SM4 Acoustic Wildlife Acoustics - With 2 built-in microphones

The two built-in microphones are part of a new generation of sensors, offering superior recording quality compared to their predecessors.

In addition to the two integrated microphones, the SM4 also includes two extra microphone inputs, providing greater flexibility. Optional accessories such as a hydrophone cable or SMM-A1/SMM-A2 microphone can easily be connected.

You can record in mono or stereo, and add additional extension cables (up to 50 meters) to capture wildlife in challenging environments such as forests or ponds.

The new low-power processor ensures a maximum operating time of 450 hours. In sleep mode with scheduled recordings, the unit can remain deployed for several months, reducing the need for unnecessary field visits.

The redesigned menu now features a “Quick Start” mode, making operation more intuitive and offering several preprogrammed configurations. Simply select the most suitable option for your situation and press the “Start” button.

Of course, the SM4 can also be fully customized for advanced users who wish to fine-tune recording parameters.

As with the SM4BAT, the SM4 includes two SDHC/SDXC memory card slots (up to 1 TB) and an integrated headphone jack that allows real-time bioacoustic monitoring. An optional GPS module is available to date and geolocate recordings.

Its polycarbonate housing is designed for use in extreme conditions such as humid jungles or deserts. Wildlife Acoustics offers a 3-year manufacturer’s warranty.

Complete Pack Includes:

• 1 SM4 recorder
• 2 Kingston SDXC 64 GB cards
• 4 Ansmann D-size 10,000 mAh rechargeable batteries (must be charged before use)
• 1 Masterlock brass combination padlock for securing the SM4BAT
• 1 Masterlock Python cable with keys for fixing the SM4BAT to a tree or other structure

Important: The complete SM4 Acoustic Pack does not include a protective enclosure, as it would block the two integrated microphones from recording properly.

Technical Specifications

• Recording technology: Two channels, 16-bit .wav or compressed .w4v files
• Sampling rates: Supported sample rates (in samples per second, single or dual channel): 8,000 / 12,000 / 16,000 / 22,050 / 24,000 / 32,000 / 44,100 / 48,000 / 96,000
• Integrated microphones: Omni-directional (x2)
• Sensitivity: -35 dB ± 4 dB at 1 kHz (0 dB = 1V/PA)
• Signal-to-noise ratio: 80 dB typical at 1 kHz (1 Pa, A-weighted)
• Maximum input sound level: 126 dB SPL (typical)
• Autonomy: Up to 510 hours depending on activity level, weather conditions, and battery quality
• Power options: Internal power with 4 batteries/rechargeables (NiMH strongly recommended) or external via optional SM3/SM4 power cable
• Memory: Dual SDHC/SDXC slots, maximum total capacity 1 TB
• Dimensions: Height 21.8 cm / Width 15 cm / Depth 7.1 cm
• Weight: 640 g (without batteries), 1.2 kg (with batteries)
• Housing material: Polycarbonate
• Operating temperature: -20° to +85°C
• Weatherproof: Fully weather-resistant with built-in humidity control
• Warranty: 3 years

A comparative table of the Wildlife Acoustics SM4, SM Mini 2, and SM Micro 2 recorders can be found at this link:

https://www.wildlifeacoustics.com/products/song-meter-sm4-vs-mini2-vs-micro-2

Typical Uses of the SM4

• Wildlife inventory: Multi-point recordings to identify birds, amphibians, or mammals after analysis.
• Citizen science: Participation in projects such as “Vol de Nuit” (nocmig) for tracking nocturnal bird migration.
• Ecological monitoring: Long-term observation of natural sites or evaluation of habitat changes and project impacts.
• Soundscape analysis: Study of acoustic biodiversity and anthropogenic noise sources.
• Rare species monitoring: Detection of nocturnal or elusive species (owls, amphibians).
• Educational use: School projects, nature workshops, and awareness activities about acoustic ecology.
• Automated analysis: Data processing with software such as Kaleidoscope for large-scale sound datasets.