8. SD Card Contents
This section describes what kinds of files the Song Meter Mini 2 saves to its SD card, how they are organized, and what kinds of information they contain.
SD Card Volume Name
Beginning in firmware version 4.4, formatting an SD card using the Song Meter Mini 2 renames the card to the first 11 characters of the recorder name.
A card can still be used even if it has a different name. If you reformat the card using the SD Association's formatting tool, you can assign a custom name during the formatting process, or you can use your computer to rename the card after formatting.
File Name Conventions
Files saved by the Song Meter Mini 2 use file names that identify which recorder produced each file and when the file was saved.
Recorder Name
Audio files, summary files, diagnostics files, and exported configuration files begin with the Recorder Name. By default, the Recorder Name is the recorder's serial number, but this can be changed in the Configuration Editor when paired with a recorder.
Date and Time
The names of audio files and diagnostics files include the date and time of day when each file was produced, according the time zone that was set on the recorder for that deployment. For audio files, this marks the date and time of day when the audio file began. The format used is YYYYMMDD_hhmmss.
For example, an audio file named WALDEN_20240601_140505.wav was saved by a recorder with the name WALDEN, and it began recording on June 1, 2024 at 14:05:05, or five seconds after 2:05 PM.
SD Card Organization
The Song Meter Mini 2 saves all non-audio files to the top level of the SD card, meaning they are not placed into a folder within the card. These non-audio files include:
Summary file (
[RECORDER NAME]_Summary.txt).Diagnostics files (
[RECORDER NAME]_[DATE]_[TIME].minidiags).Configuration files (
[RECORDER NAME].miniconfig).
All audio files are saved to a folder named Data.
Audio Files
This section covers the types of audio recordings the Song Meter Mini 2 saves to its SD card and what metadata is included in those recordings.
Full-Spectrum Recording Files
Acoustic recordings are saved as .wav files. This is an uncompressed audio format that is widely supported across many kinds of audio playback and analysis software. We refer to this kind of audio recording as full-spectrum to distinguish it from more limited and specialized forms of recorded audio data that are sometimes used when recording ultrasound.
Full-spectrum files record audio of all frequencies up to half the sample rate. Most commonplace audio files, like music or voice recordings, are full-spectrum files. If you open a full-spectrum file in Kaleidoscope Pro or another spectrogram viewer, you can see all components of the audio file across the recorded frequency spectrum.
WAV File Metadata
Metadata is additional information embedded into each recording alongside the recorded audio. The Song Meter Mini 2 saves metadata in the open GUANO format. Software that supports the GUANO format can view these metadata fields. Kaleidoscope Pro Sound Analysis Software can display these fields with or without a paid license. See GUANO Metadata Fields for a list of metadata fields included in this format.
Additional Metadata
Full-spectrum .wav files include additional metadata not shown in the GUANO fields. If you open a .wav recording from a Song Meter Mini 2 in the desktop Mini/Micro configurator, the program will display all of the settings and schedule parameters that were programmed on the recorder that produced the recording.
Compressing Full-Spectrum WAV Files
Using the Kaleidoscope Pro Sound Analysis Software, you can compress the size of .wav files using a special format called W4V. W4V is a compression format developed by Wildlife Acoustics specifically for bioacoustics recordings. It is designed to reduce file size without changing any vital content of the recording that might be used for species identification or similar analysis tasks. Depending on the compression settings, file sizes can be reduced by 50-75%. W4V-compressed files are saved with a .w4v extension.
The drawback of this format is that the noise floor of the recording is increased. Depending on the background noise level of the original recording, this increased noise floor may have not a practical effect on your analysis or even be discernible. However, it is not recommended for applications involving precision measurement of ambient noise levels.
Kaleidoscope Pro can be used with or without a paid license to convert in both directions between .wav and .w4v files. Note that the increased noise levels produced by W4V compression will remain if the file is converted back to .wav format.
GUANO Metadata Fields
Full-spectrum .wav files saved by the Song Meter Mini 2 include the following GUANO fields:
Firmware version: Firmware version installed on the recorder at the time of recording.
Length: Duration of the audio file in seconds.
Loc Position: Latitude and longitude saved to the recorder at the time of recording.
Make: Manufacturer of the recorder (Wildlife Acoustics, Inc.).
Model: Model name of the recorder.
Original Filename: File name of the recording as originally saved to the SD card by the Song Meter Mini 2. This metadata field will remain even if the file name is later edited.
Samplerate: Sample rate of the recording in hertz (see Sample Rate).
Serial: Serial number of the recorder.
Temperature Int: Reading from the recorder's internal temperature sensor in degrees Celsius at the time of the recording.
Timestamp: Date and time at which the recording started. This field also saves the UTC offset that had been set in the recorder's Location & Time Zone Screen.
WA|Song Meter|Audio settings: Array of audio settings used by the recorder:
rate: Duplicate of the Samplerate metadata value.
gain: Gain setting used by the recorder, in decibels, as set in the recorder's Acoustic Settings Screen.
WA|Song Meter|Prefix: The custom Recorder Name for the Song Meter Mini 2.
Summary File
Whenever the Song Meter Mini 2 runs a recording schedule, it records a running log of basic status information to a summary text file on its SD card. This file's name is formatted as [RECORDER NAME]_Summary.txt.
A new line is written to the summary file for every minute the Song Meter Mini 2 is awake and recording. Each line of text is broken up by commas into data fields, with column headers listed in the first line of the file. The summary file can be converted into a Comma Separated Values (.csv) file and imported into a spreadsheet processor.
Tip
Throughout a summary file, you may see the header row (normally the first row in the file) repeat. Each instance of the header row indicates that the recorder powered on and began running its schedule. This can occur if the recorder is manually turned off and on again, if the batteries momentarily fail as they reach the end of their life, or if the recorder reboots in response to some other problem.
Summary File Columns
The summary file includes the following data, organized into columns separated by commas:
DATE | Indicates the date when each line was written to the summary file. |
TIME | Indicates the time of day when each line was written to the summary file. |
LAT | Indicates the numerical value of the latitude coordinate saved in the recorder's Location & Time Zone Screen. |
NS | Indicates whether the latitude coordinate is north or south of the equator. A value of N indicates a northern latitude, and a value of S indicates a southern latitude. |
LON | Indicates the numerical value of the longitude coordinate saved in the recorder's Location & Time Zone Screen. |
EW | Indicates whether the longitude coordinate is east or west of the prime meridian. A value of E indicates an eastern longitude, and a value of W indicates a western longitude. |
POWER(V) | Indicates the measured voltage of the Song Meter Mini 2 's batteries, in volts. |
TEMP(C) | Indicates the temperature measured by the Song Meter Mini 2 's internal temperature sensor, in degrees Celsius. Because this sensor is located inside the recorder's enclosure, its reading can deviate significantly from the ambient temperature. |
#FSFILES | Indicates the number of full-spectrum .wav files that finished recording during the preceding minute. |
#ZCFILES | Used only by the Song Meter Mini Bat and Song Meter Mini Bat 2. |
#SCRUBBED | Used only by the Song Meter Mini Bat and Song Meter Mini Bat 2. |
Diagnostics Files
Diagnostics file are named with the format [RECORDER NAME]_[DATE]_[TIME].minidiags. These files save a copy of the recorder's settings, as well as additional status information and a record of what the recorder was doing before the diagnostics file was generated.
Most of this information is only visible using special tools support staff and engineers at Wildlife Acoustics use during troubleshooting, but you can view the settings that were used by the recorder by opening a .minidiags file in the desktop Mini / Micro Configurator Software.
Diagnostics files can be saved to the recorder's SD card or generated by the Song Meter Configurator app under a few different circumstances.
Manual Diagnostics Generation
A diagnostics file can be manually saved to the SD card using the on the main panel of the Song Meter Mini 2. See Export Diagnostics File to an SD Card Using the Recorder's Physical Controls for instructions on this procedure.
It is also possible to export a diagnostics file from the Song Meter Configurator app directly to an outgoing email, without saving the file to the SD card. See Email Diagnostics File to Wildlife Acoustics for full instructions.
It is generally not necessary to manually export a diagnostics file unless a Wildlife Acoustics Support representative requests one. For some kinds of troubleshooting, a diagnostics file can help identify certain issues, but a diagnostics file is generally only useful once support understands the broader context around any issues you may be seeing.
Automatic Diagnostics Generation
If the Song Meter Mini 2 experiences a sudden reboot, it will save a diagnostics file to the SD card as soon as it powers on. The date and time in the file name of the .minidiags file indicate the time when the file was generated.
Reboots and the diagnostics files they produce can sometimes indicate a persistent issue with the Song Meter Mini 2. However, there are several mundane and common causes for automatic diagnostics files that do not necessarily indicate a persistent issue with your recorder, including:
Manual force-reboot
If you pull the batteries from the recorder without switching the switch to , then quickly reinsert them, the Song Meter Mini 2 will interpret this as an unexpected reboot and generate a diagnostics file.
Dying batteries
If the batteries are used to the full extent of their lifespans, they may reach a point where they are just barely keeping the Song Meter Mini 2 powered on. At this point, small fluctuations in power draw can cause the battery voltage to drop, causing the recorder to power off unexpectedly.
The Song Meter Mini 2 will attempt to shut itself down cleanly before the batteries reach this point, but that shutdown is based on the typical behavior of 18650 Li-ion batteries and alkaline AA batteries. If you use alternative battery types, like NiMH or Energizer® Ultimate LithiumTM AA batteries, the recorder will be more likely to generate diagnostics files at the very end of the batteries' life.
Analyzing Your Recordings
The recordings produced by the Song Meter Mini 2 are compatible with Wildlife Acoustics' Kaleidoscope Pro Sound Analysis Software and with a broad range of other audio analysis, processing, and editing software.
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Kaleidoscope Lite
Kaleidoscope Lite is the free version of our professional sound analysis software, Kaleidoscope Pro. In Kaleidoscope Lite, you can perform many useful functions with your recordings.
Separate distinct sounds from periods of silence. Generate a table of sound occurrences and add notes on each sound entry.
Visualize your recordings as spectrograms.
Listen to your recordings with options for altered playback pitch and bandpass filtering.
Convert recordings between formats.
Kaleidoscope Lite and Kaleidoscope Pro are the same piece of software, which can be downloaded for free from our website: wildlifeacoustics.com/account/downloads. By default, only the Kaleidoscope Lite features are enabled, and you can use the software for as long as you would like. You can find video tutorials on the features available in Kaleidoscope LIte on our website.
Kaleidoscope Pro
Kaleidoscope Pro Sound Analysis Software allows you to quickly sort, label, and identify bird songs, frog calls, bat echolocations, and more from weeks, months, or even years of recordings. Whether you are conducting species inventory, presence/absence surveys, endangered species detection or habitat health monitoring, Kaleidoscope Pro significantly minimizes the time it takes to find what you’re looking for. Download it from our website's Downloads page and request a two-week trial of the full set of features from the Kaleidoscope Pro Trial page.
Third-Party Software
The Song Meter Mini 2 creates standard .wav files that can be opened with most audio editing and analysis applications. The audio application must be able to support the sample rate of the recorded file.