The Wildlife Acoustics Song Meter SM4 is the proven industry standard wildlife audio recording equipment, specially engineered to deliver quality sound recordings of birds, frogs, and other vocal animals in the wild.
With the ability to store terabytes of data and record birds and wildlife in the field for months at a time, the Song Meter SM4 gives scientists a flexible tool for conducting species inventory, presence/absence surveys, endangered species detection and habitat health monitoring.
High Quality Recordings
MAXIMIZE DETECTION AND FIDELITY.
The SM4 features two second-generation built-in microphones that create higher quality recordings of birds and vocalizing animals than previous generations of Song Meter microphones. The low-noise microphones have a superior signal-to-noise ratio so you capture more wildlife sounds that matter to you.
Dual-Channel Recording Capability
TWO CHANNELS FOR MORE RECORDING FLEXIBILITY.
Take advantage of the SM4’s dual-channel feature to ensure that recording continues – even after one microphone is disabled by wildlife-incurred damage. Record in stereo or mono using the built-in microphones, or connect one or two cabled microphones. Adding additional runs of cable to the external microphone gives you the ability to capture audio from far-off wildlife such as birds in the forest canopy or frogs at a nearby pond.
Easy-to-use Scheduling
CHOOSE A SCHEDULE OR CREATE YOUR OWN.
To get you started quickly, the SM4 features easy-to-use Quick Start schedules, such as sunrise to sunset. You can also customize your schedules for specific wildlife sound recording needs. The free SM4 Configurator software can be used to configure settings and schedules from a computer. The SM4 Configurator software also provides a Security Lock option to prevent accidental changes to deployment and recording settings.
Large Storage Capacity
CAPTURE TERABYTES OF DATA.
The SM4 has two SD card slots that accept SDHC and SDXC cards. When fitted with two 1TB cards, the SM4 can store up to two terabytes of data.
In addition, you can save card space by using W4V Compression. The format doubles the capacity of your SD cards with no noticeable degradation of recording quality. The resulting W4V files can be opened with and/or converted to uncompressed WAV files using the free version of Kaleidoscope software.
Features
- Industry-standard line of birds, frogs, and other vocal wildlife audio recorders, with over 20,000 SM4 family recorders sold to date
- Proven and reliable, with only 0.64% of recorders requiring in-warranty repairs
- 3-year warranty
- Weatherproof design suitable for any environment
- Compact, at 8.6” x 7.3” x 3.1” (218 mm x 186 mm x 78 mm)
- Built-in fail-safe and fault-tolerant technology, including two flash cards for failover and extensive internal diagnostics
- Two built-in, low-noise microphones allow for quality, stereo animal recordings
- Flexible gain settings and high-pass filters for optimal performance in different recording environments
- Record 510 hours scheduled over months using four D cell batteries, 305 hours using NiMH batteries or even longer using external power.
- Choose a quick-start schedule or easily create your own
- Strong anti-alias filters improve signal-to-noise ratios
- Capable of storing terabytes of data to two SDHC/SDXC flash cards
- Optional cabled microphones and hydrophones
- GPS attachment allows you to set date, time and location for multiple recorders
- Save card space via W4V compression, doubling the capacity of SD cards without degrading recording quality
- Compatible with Kaleidoscope Pro software to quickly scan recordings to help find species of interest
Recording Format
Two-channel, 16-bit PCM .wav files or compressed .w4v files
Sample Rates
The recorder supports the following sample rates in samples per second on one or two channels: 8000, 12000, 16000, 22050, 24000, 32000, 44100, 48000, 96000
Built-in Microphones (2)
Directional Characteristic: Omni-Directional
Sensitivity: -35 ±4 dB (0 dB=1V/pa@1kHz)
Signal to Noise Ratio: 80 dB Typ. at 1kHz (1 Pa, A weighted network)
Max Input Sound Level: 126 dB SPL Typ.
Run-Time
510 hours (typical at 24kHz stereo) with 4 D-cell Alkaline or 310 hours with NiHM batteries
Power Options
Internal power using 4 D-size alkaline or rechargeable NiHM batteries
External power via optional SM3/SM4 Power Cable
Storage
2 SDHC/SDXC flash card slots (Class 4 or greater)*
More than 1 terabyte total capacity using 2 512GB SDXC cards
Compression is available to further increase storage capacity
*We recommend using SanDisk SDHC/SDXC cards.
Dimensions Height: 8.6" / 218 mm Width: 7.32" / 186 mm Depth: 3.1" / 78 mm
Enclosure Material - Polycarbonate
Enclosure Environmental Protection Fully weatherproof with integrated humidity control
Operating Temperature -4°F to +185°F or -20°C to 85°C
Warranty 3 years
BUILT-IN MICROPHONES OR SMM-A2 ACOUSTIC EXTERNAL MICROPHONE
| Sensitivity built-in | -35 ±4 dB (0 dB=1V/pa@1kHz) |
| Sensitivity SMM-A2 | -9 ±4 dB (0 dB=1V/pa@1kHz) |
| Signal-to-Noise Ratio | 80dB typical at 1kHz (1 Pa, A weighted network) |
| Dynamic Range with Preamplifier | 14dB - 100dB SPL at 0dB gain |
| Dynamic Range without Preamplifier | 39dB - 126dB SPL at 0dB gain |
Which of our Song Meter wildlife recorders is right for your research?
Understanding Wildlife Audio Recorder Specifications
The Signal to Noise Ratio (SNR) is a measure (as a ratio expressed in dB) of a reference signal against the background noise. This is typically relative to a 1 Pascal (= 94dB SPL) signal at 1kHz as compared to the recording system (microphone and electronics) self-noise.
A higher SNR implies that the recorder can detect quieter signals at a greater distance before the signal is lost in the noise.
Every additional 6dB of SNR doubles the distance at which a signal can be detected, assuming no environmental background noise such as wind, rain, road noise, or airplanes.
A recorder may have higher or lower relative SNR at different frequencies. The SNR Chart below can be used to assess the signal-to-noise ratio and its impact on recording the frequencies of specific species. For example, the Micro has a particularly good SNR at just under 6,000 Hz so it would record better around that frequency.
In the Song Meter family, the SM4 has the best overall SNR followed closely by the Mini, and then the Micro.
The Frequency Response curve shows the sensitivity and noise of a recorder across its frequency range. The flatter a frequency response curve, the more accurately a recording represents the signals recorded. Frequencies at peaks or troughs in a curve will be relatively over or under recorded, giving a louder or quieter signal.
Note that frequency response can be affected by other factors such as the angle of the sounds as they hit the microphone and interference from trees or other structures to which the recorder is mounted.
The Sensitivity Chart below can be used to assess frequency responses for the Song Meter family. The SM4 has the flattest frequency response followed by the Mini, and then the Micro
A High-Pass Filter (HPF) reduces the amplitude of lower frequency signals (like those caused by wind, rain, vehicles, or airplanes) while allowing frequencies above a certain frequency to pass though. This can reduce audio distortion in the recordings caused by lower frequency sounds that are too loud for the microphone to handle.
In the Song Meter family, the SM4 offers the greatest flexibility, with a high-pass filter that can be set independently on each of its two channels to optimize for different conditions and species of interest. It can be set to off (no high pass filter), 220Hz, or 1000Hz. The Mini and Micro have a fixed 100Hz high-pass filter, meaning that it filters out sounds below 100Hz. Therefore, if you are recording in the infrasonic range, the SM4 may be a better solution since the high-pass filter can be turned off.
An Anti-Alias Filter reduces aliased signals in the recording. Aliasing is an audio artifact that occurs when high frequency sounds are recorded that are above half the chosen sample rate. When this happens, part of the higher signal appears in the recording as unwanted noise. You can see a visual example of this here.
In the Song Meter family, the SM4 offers the strongest anti-alias filter, reaching 55dB of signal reduction at 60% of the sample rate. The Mini has a weaker anti-alias filter reaching only 12dB of signal reduction at 60% of the sample rate. The Micro has the weakest anti-alias filter reaching only 6dB of signal reduction at 60% of the sample rate.
Adjustable Gain allows flexibility to choose the optimum setting for any deployment. Gain makes a signal louder when it is being recorded. However, too much gain can cause loud signals to clip, resulting in distortion and too little gain may result in a poor resolution and a lower quality recording.
The SM4 offers the greatest flexibility with a 26dB gain pre-amplifier and additional gain of up to 59.5dB in 0.5dB increments. The Mini and Micro offer 4 gain settings in 6dB increments between 6 and 24dB
