Click here to download and try the fully functional Multi-Instrument software using your sound card as the ADC and DAC device!
VT USA-268A and VT USA-268B are PC-based real-time underwater sound analyzers with ultra-low noise and a huge dynamic range, covering 9 Hz to 92 kHz (-3 dB), powered by the comprehensive virtual instrument software Multi-Instrument®. Each analyzer includes a high-sensitivity hydrophone with a built-in preamp and an XLR output connector, plus an XLR-to-USB audio interface. The hydrophones can withstand a static water pressure up to 350 m and drive cables up to 250 m with negligible signal degradation.
The hydrophones in the two analyzers are manufactured with the same industrial-grade sensors under strict quality control, making them well-suited for absolute underwater sound level measurements in marine and industrial environments. The hydrophone of VT USA-268A is assembled with a 150g sliding stainless steel weight on its cable to provide negative buoyancy and stable positioning in mild wind and current conditions. The hydrophone of VT USA-268B features a standard panel-mount design, making it well suited for integration into systems, such as autonomous recording units, autonomous or remotely operated vehicles, and dive camera enclosures.
The XLR-to-USB audio interface used in the analyzers has two ADCs working in tandem to create a single output data stream in 32-bit float format. One “low gain” ADC is optimized for high-level signals, and the other “high gain” ADC is optimized for low-level signals. This state of the art dual-ADC architecture provides an unmatchable dynamic range compared with the conventional single ADC approach. It is possible to capture underwater sounds at low levels with high fidelity and at high levels without clipping, all without the hassle of manual analog gain adjustment.
Find out more: Manual
| General | USA-268A | USA-268B |
|---|---|---|
| Hydrophone with a Built-in Preamp |
 Default Cable Length: 10 m |
 Default Cable Length: 10 m |
| XLR-to-USB Audio Interface |
|
|
| General | USA-268A | USA-268B |
|---|---|---|
| Frequency Range (-3dB) | 9Hz ~ 92kHz | |
| Sound Level Measurement Range | 50dB ~ 185dB (typical) | |
| Operating Depth | <200m | |
| Sampling Rate | 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz | |
| Bit Depth | 32-bit Float / 24 bit | |
| Number of Input Channels | 2 | |
| Number of Output Channels | 2 | |
| Direct Monitoring without Passing Through Computer | Supported | |
| Frequency Accuracy | 0.001% | |
| Frequency Weighting | Flat, A, B, C, ITU-R 468 | |
| Time Weighting |
Linear, Exponential (Equivalent continuous sound level (Leq) fully complies with IEC61672) |
|
| Octave Analysis |
1/1,1/3,1/6,1/12,1/24,1/48, 1/96 (Complies with IEC61260) |
|
| Other Functions | Much more functions are described in the software manual. | |
| USB interface | USB 2.0, driver installation required | |
| Input Isolation | No (Isolation can be achieved through a USB high speed isolator) | |
| Power Source | USB bus power (Type C), DC 5V power supply (Type C) | |
| Power Consumption | Max. 2.5W | |
| System Requirements |
Windows 10/11, 32 bit or 64 bit. Minimum Screen Resolution: 1024 x 600 |
|
| Calibration Accuracy | ± 2dB | |
| General | USA-268A | USA-268B |
|---|---|---|
| Transducer Type | Thin-wall PZT | |
| Frequency Range (-3dB) | 4.3Hz ~ 110kHz | |
| Sensitivity | -180dB re: 1 V/μPa (i.e. 0.001V/Pa) | |
| Horizontal Directivity | +0.2/-1 dB @50kHz | |
| Vertical Directivity | +0/-5.9 dB @50kHz | |
| Survival Depth | 350 m | |
| Operating Temperature Range | -10℃~+80℃ | |
| Acoustic Overload Pressure | 188 dB | |
| Size | ϕ12mm x 43mm | |
| Weight (hydrophone only) | 8g | |
| Specific Gravity (hydrophone only) | 1.4 | |
| Wetted Materials | Polyurethane, anodized aluminum | |
| Added Weight | 150g | No |
| With Built-In Preamp | Yes | |
| Connector | XLR (pin 1: ground, pin 2: hot, pin 3: cold) | |
| Power Supply | 48V Phantom | |
| Input | Input Impedance | Max. Voltage | Dynamic Range | XLR Phantom Power |
|---|---|---|---|---|
|
Left (Input 1): XLR/TRS/TS(HiZ) Combo Jack |
XLR: 2.7 kΩ TRS: 4 kΩ / 1MΩ (when HiZ on) |
XLR: 2.35 Vp TRS: 23.0 Vp / 4.30 Vp (when HiZ on) |
XLR: 134 dB TRS: 129 dB TS(HiZ): 123dB |
48V |
|
Right (Input 2): XLR/TRS Combo Jack |
| Output | Output Impedance | Max. Voltage |
|---|---|---|
| Left (Output 1): TRS (balanced) Jack | 100 Ω | 9.0 Vp (adjustable through volume knob) |
| Right (Output 2): TRS (balanced) Jack | ||
| Headphone | 12Ω | 4.4 Vp (adjustable through volume knob) |
| General | |
|---|---|
| MIDI | IN/OUT (5-pin DIN connectors) |
| Input Frequency Response |
44.1 kHz: 20Hz~20kHz, +0.1 dB / -0.2 dB -3dB: 9Hz~21.8kHz 48 kHz: 20Hz~20kHz, ±0.21dB -3dB: 9Hz~23.8kHz 96 kHz: 20Hz~40kHz, ±0.22dB -3dB: 9Hz~47.6kHz 192 kHz: 20Hz~80kHz, +0.1 dB / -0.2 dB -3dB: 9Hz~91.8kHz |
| TRS Output Frequency Response | 44.1 kHz: 20Hz~20kHz, +0.0 dB / -0.1 dB -3dB: 1.9Hz~21.1kHz 48 kHz: 20Hz~20kHz, ±0.1dB -3dB: 1.9Hz~22.8kHz 96 kHz: 20Hz~40kHz, ±0.1dB -3dB: 2.1Hz~45.6kHz 192 kHz: 20Hz~80kHz, +0.0 dB / -1.0 dB -3dB: 2.1Hz~93.2kHz |
| Headphone Output Frequency Response |
44.1 kHz: 20Hz~20kHz, +0.0 dB / -0.5 dB -3dB: 1.5Hz~20.9kHz 48 kHz: 20Hz~20kHz, ±0.3dB -3dB: 1.5Hz~22.8kHz 96 kHz: 20Hz~40kHz, ±0.1dB -3dB: 1.6Hz~45.6kHz 192 kHz: 20Hz~80kHz, +0.0 dB / -1.0 dB -3dB: 1.7Hz~95.2kHz |
| USB Connector | Type C |
| Power Consumption | Max. 2.5W |
| Dimension | 164 mm (W) x 105.5 mm (D) x 65 mm (H) |
| Weight | 355g |
