Mobile Phone Recording
Introduction
This document provides an overview of approaches to recording audio calls made on
smartphones. Options described include both paid and free software apps for phones running
the Android and iOS operating systems as well as a cross-platform hardware option. There are
certainly other software and hardware approaches beyond those mentioned here, and the
selection below serves as a curated overview of a handful of methods rather than an all-
inclusive survey.
Options are divided into two main sections, Software Options and Hardware Option. The
Software Options section is further divided into two subsections, one for each of the common
mobile phone operating systems, Android and iOS.
Things to know
When recording using a mobile phone the fidelity of the resulting recording is fundamentally
constrained by the limited sound frequency bandwidth of mobile phone audio transmission. In
addition, call fidelity is also impacted by the quality of the call connection and the capabilities of
the phone’s hardware. While recordings made between mobile phones can sound better than
those made between landline phones, they will not have the fidelity of recordings made in-
person using quality equipment, or remote recordings using some other available methods.
This stated, recording an interview using a mobile phone can be convenient and, for the
interviewee, requires no technical knowledge beyond familiarity with their own mobile or landline
telephone, no high speed internet connection, access to a computer, or any other additional
equipment.
As noted above, call connection will impact the quality of the resulting recording. If calling
mobile-to-mobile, try to determine that both parties have strong service at the time/location of
the call. If calling mobile-to-landline, the Interviewer should be sure service on their end of the
call is strong.
Software Options
The apps available for call recording depend on the operating system on the phone.
Android
Apps for mobile phones running the Android operating system are available via the Google Play store. There are a large number of
call recording apps for Android, and determining which are best--or which work with particular phone hardware/Android versions--is
difficult. In reviewing the options, we have relied on several online overviews of Android call recording apps, and we encourage those
interested in recording interviews with an Android phone to robustly--and critically--evaluate apps and their claims.
Google Voice
Automatic Call Recorder Pro
Cost
Free
Free version available, Pro version $6.99
Recorded file
format
32bit/11.025kHz monophonic MP3
AMR, AAC, MP4, WAV
File storage
Google Voice cloud storage; download to local storage via
Google Voice interface on a web browser
Local file storage with features to share to Google
Drive or Dropbox
Internet
connection
requirement
Only if using Google Voice web interface to receive a call
None
Pros
Free. Vast user base. Relatively easy to install, use, and
access recordings.
Option to record in 16bit/44.1kHz monophonic WAV
Cons
Low quality recordings. Can only record incoming calls.
Multitude of options and settings are challenging to
navigate; sound quality is poor (though not worse than
Google Voice) and caller/narrator is quieter on
recording
Additional
information
Google Voice seems to be the most widely used option
for Android users to record phone calls. Detailed
Automatic Call Recorder Pro by Appliqato seems to
be a popular option, though be sure you are
information on using Google Voice to record can be found
here: Record Calls on Android using Google Voice.
Google Voice records at a low sample rate of 11.025 kHz,
which results in noticeably low fidelity audio. The sound
quality is poor, the narrator is quieter on recording, and
the interviewer’s voice can cause distortion if too loud. To
record an interview using Google Voice the narrator is
required to dial into the interviewer’s Google Voice
number. The interviewer then initiates recording by
pressing “4” on the Google Voice dialpad.
Google Voice is also an option for use on iOS devices.
downloading the correct application in the Google
Play store as there are many copycats with the same
name and very similar logos. It is important to
experiment with this app, as the default settings do
not necessarily produce the best quality recording
possible. The app by default records all calls, so users
probably will want to turn this function off except when
recording an interview. The app records to the phone,
so users should confirm before an interview they have
enough storage space (especially if recording in
WAV).
iOS
Rev Call Recorder
Automatic Call Recorder Pro
Cost
Free
$3.99 monthly/$19.99 annually
Recorded file
format
32bit/22.05kHz monophonic MP3
32bit/8kHz monophonic MP3
File storage
In app; download via text/email, share to Dropbox and
Google Drive
In app; download via text/email, share to Dropbox or
Google Drive
Internet
connection
requirement
None
None
Required skills
Understanding iPhone Add Call/Merge Calls functions
Understanding iPhone Add Call/Merge Calls functions
Accessibility
Accomodations
Fee-based transcription of calls
Fee-based transcription of calls
Hardware
Requirements
Requires iOS 10.0 or later.
Requires iOS 10.0 or later.
Hardware
Recommendations
iPhone 6 or higher.
iPhone 6 or higher.
Pros
Free
Widely adopted
Cons
Lower quality recordings
Free version limited, paid version requires monthly fee.
Low quality recordings.
Additional
information
Rev Call Recorder is a free recording app for iPhone
produced by audio/video transcription company Rev. To
use Rev Call Recorder, one first dials Rev’s recording line
through the app, puts that call on hold, dials the
Interviewee, and then merges the calls. For those
unfamiliar with iPhone’s “Add Call” and “Merge Call”
features, it might be a bit overwhelming at first.
TapeACall is a popular, paid call recording app. The
app works via a merged call process where one first
calls TapeACall’s recording line, puts that call on hold,
dials the interviewee, and then merges the calls. The
limited sampling rate of 8kHz allows for capture of
sound frequencies up to 4,000 Hz, which is, curiously,
below the upper end of the sound frequency band
available on US mobile phone systems.
Hardware Option
JK Audio CellTap 4C
Cost
Free
Recorded file
format
Varies depending on settings of attached audio recording device
File storage
Varies depending on attached audio recording device.
Internet
connection
requirement
None
Required skills
Understanding of cell phone in/out connections and line-level input recording to external audio recorder.
Understanding of basic audio gain adjustments.
Hardware
Requirements
3.5mm input/output from phone, 3.5mm male-to-male cable, wired headset with microphone, stand-alone audio
recorder, appropriate cable to interconnect CellTap 4C and external audio recorder. If your phone does not have a
3.5mm jack, acompatible adapter is required.
Pros
Affordable, professional-quality interface. Records to external recording device.
Cons
Requires familiarity and comfort with a range of audio recording methods and technologies. Requires additional
hardware. Quality of recording still constrained by mobile phone audio transmission limitations.
Additional
information
Produced by JK Audio, a manufacturer of remote recording products, the CellTap 4C facilitates the use of an
external audio recording device to record mobile calls. Using wired connections, the CellTap 4C transits incoming
audio from the interviewee and outgoing audio from the interviewer both between the parties and to a connected,
stand-alone audio recorder. The user can set recording parameters on the recorder to their preference rather than
being limited by the set parameters of mobile phone recording apps. Each side of the call is recorded in a separate
channel of a stereo file, allowing for at least some degree of separation between voices.
It is important to note that the quality of the audio captured via the mobile phone connection will still be constrained
by the limitations of the sound frequency bandwidth of mobile phone audio transmission. As a result, the fidelity of
the interviewee’s audio channel will still be limited. In contrast, the interviewer’s voice--which is recorded
independently of the connected mobile phone--will sound clearer and more in line with an in-person recording. In
addition, the CellTap 4C requires wired connections between the phone and the CellTap 4C. Many newer mobile
phones, iPhones in particular, no longer come with wired 3.5mm jacks. To use the CellTap 4C with a phone that
does not have a 3.5mm jack, one needs to purchase a compatible adapter (in the case of the iPhone, a Lightning-
to-3.5mm connector) or purchase a compatible Bluetooth interface. Check with JK Audio for compatibility concerns
prior to purchasing any wired or Bluetooth adapters. The cable used to connect the CellTap 4C with a stand-alone
audio recorder will depend on the audio recorder’s input configuration.
