Mobile Mic Shoot-Out: Get the Best Audio for Mobile Recordings
Last month I described which microphones should theoretically work with iOS and Android devices; this month, I tackle the reality and describe how the various mics reviewed below worked with an iPhone 6, an iPad Air, and a Samsung Nexus 10. I'll start with a brief description of the tests that I performed.
The mics divided into two categories: video mics and studio mics. Video mics are microphones designed to improve the quality of audio captured with video. These included the lavalier and shotgun mic included with Azden's WHD-PRO+i bundle and HK Multimedia's iRig Mic Field and iRig Mic HD. The studio mic was the Apogee Mic, which is less mobile than the other mics, but designed for and capable of production-quality voiceover and instrumental recordings.
I tested the mics two ways. First, in a totally quiet office I recorded with the mic and then with the internal mic on the tested device. This gave me a sense of the volume and quality each mic delivered. For certain mics, I turned up the sound to simulate a live environment, assessing how the mic isolated the voice from the surrounding noise.
If you're producing live video, you have to get the volume right at the event. If you're shooting for on-demand production, you can boost the volume of the captured audio in post-production. To test both scenarios, I input all captured files into Adobe Premiere Pro and output two files, one at original volume and one with sound normalized to 0 db, which is my volume target for on-demand files. This allowed me to assess each mic's suitability for live and VOD production.
As you'll read, the Azden mics had problems producing sufficient volume with my iPhone 6 and iPad Air, but performed well with a Samsung Nexus 10 tablet. So when the mics were compatible with iOS and Android, I tested on both platforms. I produced dozens of video files for these tests, of which I will share the highlights.
As an aside, my focus here was on audio, not video quality, so lighting was a bit low, and as a result the videos are grainy. I'll do better next time.
Let's start with a high point.
IK Multimedia iRig Mic HD Handheld Mic
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The iRig Mic HD ($99.03 at Amazon) is a handheld microphone that connects via the Lightning connector on your iOS device. Though HK Multimedia includes a USB cable for the mic, which should work on Macs and PCs, it did not work on my Android tablet when shooting with the camera. This is a software limitation, not a hardware issue; very few Android programs recognize USB mics at this time.
I tested the mic on an iPhone 6 that immediately recognized the mic for the camera application. The unit has gain control, which is always a plus, and a light to indicate volume status: green if good, red if clipping, which is useful although difficult to see in use. The mic is a bit sensitive to plosives (pops in your Ps and Bs), but that's more of a training issue than a problem with the mic. If you buy this mic for voiceover or similar work, buy a pop screen and windscreen.
This mic produced sufficient volume for live work with excellent, noise-free quality. It really shined in a noisy environment where its cardioid pickup pattern eliminated almost all of the surrounding noise. If you skip to the end of the video below, you'll be amazed how much better the iRig Mic HD sounds than the internal microphone of the iPhone. If I was speaking from a live event or interviewing people at a live event, this is absolutely the mic I would buy.
IK Multimedia iRig Mic Field
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The iRig Mic Field ($88.18 at Amazon) connects via the Lightning connector on your iOS device, so it's not compatible with other platforms. I tested the mic on an iPhone 6 that immediately recognized the mic for the camera application.
Like its handheld sibling, Field has gain control, plus a light that turns different colors to indicate your volume status: green if good, red if clipping, and the indicators are easy to see in use. I tested the unit at both five feet and eight feet, in quiet and noisy environments. In the quiet tests, the iPhone's internal mics produced more volume than the iRig Mic Field, and sounded nearly as good.
You can hear that in the video file shown below, which is the audio as originally captured, as opposed to optimized. With noise in the background, the internal mic on the iPhone 6 did a slightly better job isolating my voice than the iRig Mic Field. These results don't present a compelling case for the iRig Mic Field. If you're absolutely convinced you need an external mic, you should keep looking.
Azden WHD-PRO+i Lavalier Mic
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The Azden WHD-PRO+i ($244.99 at B&H) combines a shotgun and lavalier transmitter/receiver plus a TRRS to TRS adapter cable to use the system on iOS and Android mobile devices. In my tests, I immediately noticed very low levels on the iPhone 6 and iPad Air. I called tech support which related that this is a known issue with Apple devices, perhaps something to do with automatic gain control with mics that connect via the headphone jack. More on this below.
Whatever the cause, levels for both mics were very low, clearly unsuitable for live productions. Boosted in post, the levels obviously got better, but the quality advantage over the iPhone 6's internal mic was minimal in a quiet setting. In a noisy environment, both mics did a much better job isolating speech than the internal mic; you can hear that in the video below.
On the Nexus 10, the lav mic was noisy and the quality was fair-to-good. While the shotgun mic was slightly better than the lav mic in terms of quality, it produced about the same quality as the internal mic of the Nexus in a quiet environment. You can hear that in the clip below, where I boosted the audio from the shotgun mic by about 8 dB, and the internal mic by about 12 dB.
I have a lot of respect for Azden gear, and have used its wireless and shotgun mics in many productions. Azden offers a similar bundle targeted to DSLRs and consumer camcorders that ships without the TRRS to TRS adapter. It has a four-star rating on Amazon from seven reviewers, and a four-star rating on B&H from ten users. So, the gear is sound. That said, this clearly isn't a system to buy today for iOS-based productions, and if you have a Nexus 10, I would stay away.
Apogee Digital Apogee Mic
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The Apogee Mic is a studio microphone that connects to the Lightning port of iOS devices, and comes with a serial cable for use on a Mac. Like most studio mics, the Apogee is a side-address mic, which means you talk into the side of the mic. While it comes with a small stand which works well for voiceovers, you'd probably need a separate stand for a radio or TV show, which you could do given the quality this mic produces.
The Apogee is a condenser mic with a cardioid pattern, which means that it should pick up sound primarily from a single direction. In my tests, I found it extremely sensitive, and I had to shut down every device in my office to get a noise-free signal. Like the two mics from HK Multimedia, a light on the mic flashes green when volumes are good and red when too loud. I found the mic resistant to pops and sibilants, but I spoke about 12-inches from the mic, which is generally in the safe zone.
When you listen to the test clip you'll note that both the Apogee and the iPhone mics perform well, and you'll have to listen with headphones to discern the slight hollowness and echo in the internal mic on the iPhone 6. That's really more of a limitation of the test than a limit on the mic; if I had an operatic voice, or could play classical guitar, the qualitative difference would be much more evident. This mic delivers sufficient quality to produce studio recordings, and clearly could be used for professional voiceovers or similar work.
Chasing Quality on the iOS Platform
I was intrigued when Azden advised that its iOS problems might relate to Apple disabling (or otherwise adjusting) automatic gain control (AGC) when mics are attached to the headphone port, because it jibed with something I had observed when testing for a book I'm writing. Specifically, while the iPhone clearly boosted volume when conferencing via the iPhone's internal mics to compensate for low input, the iPhone seemed almost to drop volume when external mics are connected to the headphone port.
To track this down, I tried shooting with a couple of different setups. First, I used the battery-powered Audio Technica ATR-3350, which produces good levels when I record on my HP notebook. With the iPhone, the audio was muted. Here's what the waveform looked like in Premiere Pro, which is pretty much what both Azden mics looked like.
Then I connected HK Multimedia's iRig Pre, a preamp that can power XLR-based microphones like the Shure SM93 I use frequently for videos and conferencing. As you can see, the iRig Pre connects to the same headphone port as the Azden mics and ATR-3350, but it has a gain control on the right that boosted volume enough to produce a healthy looking waveform. Audio quality is good, but a touch harsh because it was too hot, though that's definitely user error on my part.
To be clear, the iPhone didn't seem to tamp down volume on mics connected via the Lightning connector, so if you can use the iRig HD Mic or Apogee, you should be good to go. From where I sit, however, to produce adequate levels with a mic connected via the iPhone or iPad's headphone jack, you need a preamp with gain control.
The iRig Pre isn't the only unit out there, but it worked well in my tests, and at $40, and a 4-star rating on Amazon (with 92 reviewers), it's worth a try. For the record, the SM93 costs $155 on Amazon, and has a 4.5 rating with 19 reviews. The iRig Pre/Shure SM93 combination also produced the best quality on the Nexus 10, so perhaps the powered preamp advice extends to Android was well.
Jan Ozer's article first appeared on OnlineVideo.net