SonoBat Bat Detector Software


SonoBat 3 is the most powerful
bat call analysis software in the world.
SonoBat 3 with automated species classification


SonoBat 3 enables a powerful call classification filter system to run on an entire folder of files and output results to a spreadsheet.

Please join us for the upcoming SonoBat workshop!

Modern, intuitive, easy to use
SonoBat software provides a comprehensive tool for analyzing and comparing high-resolution full-spectrum "sonograms" of bat echolocation calls recorded from full spectrum (i.e. time-expansion and direct recording) bat detectors. With its intuitive interface, SonoBat makes it easy to record, process, display, and analyze calls with great sophistication. With SonoBat, you are viewing your bat calls in three dimensions: time, frequency, and amplitude.

Current detector technology enables long-term, uninterrupted recording of full spectrum sound data to enable confident species classification. SonoBat 3 brings automated processing of recorded files and automated species classification- indispensible tools for analyzing long-term and large-scale survey and monitoring projects.

SonoBat is fully compatible with the following bat detector hardware:

Pettersson D240x, D500x, D1000x

Binary Acoustic Technology AR125, AR180, FR125

Wildlife Acoustics SM2BAT, EM3

SonoBat should also be compatible with any other full spectrum bat detector hardware generating a .wav file. The extensive call libraries that form the filter decision engine of SonoBat 3 were recorded using Pettersson D240x detectors.


Myotis septentrionalis successfully classified correctly by SonoBat 3


Comparing calls is easy
SonoBat lets you append reference calls to a call sequence or an individual call and display them on the same sonogram at identical time and frequency scales. No opening of other call files in separate windows and manipulating them to compare is required. SonoBat does that for you automatically with point and click simplicity.


Call sequence compared to a single reference call

SonoBat can process calls into very high-resolution standard view sonograms to display nuances of call morphology, compare unknown calls to reference calls using the same time scale, and enable on-screen analysis of call data.

Unusual Corynorhinus townsendii call compared with reference call

Why use a full-spectrum detector?
Because you will detect more bats. Side-by-side testing has shown that time expansion bat detection in particular is more sensitive than zero-cross detection used by Anabat detectors and retains more accurate representations of both high and low frequency components of bat calls. Read Brock Fenton's abstract from the 30th annual North American Symposium on Bat Research (Miami, FL, September 27-30, 2000), (2000) Bat Research News, 41:116.

Because you can more confidently discriminate species. The sensitivity of time-expansion detection coupled with the high-resolution processing of SonoBat will reveal essential discriminating features often missed with low resolution Anabat processing. Read about one such feature in Joe Szewczak's abstract from the 30th annual North American Symposium on Bat Research (Miami, FL, 27-30, 2000), (2000) Bat Research News, 41:141.


Utilities included in the SonoBat suite

SonoBat Autorecorder
With an auto-triggering detector such as the Pettersson D240x, this utility automatically downloads files to your computer with a location, date, and time stamp. The AutoRecorder lets you automatically record files and have them saved as SonoBat *.wav files, possessing SonoBat file attributes. You can then analyze them using SonoBat or other signal processing software. This greatly facilitates monitoring efforts, particularly when you would like to simultaneously monitor multiple sites, or tend to other tasks.

Autorecorder in action

SonoBat AutoParser
The AutoParser lets you record files from an autotriggering time expansion detector (e.g. Pettersson D240x) using a suitable digital recorder* such as the Samson Zoom H2 and then parse the bat pass events into individual files stamped with the date and time of the pass.

The AutoParser scans through a digital recording to extract sections that have a signal amplitude above a designated threshold and save them as separate files.

Simply set the date and start time of the digitally recorded file, add notes, settings, and a filename start, and then the AutoParser will name the files by appending the date and time of the recordings to a text header. You can then analyze the files using SonoBat or other signal processing software.

* Note: H2 Zooms can now be updated with newer firmware that automatically parses the recordings as the D240x plays them, thereby eliminating the need for the AutoParser when using these newer units.


SonoBat AutoParser extracts bat calls from digital recorders


Batch Attributer, D500x File Attributer and Dated Batch Attributer
The Batch Attributer takes the files you recorded with a generic recorder like an Iriver or Zoom and saves them with SonoBat attributes, custom notes, and filename nomenclature that you specify. The D500x File Attributer does this and more to files recorded with the D500x, including unlocking files, renaming files based on the time stamp in the file metadata, and scrubbing files if desired. The Dated Batch Attributer is used to add time stamps to pre-parsed calls recorded with H2 Zooms that use the new firmware (see Autoparser note)


D500x File Attributer is the first step in post processing any data recorded with the new Pettersson D500x.

SonoBat Batch Scrubber
The Batch Scrubber will scan through a specified directory to recognize files lacking bat calls, for example files triggered by noise and move them into a directory named "Scrubbed Files" in the same directory as the searched files. The search logic seeks signals with a smooth trend in frequency to retain all but the weakest (and probably unusable) bat signals. To avoid missing bat calls, some non-bat signals with a smooth trend in frequency will pass through without getting scrubbed. There are three usuer-selected filter strengths available.

Autotriggering detectors like the Pettersson D240x can produce many noise-triggered files. The Batch Scrubber can save you valuable time by automatically removing these files, particularly from monitoring initiatives producing hundreds and perhaps thousands of files to process.


Scrubber will rapidly scan a folder and recognizes non-bat files.


SonoBat RefCompiler
Use the SonoBat RefCompiler to build your own reference view compilations. You can extract representative chirps from a positively known call sequence and assemble or splice those selected chirps into a new file. Use this known reference file in the future, it can be displayed alongside unknown calls for comparison.

SonoBat Support
Download and view this presentation to learn the details about the basic functions of SonoBat.

Download and view this presentation to learn the details about what SonoBat 3 does and how it does it.

View a presentation on how to use the Batch Attributer.

View this PowerPoint guide for Zoom H2 recording for how to set up and use these units with your D240x.

View a movie clip of SonoBat 3 in action.

Learn about the difference between SonoBat and ANABAT.

Download a spreadsheet output from the SonoBat 3 automatic classification SonoBatch function recorded with a D500x in Trough Creek State Park, PA.


How to purchase SonoBat today

SonoBat Version 3.x
Includes installation CD, printed manual, stock reference calls, plus special stereo-mono audio cable for Pettersson 240x/Zoom/laptop connections. This version includes the automated species classification feature organized by regions. Please select from the following regions Northeastern US, Ontario, US West, US Great Basin, US Montane NE, WA, or OR.
Ships in days.
$1,536.00 USD Full Version, per region
$1,216 USD Upgrade from SonoBat 2.x

Please select version type,
operating system, and regional pack:


Additional discounts apply when purchasing 3 or more software licenses of SonoBat 3.x: 3– 6 licenses, $1248 each; 7 – 12 licenses, $1014 each; 13– 20 licenses, $896 each. Please call 717-241-2228 to obtain these discounts.

Tryout SonoBat right now: download the SonoBat 3 demo
for Windows or for Mac OSX Intel.

SonoBat Version 2.9.5
Includes installation CD, printed manual, stock reference calls, plus special stereo-mono audio cable for Pettersson 240x/Zoom/laptop connections. This version features automated parameterization and other automated features, but does NOT include automated species classification. Ships in days.
$320.00 USD

Select Computer OS Version:

Additional discounts apply when purchasing 3 or more software licenses of SonoBat 2.9.x: 3– 4 licenses, $220 each; 5 – 10 licenses, $180 each; 11 – 25 licenses, $140 each. Please call 717-241-2228 to obtain these discounts.

Tryout SonoBat right now:
download the SonoBat 2.
9.5 demo.


Note: SonoBat is actively developed with frequent updates. Your SonoBat (either version) ships directly from the developer to ensure you always receive the latest version. If you are ordering other equipment simultaneously, SonoBat ships domestically separately from the rest of your BCM order. International orders are held until the entire order is filled and your order ships all at once. More info? Download a PDF brochure on this product...


Getting started? Choose an Acoustic Survey Package

The Pettersson D500x is one of the most reliable, user friendly bat detector available. The D500x is designed for sup to several months of automated recording. It's microphones are perfectly compatible with SonoBat 3's automated analysis straight from the detector. This package is a complete setup that meets the 2012 USFWS Indiana bat sampling protocol.*

Total Acoustic Survey Package
  • SonoBat 3.x (your choice of one regional pack below)
  • (1) Pettersson D500x FS:DR Bat Detector
  • (1) D500x external microphone
  • (1) 25' external microphone extension cable
  • external microphone mount (1) 45° and (1) 90° slips on our 1H mist net poles or simply taped to your preferred mounting stand
  • (1) weather resistant storage box (holds all of the above in storage and deployment)
  • (1) BatCalls DVD (to familarize yourself with real recordings)

Ships in days in two shipments. $5,000+ retail value.
$3695.00 USD

Please select SonoBat version type,
operating system, and regional pack





Confused about acoustic monitoring for bats?

AM is more complicated than it appears. How do you know if what you are recording is any good, if you don't know what it's supposed to sound like in the first place? Please see our acoustic help section particularly for placement and weatherproofing suggestions.

A note about placement and weatherproofing in the draft 2012 Indiana bat survey protocol

  • NEVER place bat detectors directly on the ground. Insect noise, warm air currents, and the extra distance from where bats fly will all contribute to degrading the quality of recordings.
  • NEVER place a full spectrum microphone inside of reflector tube as recording quality will be seriously degraded. The Pettersson D500x microphone is weather resistant and will survive occassional showers if fully dried before storage. For long term deployments, this microphone should be elevated above the ground and orientated horizontally into the airspace you expect bats to occupy.

SonoBat Features

Runs identically on Windows and Macintosh OSX platforms (Intel processors only, PPC no longer supported), and call files may be swapped between the platforms.

Operates entirely by a graphical user interface, although there are key shortcuts for the most-used operations.

Reference calls can be appended to a sequence view and are automatically adjusted to match the time and frequency scale of the view. view screenshots

Any call may be selected for very high resolution standard view display and have a reference call displayed beside it with matching time and frequency scales. view a screenshot

Any call displayed in standard view may be stored with an accompanying text note as a reference call, including the time position of the call within the parent file. view a screenshot

Compiled reference views allow a range of call varieties from a single species (or more) to be displayed in a single view. With a library of compiled reference views, you can quickly compare an unknown call against the calls of a variety of candidate species. view a screenshot

Extensive analysis functions using screen-positioned cursors: low/high frequency, bandwidth, duration, call interval spacing, heel, slopes, characteristic frequencies, harmonics. view a screenshot

File navigation is shortened by saving call directories and the reference call library along with other user settings in a preference file, and an intelligent file dialog. view a screenshot

Time and frequency scales are programmed to match x10 time expanded audio data. Customized versions are available for other time expansion factors.

Calls are processed from standard wav files. Acceptable wav formats are 22.05 kHz/8 bit, 22.05 kHz/16 bit, 44.1 kHz/8 bit, 44.1 kHz/16 bit. The software automatically recognizes and displays which format.

Calls may be recorded in any of these wav formats with the Recorder Accessory, which provides real time amplitude feedback during recording. view a screenshot

The Recorder Accessory allows the selection of desired segment before saving to file. This is especially useful for selecting a continuous sequence from a looping audio output. view a screenshot

Call files in 44.1 kHz/8 bit and 44.1 kHz/16 bit format are processed to display frequency information up to the maximum frequency resolution of the detector that acquired the call sequence, e.g. 175 kHz for a Pettersson D980 which samples at 350 kHz. Call files in 22.05 kHz/8 bit and 22.05 kHz/16 bit format are processed to display frequency information up to 110.25 kHz, the upper limit of frequency information at this recording rate. (Keep in mind the difference between the detector's sampling rate of the actual sound, and the digital recording rate of the x10 time expanded audio data.)

Very large files open in a segment-select mode. The length of the segment is user-definable to match the performance characteristics of the host computer. In files requiring segment selection, the selected segment remains in the selected location for reprocessing if selected parameters are changed, e.g. a filter setting.


A selection of filters are available: 5 kHz and 20 kHz cut off filters to eliminate low frequency noise, and a special harmonic emphasis filter. view comparative screenshots

Call sequences can be opened in a real time view mode, or a compressed view mode in which the "dead air" space between calls is compressed; the degree of compression discrimination is user-controlled. view screenshots

All calls and call sequences can be played. In compressed view mode, an intelligent time position cursor waits during the "dead air" pauses.

Reference calls of a different wav format than the currently displayed file are automatically converted to match the display file.

With a reference call appended, calls may be compared aurally as well as visually.

In compressed view mode, the call interval times are automatically calculated and displayed.

A "hold frequency" zoom mode permits zoom selection of time segments without affecting the frequency scale.

Multiple zoom recovery with a single click.

Pop-up contextual help messages may be enabled. view a screenshot

Audible feedback of most button clicks. However, all sound play may be turned off.

Real-time adjustment of display amplitude intensity and threshold, i.e. the sonogram display changes immediately as the controls are adjusted. view comparative screenshots

Real-time sonogram palette changes from black background to white background, and color to grayscale (useful for printing and publishing); also, exclusive contour display of intensity levels in grayscale. view a composite of screenshots

Print window feature of the current sonogram display.

Automatic adjustment of amplitude range. This enables comparison of faintly recorded calls with those of full level recorded calls.

Adjustable ruler can be displayed for comparing frequency of calls across the sonogram display. view the active ruler on this screenshot

In compressed mode, standard view selection is automatically referenced from whatever piece of a call that is zoom-selected. In real time display, the standard view is centered on the zoom-selected view.

A call displayed in standard view displays itŐs time position within its parent sequence.

Seven standard view lengths are available: 10, 15, 20, 30, 40, 50, and 100 milliseconds.

Analysis data may be written to a spreadsheet.

Automatic calculation of real positions of aliased harmonic components. This allows the use of frequency information as high as 350 kHz


SonoBat 3 Auto-Classification Notes and Warnings

The species decisions generated by SonoBat 3 should be considered as suggested classifications. Any final conclusions regarding species presence should be confirmed by a qualified biologist with knowledge of bat echolocation call characteristics and the limitations imposed by species having similar call characteristics. Although some species have distinctive call types that facilitate confident identification, other species exhibit similar call characteristics that reduce the reliability of using bat echolocation calls as a sole indicator of presence. In some instances irrefutable species confirmation may require a "bat in hand." No acoustic detection technology available today can reliably distinguish bat species with absolute confidence or even reliably detect all species and it would be a misuse of this technology to rely solely upon acoustics in absence of a presence-absence/non detection survey employing physical capture methods.

The SonoBat 3automated species classification algorithms are based upon several thousand species-known recordings (sample size varies from species to species) from specific sites within each geographic region covered. While derived from a robust data set acquired from a variety of environments and conditions, the data set nevertheless encompasses a finite set of vocalizations from each species covered. Bats exhibit considerable plasticity in their vocalizations, and considerable overlap in call parameters among species; this coupled with complications from noise and weak signals (as from bats at a greater distance from the detector) can potentially result in a recording from one species with parameters that match the expected parameter space of another species, resulting in a misclassification. For example, the call shapes of shorter Eptesicus fuscus and Lasionycteris noctivagans may include calls that overlap in data space with sufficient ambiguity to result in misclassification.

Because bats vary the amplitude through their calls, the farther a bat flies from the detector, the more the call becomes truncated to just its strongest portions. In some cases these fragments of fully formed calls can mimic other species, e.g., the body fragment of a Myotis lucifugus may render as a simple curved call that mimics a Lasiurus borealis. SonoBat performs a number of signal quality checks to reject poorly formed calls, overloaded calls, or those with distorted signals or too much noise, but because of the variability in bat calls (e.g., intra-specific variations, social calls, feeding buzzes, inspection calls, etc.). Classification remains a probabilistic process, so generally if a classification result seems unexpected, it is the end user's ultimate responsibility to check it or reject it. The quality of call recordings strongly affects the performance of the SonoBat autoclassifier. Recording from the ground, near flat surfaces, or through tubes will render distorted signals. Signal distortion inhibits call trending and the recognition of call parameters essential to perform accurate classifications. In summary: Garbage in, garbage out.

Even among the known species of the library reference data, the rate of correct classification varies by species, situation, and settings. In general, the longer duration calls that many species produce in open-air flight, i.e., away from clutter, provide greater species-discrimination confidence. Also, SonoBat allows the user to control call discrimination settings and in general, more discriminating settings increase the rate of correct species classification (up to a point) but decrease the percentage of files that SonoBat accepts and reports as confidently classified.

Above all, for some species, confident species classification can only be achieved on a subset of call types within a bat's repertoire that falls outside of data-space shared with another species. Not all recordings can, or should, be identified to species with any degree of confidence.

Users should understand these applications and limitations of the autoclassifier and expect their results to vary depending upon recording quality and other factors as described above.


Benefits of full-spectrum data and processing

Although call parameters from the time-amplitude domain do increase species classification performance, the primary benefit of full-spectrum analysis comes from increasing the robustness, accuracy, and confidence of certain bat call frequency metrics familiar to users of zero-crossing methodology, yet these metrics are rendered more accurately in full-spectrum analyses due to the less-sensitive nature inherent in frequency-divided recordings. In summary: full-spectrum provides higher quality results.

The full-spectrum approach enables and supports automated processing and classification of bat echolocation sequences. Moreover, the enhanced information content of full-spectrum data compensates for and decreases the need for human attention and artistry in the interpretation of less information-rich data. Some examples of conditions that can confound accurate call analysis using a frequency-divided approach are illustrated below.For a more complete overview of the benefits of full-spectrum analysis of bat echolocation calls, and the differences in data interpretation between full-spectrum and zero-crossing, view this presentation.


Full-spectrum recording viewed with SonoBat
Frequency-divided rendering of the same call
Full-spectrum (with SonoBat call trending) and divide by 8 zero-crossing interpretations of the same Myotis californicus call signal in the presence of noise.


For a more complete overview of the benefits of full-spectrum analysis of bat echolocation calls, and the differences in data interpretation between full-spectrum and zero-crossing, view this presentation.
Full-spectrum processing rendered a complete time-frequency trend and confident determination of call parameter data from this Indiana bat call despite insect noise. Because zero-crossing analysis can only detect the strongest frequency component at any time interval, zero-crossing analysis of the same signal could not render a usable time-frequency trend because of the stronger low frequency content of the insect signal.
The overpowering concurrent signal amplitude that prevents full zero-crossing recognition of bat time-frequency trends more seriously affects bats that vocalize more quietly such as this Corynorhinus spp., shown beside the same signal rendered by zero-crossing. The multiple frequency content available in full-spectrum data enables tracking the time-frequency trends of calls to completion even when the call amplitude falls below the maximum amplitude of other concurrent signals.
An example of a full-spectrum enabled time-frequency trend rendered through clutter echoes. In this case, the ending downward trend in frequency readily discriminates this Tadarida brasiliensis from a Lasiurus cinereus, whose calls tend to turn upward at the end. The zero-crossing analysis followed the stronger echo signals at the end of the call, suggesting an upward trend, and potentially confounding an accurate species determination.
Echoes from clutter will often obscure ending details of calls. In this example, the time-frequency trend processed from full-spectrum data revealed the downward ending frequency trend that assists in recognition of this as a Myotis spp. call.

The time-frequency trend as rendered from zero-crossing the same signal rises up at the end from the effects of noise and clutter echoes. The resulting trend has more features in common with an Eptesicus fuscus call than a Myotis spp. call.

Some bats like this Leptonycteris shift power among their harmonics, and zero-crossing trending follows the strongest power of these shifts generating interrupted time-frequency trends. Experienced zero-crossing users can recognize these shifts and make assumptions about call continuity, but they complicate automated analysis by zero-crossing. Full-spectrum processing readily generates an uninterrupted trend with such data.
In this Corynorhinus townsendii call, the power shifts to the second harmonic late in the call, and the trend points from zero-crossing processing jump up to the higher powered signal. With access to multiple frequency content, full-spectrum processing can generate uninterrupted time-frequency trends from which to determine call parameters with greater confidence and detail for accurate species identification.
With some species, the call fragments acquired from out of range bats, or noise-burdened signals processed by zero-crossing, can leave fragments that mimic the fully-formed calls of other species. In this example, only the higher powered core of this Myotis thysanodes call rendered trend points from zero-crossing analysis and these left a signal that mimics a Corynorhinus townsendii call. The higher quality time-frequency call trends supported by full-spectrum data minimize this source of error.

The amplitude and multiple frequency content of full-spectrum data enables assessment of signal quality. For example, one such measure, the signal to noise ratio (SNR), measures the relative strength of a signal of interest (the call) to the strength of the background signal level.

Calls with low SNRs may generate unreliable parameters and are best excluded from contributing to sequence-level species classifications. This measure would reject the call in the above example. Such metrics provide essential quality control for automated call and sequence classification.


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