obtain the same output level. This resulted in more recorded noise, partly from the pre-amplifier, and partly from the environment. Figure 3 below shows a comparison of ambient noise spectra (both at 70 dB SPL) of Opus 55 MkII (left panel) and Beta 53 (right panel). The recordings were made simultaneously, in a sound-proof booth, calibrated to the same output level. The only source of ambient noise in the booth was a laptop computer (about 4 feet from the microphones), which was done deliberately to show real-world noise performance. We rarely record in sound-proof environments in the field. It is important to show the influence of a quiet, but controlled noise source (laptop computer) on overall noise levels in the resulting audio files. Clearly, the Opus 55 MkiI wins. This will likely be a negligible difference for most types of speech analysis, but the difference is real, so I need to mention it to be fair.
Figure 3. Comparison of ambient noise spectra of Opus 55 MkII (left panel) and Shure Beta 53 (right panel) Low frequenciesThe Shure Beta 53 clearly shows a very natural evelope in the low frequencies. The manufacturer's frequency response data show an attenuation (roll-off) starting at around 50 Hz, but it does not seem to affect the spectrum of a typical male voice. Shure engineers probably decided to use the slight roll-off because it helps get rid of some of the low-frequency rumble that is present in many recording environments. Besides, it is not easy to implement extended flat frequency response below 50 Hz.
Figure 4. FFT of /o/ showing a natural and detailed spectral envelope of speech The spectrogram (Figure 5) shows really good detail and a natural frequency envelope. You can perform very successful acoustic analysis of files produced with the Beta 53. The microphone has a slightly greater susceptibility to popping than the Opus 55, but you can easily counter that by using a better pop filter. Also, the Shure Beta 53 has an adjustable cap that will affect higher frequencies. You want to use the filtered cap in order not to emphasize high frequencies (above 10,000 Hz) too much.
Figure 5. Spectrogram of a phrase "czarna krowa" with Shure Beta 53 at 48,000 Hz / 24-bit in a sound-proof booth ConclusionAfter working with the Shure Beta 53 for about a year now, I feel confident recommending it as a speech acquisition microphone. I like the Beyerdynamic Opus 55 MkII better, but the Shure has excellent worldwide availability and customer service, so you may find it easier to buy one, outside of Europe and the USA. Download original files
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Shure Beta 53 omnidirectional headworn (headset) microphone (Figure 1) is one of the handful of professional, flat-response, headworn omnidirectional microphones available today that are suitable for recording high-quality speech signals for acoustic analysis in the field. It is one of the microphones I recommend in my 
