Frequently Asked Questions

The TR-ORCA is a broadband underwater acoustic recorder and signal processor that supports up to five hydrophone channels and extremely high sampling rates, so users can capture the entire underwater soundscape digitally, with exceptional quality. This device can be used as an autonomous acoustic recorder to record raw or processed underwater sound data. It can also act as a real time multichannel digital hydrophone, streaming acoustic data to the user in raw format and as real time spectrograms and third octave plots. The TR-ORCA does internal processing and can log or stream this data to the user, so the user can save countless hours of post-analysis effort.

The TR-ORCA comes in a number of packages. The base package is small and light, so it can easily be deployed by a single person from a vessel or diver. This device comes with an internal rechargeable battery to last for 24 hours at worst case conditions (maximum sampling rates, and disk usage, continuous), 500 GB of high speed memory is included, as well an additional 256 GB of low power memory, which can be used at low sample rates. It also comes in packages with large internal battery packs. All versions of our TR-ORCA have an external power input, so many types of external power sources can be integrated with the product.

Passive Acoustic Monitoring: TRAC softwareThe purchase of our base TR-ORCA package includes everything to get you capturing, recording and streaming live, high quality underwater acoustic data. The base package includes:

  • TR-ORCA multichannel broadband underwater acoustic recorder and signal processor
  • One low noise 150 kHz bandwidth hydrophone element (additional available for purchase)
  • 500 GB Internal SSD memory, 256 GB of SD card memory
  • High Speed USB Download Cable
  • 20m of Ethernet cable suitable for short term subsea use
  • Real time configuration and streaming data software TRAC, free with purchase
  • Carrying case

The TR-ORCA is more than a simple hydrophone, and more than a simple acoustic recorder. This device not only records and streams raw acoustic data, it also processes this data and makes sense of it for the user. 

With Turbulent Research’ free TRAC software, users can easily setup their instrument parameters including enabled channels, sampling rates, channel gain, recording schedules, calibration and internal processing. Additionally, TRAC provides a real time portal to the user’s instrument. Digital multichannel acoustic data is presented as real time spectrograms, FFTs, time domain plots of particular frequency bins, third octave plots with percentiles, and live, real time audio. TRAC is a free application supplied with the purchase of all Turbulent Research passive acoustic products.

Below is a few screenshots of our TRAC application:

Control, Real time spectrograms, time series plots, live underwater audio, 1/3 Octaves, Stats


The TR-ORCA can be used with only one channel enabled, but also gives the user flexibility to use multiple hydrophones in the future. Multiple synchronous hydrophones means that the user can do simple single channel studies, but also do more complex investigations related to source localization, particle velocity, sampling complex acoustic environments by sampling at multiple depths, or maximize dynamic range by using different sensitivity hydrophones at the same time.

The TR-ORCA includes one hydrophone when purchased, and our pricing is competitive with any single channel acoustic recording system in the world. By starting with a base package of the TR-ORCA with one channel, users can upgrade down the road by simply purchasing additional hydrophones when the need arises.

The bandwidth in an acoustic acquisition system is limited by the hydrophone bandwidth, the analog input bandwidth and the sampling rate of the system. By default we use hydrophones that have a bandwidth exceeding 150 kHz, and an analog bandwidth out to about 160 kHz. We use a fixed sampling rate of 768 kHz on our analog to digital converters so this entire bandwidth is adequately sampled. Changes in sample rates are done in the digital domain using digital filtering and decimation techniques.

Typical bandwidth is therefore out to about 150 kHz when using the 384 kHz sampling rate mode. This wide bandwidth allows the user to capture not only audible underwater noise, but sources well into the ultrasonic spectrum, including dolphin and porpoise clicks, sonar signals from vessels and a variety of commercial fish tags.

Turbulent Research was founded with a core value of providing value to our customers. As an early stage company in the oceans technology space, we recognize how much of a barrier the high price of oceanographic equipment can be to good science or using the right technology for the job. For that reason we have priced our products as fairly as possible.

We feel our systems provide the most value of any passive acoustic system in the world, with no compromise on overall performance and capability. Please contact Turbulent Research or one of our worldwide sales agents to get a fast quote for your application.

Users can absolutely record, stream and process high quality acoustic data all at the same time. The TR-ORCA has been designed to give users maximum flexibility, and provide many valuable use cases for a variety of end users. The TR-ORCA was designed to be a low power acoustic recorder, but also as a broadband digital hydrophone system. This flexibility does come with some limitations in terms of what can be done simultaneously.  The table below shows some common use cases.

Passive Acoustic Monitoring: Autonomous RecorderPassive Acoustic Monitoring: Realtime Multichannel Digital HydrophonePassive Acoustic Monitoring: Autonomous RecorderPassive Acoustic Monitoring: Realtime Multichannel Digital HydrophonePassive Acoustic Monitoring: Realtime Multichannel Digital Hydrophone

Hydrophones connect to the TR-ORCA through five standard 8 pin micro-circular series wet mate female connectors. Users can choose to populate all five hydrophone channels or use just one. We supply hydrophones that can easily integrate with the TR-ORCA, and can be directly connected to the end cap with a locking sleeve. Additionally, they can be cabled on up to 100m of underwater cable, giving the user maximum flexibility in their deployments. Though we do recommend hydrophones supplied by Turbulent Research, it is possible to interface to other hydrophones as well. The TR-ORCA provides a nominal output voltage that can be used to power external, pre-amplified hydrophones, which is a common use case. By default hydrophone inputs are single ended, but if you wish to use balanced or differential inputs, we can accommodate you. Please contact us for technical information.

Hydrophones supplied by Turbulent Research are calibrated at the factory in water and in air at low frequencies. We provide calibration data in a readable excel format, and also in a file that can be loaded directly into your TR-ORCA. All TR-ORCA units supplied with hydrophones that store the calibration data internally to the device from the factory. If you wish to recalibrate, or use custom hydrophones you can easily enter in calibration data using our TRAC application.

Hydrophone Calibration

The TR-ORCA offers exceptional acoustic data quality. The plot below shows the self-noise floor of the TR-ORCA using hydrophones supplied with the base TR-ORCA package.

Passive Acoustic Monitoring: self-noise floor

The standard package comes with 500 GB of SSD memory, and 256 GB of SD Card memory. These memories are used in different circumstances and offer differing levels of performance and power consumption. More than 4 TB of total memory can be supplied with the TR-ORCA on request.

The base TR-ORCA package is designed for relatively short deployments, where broadband and exceptional data quality are required. TR-ORCA also shines in any real time scenario, where data can be recorded directly to the user’s computer using our TRAC application. Adding an external, or internal extended battery pack can prolong any deployment a great deal. The TR-ORCA accepts many types of external power sources. Processing schemes and scheduling schemes can be setup in TRAC to increase the deployment length as well. The table below represents some worst case continuous recording scenarios.

Passive Acoustic Monitoring: battery life and memory

The TR-ORCA is especially useful in the characterization of ambient and anthropogenic underwater noise. This device can record and stream raw samples, while performing noise analysis processing in the form of third octaves spectrums, average SPL, peak SPL and percentiles. We are also working on a real time sound exposure level (SEL) module in an upcoming firmware/software release. This product integrates with our wireless topside buoy, TR-FLOAT, so users can seamlessly monitor underwater noise up to 7 km away from the deployed TR-ORCA, which is ideal for noise mitigation projects.

Yes, the TR-ORCA includes a powerful, but simple and easy to use scheduler. Users can set up their device to enter an extremely low power state and wake up on a specific schedule where it can either record data, process data, or stream it live. The scheduler is an easy way to extend the duration of any deployment.

The base TR-ORCA package is very small and positively buoyant. The easiest way to deploy is over the side of a vessel, or simply anchored to the ocean bottom with a pickup buoy. For deep deployments an acoustic release may be required. Versions of the TR-ORCA with larger battery packs can be easily deployed using our elliptical float collar, or rigidly mounted to a bottom platform, or inline on a mooring. Turbulent Research also provides a real time topside buoy for extra power and wireless data transmission, this is an excellent solution for real time noise or marine mammal monitoring and mitigation.

Raw data is recorded as standard .wav files. Processed and sensor meta data is stored in our proprietary binary formats. Downloads occur using two methods, high speed USB for extremely easy and fast downloads (~40MByes/s), or over Ethernet. Data stored in a binary format can be converted to a standard .csv format using our included converter software. Files can be analyzed in a number of different commercial software packages.

There are two possibilities for integrating other sensors with the TR-ORCA. The user can use a spare input channel to sample analog information from another sensor, or a digital stream can be captured from an external sensor. Care must be taken to not exceed maximum input levels when using hydrophone channels for external analog information. At this time, the TR-ORCA does not support capturing a digital stream from an outside instrument, though this is planned for a future firmware release. Please contact us about any custom sensor integration requirements.

Yes, the TR-ORCA keeps its own time with a real time clock. This clock gets synced to UTC or computer time every time you connect to TRAC. Our real time buoy TR-FLOAT allows for real time wireless transmission of raw acoustic data, and also provides GPS information to TR-ORCA. It is possible to synchronize TR-ORCA time to GPS time. All recorded files are time stamped with the real time clock time. 

Yes. All of the hydrophones are synchronously sampled and the five elements allows for non-ambiguous array designs for localization. The TR-ORCA can even capture data from harbor porpoise clicks in excess of 130 kHz and localize on these common events. The TR-ORCA has also been used in digital beamforming applications with small compact arrays.

TR-ORCA was originally designed for a specific use. That was to localize passive sources over a really wide acoustic bandwidth. Through research and experience we have found that five element arrays give better performance than four element arrays in beamforming and localization applications. The fifth channel can be used in a small compact circular array as a center element, which allows for simple beamforming, and bearing estimation at moderate frequencies. While the extra element in the middle of a tetrahedral array can give excellent non-ambiguous results for time of arrival applications at ultrasonic frequencies, like those used by harbor porpoise. Below is a plot of some cardioid beamforming results with five hydrophones directly connected to our end cap in a small circular array configuration.

Five hydrophone inputs gives a massive advantage over single hydrophone systems. Not only can you use these inputs for localization, but you can also sample at varying depths in complex acoustic environments, or use hydrophones of different sensitivities and characteristics on different channels to maximize dynamic range.

Yes, the TR-ORCA is the perfect candidate for particle velocity estimation using the phase gradient method. Because of the five synchronously sampled inputs, the user can capture coherent data streams using their own arrays; a circular array with a center element is a great candidate for particle velocity estimation.

At this time no, although this is something we are considering for future firmware releases. Please contact us if this is an important feature for you.