Review: Blue Mikey Digital

A $99 digital stereo microphone and line-in adapter for recent-model Apple iDevices.

Mikey Digital on an iPhone 4S running Voice Memo.

Blue Microphones recently started shipping the Mikey Digital, an add-on stereo mike for iPhone 4, iPhone 4S, iPad, iPad 2, iPad 3, and iPod touch 4G (iOS 6 only), and Blue offered to lend me one for review. I’d been intrigued by earlier, analog Blue Mikeys at trade shows, so I jumped at the chance to look at—and listen to—this digital descendant.

Some context: I’m primarily a picture guy, not a sound guy, so I’m looking at Mikey as an iDevice add-on for double-system sound work, for location ambience, and similar film/video support roles.

Design and Features

The Mikey Digital is the third-generation Mikey from Blue. All share a similar design, being tiltable flat paddles that plug into an iDevice’s 30-pin dock connector.

The original Mikey for iPod and the Mikey 2.0 were analog devices usable on any iPod with a dock connector, 1st-3rd generation iPod touches, and iPhones up through the 3GS. Starting with the iPad, iPod touch 4G, and iPhone 4, Apple stopped supporting analog audio input on the dock connector, so Mikey had to evolve to include its own A/D converter, and Mikey Digital is the result. Mikey works on these newer iDevices, and Blue says that Mikey will also work on the latest generation, Lightning-equipped iDevices using Apple’s $30, 30-pin-to-Lightning adapter.

Mikey Digital (I’m tempted to call it the Mickey D) uses a pair of cardioid condenser mikes with a specified response of 35 Hz – 20 kHz (the variation in that range is not listed, nor does Blue publish either a frequency response curve or a polar response plot). The A/D converter outputs stereo audio at 44.1 kHz, 16 bits deep.

The mikes sit side-by-side between two black metal grilles wrapped by a matte-chrome band; the entire package, including the dock connector, measures a bit under 2.5 inches square, and it’s about half an inch thick. The dock connector tilts about 230 degrees, allowing the mike paddle to be oriented forwards or back, with seven click-stops along the way.

Mikey Digital, front view.

Mikey Digital, rear view, with sensitivity switch centered.

Backlighting reveals the two mike capsules in Mikey Digital.

There’s a rather stiff three-position slide switch on the back, and three small bicolor LEDs on the front, each indicating a switch position and its associated sensitivity. Mikey offers a low-sensitivity mode (indicated by three lines: in other words, the position for LOUD sounds), a high-sensitivity mode (with a single-line indicator, indicating quiet sounds), and an auto-gain position in the center (with a two-line symbol, e.g., who knows how loud it’ll get?).

Mikey Digital on iPhone 4S, aimed at sounds offscreen to the right.

Plugged into an iDevice, Mikey stands off about half an inch or 7 mm, allowing reasonably thin iPod/iPhone/iPad cases to be left in place during use. It blocks the adjacent headphone jack on the iPod touch, but the jacks on the iPad and iPhone 4S are well out of the way, so that live monitoring with those iDevices is easily done.

Mikey Digital on Ipad 3, running PCMRecorder.

Mikey has a 1/8″ stereo input jack on its top for line inputs. It also has a Type B mini-USB port on its side, letting you power the iDevice remotely for long recording sessions.

Mikey Digital & friends (iPhone 4S and iPod touch 4G): 1/8″ jack on top, USB on side.

Mikey is thicker than any of the iDevices it plugs into, so it’ll prop up the connector end of the iDevice when its laid on a table, and put the sensitive mike module directly in contact with that potentially noisy surface. If you plan to use Mikey with your iDevice on a table, you might want to use an iDevice case or cover that folds back and acts as an cushion, or put the iDevice on a slab of foam, a folded sweater, or some other isolating mount.

Mikey comes with a 1/4″ to 1/8″ stereo adapter and a lined carrying bag, as well as a small user guide (which you can peruse as a PDF).

What’s in the box: Mikey, manual (one side in French, the other in English), 1/4″ adapter, and bag.

Operation

You plug it in. You run a recording app. You’re done. Right?

When you plug Mikey in, its currently-selected LED glows green for a few seconds, even if your iDevice is asleep. It lights up again once a recording app starts talking to it, and stays lit until the app stops using it.

Mikey is unprovided with recording software. There used to be a free app called “Blue FiRe” specifically for Mikey, but at the time I write this, it’s unavailable. iDevices with Apple’s “Voice Memo” app can use Mikey, but only at lower quality: my iPod touch 4G records Voice Memos as mono, 44.1 kHz, 64 kbps AAC.

The full-up, paid version of Blue FiRe is the $6 FiRe 2 Field Recorder, but being the cheap bastard I am, I decided to use free apps, or paid apps on borrowed iDevices. I wound up using four: Apple’s own GarageBand on an iPhone 4S and iPad 3, TASCAM’s PCMRecorder on iPad 3, Pocket WavePad on iPad 3, and the somewhat embarrassing (but entirely functional) Awesome Recorder Free on iPad 3.

(My touch 4G is still running iOS 5.1.1 for development purposes, and indeed, that iPod ignored Mikey entirely, always using its internal mike. The other iDevices also happened to be running 5.1.1, but they saw and used Mikey with no problems.)

Of these apps, both WavePad and GarageBand recorded mono files from Mikey; Awesome Recorder Free and PCMRecorder let me choose mono or stereo as I saw fit.

PCMRecorder detects the presence of a stereo input device, but I determined that it won’t reliably enable stereo recording unless you have headphones plugged in, or plug them in while PCMRecorder is running—that is, PCMRecorder apparently needs to receive the iOS notification that a stereo output has been connected, or it won’t give you the option for stereo input. It took me a couple of days to figure that one out!

Mikey’s manual says that “[w]hen Mikey is under control of an application, all three LEDs will illuminate green in color”, but none of the apps I used caused this to occur. Blue tells me that there aren’t any current apps that control Mikey’s gain directly, but that this capability is available should app writers want it in the future.

A single green LED always tracked the position of the switch on the back: to the left (when looking at Mikey’s front) for a fixed, low-gain setting; centered for auto gain control; and to the right for a fixed, high-gain setting.

Mikey Digital on an iPhone 4S running GarageBand, operating normally.

When Mikey gets overloaded, all three LEDs flash RED for about half a second.

Mikey Digital on an iPhone 4S running GarageBand, overloaded.

In practice, the dock connector isn’t a robust field receptacle like an XLR: it’s easy to knock Mikey partially or entirely out, just as it’s easy to insert the dock plug on a slant, perhaps making some electrical connections in an unfortunate order. For that matter, the force needed to slide the sensitivity selector switch is considerably more than that required to dislodge Mikey, so if you don’t exercise due caution, you’ll pop Mikey off your iDevice, or at least disrupt its electrical connections momentarily. In these cases, Mikey sometimes gets confused, either turning off its lights completely or leaving one single LED lit regardless of switch settings.

When Mikey gets bumped loose, the iDevice falls back to its internal mike, but with the exception of GarageBand (which immediately stops recording), none of the apps I used gave me any warning that this had happened—again, this is a design fault in the apps, not something that’s Mikey’s problem.

I expect that if I were to use Mikey for serious field work, I’d use some gaffer tape to tether Mikey’s dock connector more securely to the iDevice.

The tilting head is helpful for aiming the cardioid mikes, but don’t expect shotgun-like directionality with it. When shooting iDevice video, the 115-degree swing to aim the mikes forward isn’t quite enough to aim ’em completely forward, and with the iDevice held sideways, the mikes are positioned so that the stereo separation is up-and-down, not side-to-side.

Shooting video with iPhone 4S, Mikey angled forward as far as possible.

Next: Performance and Conclusions…


Performance

Mikey Digital is noticeably better than the built-in mikes in my iPod touch 4G and iPad 3. It has a much wider response, especially on the low end, as well as audibly superior signal to noise ratios. Mikey recordings, even in mono, were more spacious and open than their iDevice-mike counterparts, which sounded like tinny telephone transmissions by comparison.

I ran lots of side-by-side analyses, but lacking proper audio test equipment and a reasonably uncolored, anechoic test chamber for pink-noise testing, I hesitate to publish actual data or post sound files (for one thing, the tonal response of Mikey was so different from that of the internal mikes that I despaired of creating “equal loudness” A/B tests that wouldn’t be unduly biased by your particular speakers or cans, or by mine). I’ll just offer up two comparative frequency plots:

Ten seconds of ambient night sound spectrum, Mikey Digital.

Ten seconds of ambient night sound spectrum, iPad 3 internal mike.

(That little spike around 2500 Hz is due to a cricket.)

On a variety of side-by-side recordings (either iPad with Mikey beside an iPod touch with internal mike, or sequential iPad recordings with and without Mikey), clips analyzed in Adobe Audition CS 5.5 were measurably superior. Compared to the iPad’s mike, Mikey recordings tended to be at least 7-10 dB cleaner (higher SNR, with much less broad-spectrum hiss); compared to the touch, Mikey was 20-30dB cleaner.

Mikey Digital won’t be mistaken for a Schoeps or a Neumann, but for a hundred bucks it’s not too shabby, and it certainly outclasses the built-in mikes in my iDevices.

Mikey’s low-gain and high-gain settings work exactly as promised, letting you record VERY LOUD NOISES as well as more delicate sounds depending on the setting. In low gain, Mikey is rated to handle 130 dB SPL, which is rather more than my iDevice’s built-in mikes are rated for (or my ears, for that matter). I wasn’t able (or willing, perhaps) to find a sound that would make Mikey clip in low gain, though I could overdrive it by tapping Mikey with my finger.

In high gain, Mikey appeared to be about 15 dB more sensitive than my iDevices’ own mikes—very handy for recording quiet ambience and room tone—though as a result, anything much louder that the 65 dB SPL that high gain is designed for will overload Mikey.

Auto-gain mode is a mixed bag: it offers the sensitivity of high-gain mode with a subtle, usually transparent AGC. For fixed-location, indoor recordings of unpredictable volume, it can be a viable choice; it handles slowly-varying audio levels without introducing objectionable artifacts.

However, the AGC responds poorly to wind rumble and impulse noises, generating brief bursts of broad-spectrum buzz as it attempts to play catch-up with rapidly-changing levels. Let even a light breeze blow over Mikey, or handle your iDevice roughly while recording, and you’ll get loud “zings” in your recording as the AGC throws multiple step changes into the audio waveform, which sound as nasty as they look.

The AGC “zing”, as waveform and spectral plots show it.

Closeup of a “zing”: rapid, repeated stepwise changes in signal gain.

Frequency analysis of the “zing”.

Scary? Sure. Solution? Turn off AGC, pick one of the fixed-gain modes, and don’t worry about it.

Both wind noise and handling noise are things to be aware of, just as they are with any other microphone.

The perforated metal screen over the mike capsules doesn’t provide any wind protection to speak of. There are “dead cat” windscreens available (use your favorite search engine to find ’em); I didn’t have any to test, but I’d certainly want to investigate ’em if I were planning to use Mikey wherever air was moving.

Since Mikey attaches directly to your iDevice, the iDevice becomes part of the microphone body, and it’s just as adept at transmitting handling noise to the mike’s pickups as any other mike body. Tapping the iDevice’s screen vigorously, shifting it in your hand, or setting it down roughly on a table are all faithfully recorded. If you hold the iDevice carefully, and tap or swipe its screen controls lightly, you can get excellent results, but handle it carelessly and you’ll hear it in your clips.

Stereo separation is nominal rather than dramatic; with a single noise generator in a large room, I could rotate my Mikey-equipped iDevice through a 180-degree angle centered on the noise, and just barely detect a panning of the source in my headphones. The stereo imaging Mikey creates serves to open up the soundscape and give it dimensionality compared to a mono source, but it’s not something I’d choose if I needed a definite sense of localization in my audio. On the flip side, this lack of distinct separation means that the up-down orientation of the pickups when shooting iDevice video isn’t much of a concern.

My sample unit consistently output the left channel a few dB hotter than the right channel. It wasn’t much, varying from 3-7 dB on average, but it was there.

Mikey’s sensitivity appears to be cardioid, as claimed; sounds up to about 60 degrees off-axis are captured with roughly equal loudness, with noticeable falloff outside that angle, and the minimum pickup happening directly behind Mikey. If you’re shooting iDevice video with Mikey angled forwards, you’ll likely notice lower audio from the folks on the side of the camera opposite Mikey than the folks in front or on Mikey’s side (not that I consider this a serious issue, mind you; I’m just trying to cover all the bases. Just be aware that your cunning plan to take over Hollywood with your iPhone could still benefit from shooting double-system; give Mikey to your soundie and have her boom her iPhone over the action while you capture the image with yours).

I tried a few recordings using the 1/8″ input on Mikey. Line-level (headphone jack) feeds from an iPod touch were easily accommodated with Mikey on low gain and the touch at 75% volume. Mike feeds from a Sennheiser MKE 400 worked on both high and low gain settings, depending on the sensitivity setting on the MKE 400.

The only problem I encountered was getting the MKE 400’s 1/8″ stereo plug properly seated in Mikey’s 1/8″ stereo jack: unless I kept it firmly pressed in with my finger, it didn’t make proper contact, and all I’d get would be low-level 60Hz hum. The patch cord I used to connect the iPod touch—without issues—has a slightly different plug design: same length overall, but the tip has a somewhat gentler retention taper and a blunter end. The patch cord is a $0.99 special from a local surplus house, while the MKE 400 is a $200 German microphone: which one would you expect to work better?

I tried another handy patch cord with yet another tip design; it was possible to seat it fully, but it was definitely a hit-or-miss affair; sometimes I’d get a good connection, sometimes just powerline buzz. Blue’s own 1/8″-to-1/4″ adapter worked fine every time. There are several reviews of Mikey Digital that mention getting nothing through the line input; I wonder if Mikey’s particular jack design is, well, a bit too particular for the variety of plugs that might be plugged into it? Blue agrees; they say, “we have a running production update to more firmly mount the jack which should fix the issue for most plugs.”

1/8″ plugs: the center two work well with Mikey. The others, not so much.

Conclusion

Mikey Digital is an inexpensive way to turn a late-model iDevice into a stereo audio field recorder. Sound quality is much improved over the built-in mikes, and the inclusion of a 1/8″ stereo input jack lets you connect other sound sources though Mikey’s A/D converter for better quality than the iDevice’s own converter allows.

Is it a no-brainer replacement for dedicated field recorders? Not quite. Like all dock-connector accessories, Mikey is limited in the robustness of its attachment to your iDevice. Mikey’s sensitivity switch is a bit too stiff for my liking, and its 1/8″ input jack is finicky about the plugs it’ll make proper contact with (though later builds should improve this). Mikey’s AGC complains noisily about wind rumble and impulse noises: switch off AGC in favor of fixed gain for best results. Stereo imaging is better described as “adequate” rather than “vivid”.

But if you can’t justify a full-fat, multi-hundred-dollar recorder, and are willing to handle Mikey with a bit of care and delicacy, it’ll turn your iDevice into a decent stand-in, with sound quality far superior to what that pricey bit of Apple shiny-shiny can record on its own.

Pros

  • Very good sound quality for a sub-$100 stereo digital microphone.
  • Much higher sensitivity than an iDevice’s built-in mike.
  • Much higher overload level than an iDevice’s built-in mike.
  • Cardioid pattern offers some directionality without excess directional coloration.
  • 1/8″ stereo input jack with 1/4″ stereo adapter.
  • USB power pass-through for remote powering/charging.
  • Small, lightweight, and inexpensive.

Cons

  • AGC “zings” noisily when it tries to handle sudden transients and wind rumble (fortunately, AGC can be switched off).
  • 1/8″ jack is very sensitive to plug design (should be better on later builds).
  • Microphone stereo imaging is minimal.

Cautions

  • Dock connector is easy to dislodge and knock loose.
  • Sensitivity slide switch is very stiff; needs careful manipulation to avoid pulling Mikey out of the dock connector.
  • Mikey is very sensitive to wind noise; you’ll need a dead cat (dead kitten?) for outdoor use, and a breath/pop filter for indoor vocals.
  • ACG is best used only when levels can’t be determined beforehand and you can guarantee that “zing”-inducing transients / rumbles won’t be present.
  • Works only with iPod touch 4G or later, iPhone 4 or later, or iPad (any of ’em).
  • Using with iPod touch 4G requires iOS 6 or later.
  • Using with Lightning-equipped iDevices (iPod touch 5G, iPhone 5, iPad mini, iPad 4, etc.) requires $30 dock-to-Lightning adapter.

Disclosure: Blue sent me a Mikey Digital for review and paid for its return when I was done with it. I previously purchased my own bits of Apple shiny-shiny as well as Adobe software at market prices; I also borrowed an iPhone and iPad running GarageBand, and downloaded free apps as mentioned above, in order to complete this review.

Blue reviewed this article for technical accuracy. I incorporated their comments about app control and the running production jack update, but otherwise the article is as I first wrote it.

No material connection exists between me and Blue, Apple, TASCAM, Adobe, or any other vendor mentioned in this review. No one has offered any payments, freebies, or other blandishments in return for a mention or a favorable review.


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Adam Wilt

Adam Wilt

Adam Wilt has been working off and on in film and video for the past thirty years, while paying the bills writing software for animation, automation, broadcast graphics, and real-time control for companies including Abekas, Pinnacle, Omneon, CBS, and ABC. Since 1997 his website, adamwilt.com, has been a popular reference for information on the DV formats. He has reviewed cameras for DV Magazine and written its “Technical Difficulties” column, and taught classes and led panels at NAB, IBC, and DV Expo. He co-authored the book,”Optimizing Your Final Cut Pro System”, part of the Apple Pro Training series.