Radio Magazine - January 2013 - (Page 36)
Mics for Smartphones
by Chriss Scherer, editor
he smartphone has become everyone’s multi-tool. Recording and
editing audio on one is common. But
does the on-board mic provide the
quality you really want? Reports to Radio magazine
say the mics (there are three) on the iPhone 5 are
good enough to be used on air. But if you don’t like
the on-board mic what can you do?
There are two basic options: Connect to the
docking port (at least up to the iPhone 4) or use
the TRRS mic/headphone jack. We found docking
adapters for the iPhone, but with the redesigned
connector on the iPhone 5, some of these devices
are useless. There are adapters to connect 4 and
earlier jacks to the 5. And if you’re not using an
iPhone, your only real option is the TRRS jack.
For iPhone version 4 and earlier, there are
stereo mics that clip to the connector, including
the Tascam Ixz, Logitec LIC-iREC03P and Blue
Mics Mikey. There are also adapter housings
that provide mic jacks, including the Fostex
AR-4i and Tieline MicAdapter.
The iPhone connector allowed a stereo connection, but the TRRS jack is a mono input. It appears
IK Multimedia iRig Mic Cast
iRig Mic Cast is an ultra-compact portable voice
recording microphone. It features a tight unidirectional pickup pattern that minimizes background
noise making it ideal for single-source audio recording. In addition to an incredibly flat frequency response with zero tonal coloration, the iRig Mic Cast
features a stereo mini-jack headphone output, mini-switch for
two sensitivity settings, adjustable desktop stand, bumper-friendly mini-jack connector, and iRig Recorder and VocaLive apps.
the TRRS jack is common regardless of the phone’s
manufacturer. With that in mind, we looked at
ways to connect to the jack.
The 3.5mm jack has four connections: left and
right audio out, mic in and a ground return. The
extra ring on a TRRS shifts the ground from the
sleeve to the second ring and uses the sleeve for the
We found two options to connect a mic to the
jack: a plug-in mic that sticks out of the phone
or an adapter cable to connect a mic and sometimes a headset.
IK Multimedia IK iRig Pre
This microphone preamp allows any mic with an XLR
connector to be connected to a smartphone. The adjustable thumb wheel gain control sets the level. The
onboard 9V battery provides voltage for phantompowered condenser microphones for at least for 15
hours of continuous use. The 3.5mm stereo headphone output allows for monitoring. A Velcro strip
slot allows the unit to be mounted on a mic stand or
other convenient spot.
Vericorder XLR with Preamplifier
The i456 is a wide cardioid microphone for general purpose audio
recording. The mic is 5.6cm long and has a frequency response of 20Hz to
20kHz. The source impedance is less than 2.2kΩ. The cardioid pattern has
a sensitivity of -50dB. The electret mic is powered by the phone’s jack. The
company also manufactures the i436 precision mic, the i266 high-sensitivity mic and the iShotgun.
This adapter breaks out the 3.5mm TRRS phone
jack to an XLR input and 3.5mm TRS headphone
jack. The adapter includes a preamplifier with 6.1dB
gain that is powered by the smartphone. Frequency
response is 20Hz to 20kHz. The mic cable is about 2’
long. The company also makes the Mini Mic, which
plugs directly in the TRRS jack.
The TRRS plug connections are shown at right. Making an adapter cable
is not difficult if you can find the plug. A basic adapter can be made to
simply connect a mic with a TRRS to TRS or TRRS to XLR cable. Adding
the TRS headphone jack is an option.
Many apps will not provide a confidence recording output when the mic
is in use. Having the headphone jack saves you from having to unplug the
mic and connect headphones between takes.
Some notes on the TRRS connector. In our research, we saw some
reports that an iPhone may not always detect the attached mic when a
J a n u a r y 2 0 1 3 | r a dioma gon lin e .c om
home-built adapter is used. One website
suggested adding a 1kΩ resistor across
pins 2 and 3 of the XLR connector.
There is a bias voltage on the
TRRS jack. We also saw references
to placing a capacitor in series with
the mic connection, but we saw just
as many posts saying it wasn’t necessary
because a dynamic mic will ignore the
gr t ea
Roll your own
Table of Contents for the Digital Edition of Radio Magazine - January 2013
Radio - January 2013
Table of Contents
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Side By Side
Radio Magazine - January 2013