Review: Mammut Barryvox S2 Avalanche Beacon

• Size: 4.5” x 0.8” x 2.7”
• Weight: 180g
• Stated Range: 70m
• Multiple Burial Marking: Flag button, Scroll Buttons
• Additional Features: Customizable Pro Mode, Analog Sounds, Group Check, Pro Check, Interference Warning, Auto-diagnostics, Bluetooth App Connection, Auto-Revert, Vital Data transmission, Signal Selection (in pro mode), Bluetooth Channel, Rescue-Send Mode, Audio guidance (only available in certain locations)

Recall Notice:

Mammut issued a recall on the first batch of devices sold in November 2024 due to a potential defect in the power switch mechanism. Devices sold on Mammut.com from 11/19/2024 onwards have been checked and are not affected by the November 2024 recall. Check directly with Mammut if you own a new Barryvox S2 and are unsure whether your beacon has been checked.

Features and Interface:

The most impressive part of Mammut’s Barryvox S2 interface is how customizable it is. There’s a standard search mode, and a pro mode that unlocks a whole suite of extra features including analog search tones, and the ability to scroll through signals if you are searching for multiple buried victims. The beacon is switched on and off and from send to search modes using a slider switch on the top, much like the older one. 

Out of the box, the default search interface features really intuitive visual guidance on the large screen, with large cartoonish icons indicating what you should be doing during each phase of a rescue (signal acquisition, coarse search, fine search, and probing). Once in fine search mode, the beacon automatically switches to Mammut’s Intelligent Fine Search, which guides you through doing a fine grid search. 

This feature is actually really cool, as it help you to keep your beacon oriented properly, and will often eliminate the need to perform a full grid search by quickly identifying the point where the strongest signal came from without having to do a full cross–saving valuable time during a real rescue. For more on how this feature actually works, check out page 28 in the Barryvox S2 Extended Reference Manual.

There’s a large button on the front to flag a signal, and the beacon will automatically switch to the next strongest signal.

In Pro Mode, it’s possible to customize the interface, including turning off the Intelligent Fine Search mode and turning on signal scrolling. Beyond the interface, perhaps the most powerful function of Pro Mode is turning on analog search tone, which allows a rescuer to identify signal overlap and other potential complications in a complex multi-burial situation. Really, no recreational user should ever need to use these functions, so I won’t dive deep into them, but if you’re a pro and looking to learn more, check out pages 33-43 in that Extended Reference Manual.

All Barryvox beacons (including the older models) feature the ability to transmit what Mammut calls Vital Data (essentially whether a buried victim has a heartbeat that’s sensed by the built-in accelerometer) to other Barryvox beacons. This only works Barryvox to Barryvox via a secondary bluetooth channel that’s not the standard 457 kHz channel. It could be a useful additional triage data function in the case of a mass burial.

The beacon now uses two AAA batteries, and is compatible with both alkaline and lithium batteries. Depending on your preference, the beacon can be carried in an included harness, or clipped to a leash inside a beacon pocket.

Here’s how we tested beacons:

This year, we tested all our beacons identically, first in a standard range test, then in a search strip width (receiving range) test, and then in a controlled setup mirroring the PRO 1 Multiple Burial Rescue Exam (a standard test that all backcountry professionals are tested to). As a baseline for the multiple-burial test, we buried two identical Mammut Barryvox S beacons in a large flat area, under 50cm of snow.

We tested the receiving range of all beacons to see how close the rescuer would need to get before the searching beacon picked up a buried signal. We put a single Barryvox S at the far end of the field, and then walked towards it from 100 meters away using each test beacon, marking the spot where it picked up a signal, and measuring that distance. This was repeated multiple times per searching beacon with the transmitting beacon in multiple places (to account for some variation caused by the environment), and the distances were averaged.

After checking ranges, we performed the PRO 1 multiple burial test (minus the shoveling) to learn more about the efficacy of each test beacon when searching. This was performed multiple times per beacon, with various testers including myself, two AMGA ski guides, and several testers with varying levels of recreational experience. We timed each test and took notes on the specific performance of each beacon.

The Mammut Barryvox S2 vs. The Search Strip Width Test

During our search strip width test, the Barryvox S2 picked up a signal at an average of 70 meters (right in line with the advertised 70m search range). With the knowledge that Barryvox to Barryvox coupling often works better, we repeated the test by searching for various other beacons, and the range shortened slightly, but still remained in approximately the 65-meter range.

The Mammut Barryvox S2 vs. The Multiple Burial Test

Given that the Barryvox S2 is largely a different beacon with its two interfaces (standard and pro mode), we ran the multiple burial test in each mode to learn more about each.

When performing the multiple beacon rescue scenario in standard mode, a few things stood out. Unlike the older Barryvox S, the S2 has much faster signal acquisition and processing, meaning that once a signal is acquired, it will lead the searcher into the general area of the buried victim very quickly. The Intelligent Fine Search mode works even better than it did before, but some testers do note that it can be hard to remember to keep your beacon oriented correctly (do not pivot it around the vertical axis!) during this phase of the search. Barring that, testers found it very intuitive and quick to use, noting that the marking function was the easiest and fastest to use out of the group test. Overall, after mastering the fine search mode, testers were able to perform the multi-burial drill the quickest using the Barryvox S2 compared to our other test beacons.

In pro mode, things got interesting. Testers who had never used this mode and did not know how it worked actually found it very difficult to use compared to the intuitive standard mode. In pro mode, the beacon gives you WAY more information and that can be quite overwhelming in a high-stress rescue scenario–however, if you know what to do with that information it can actually make complicated rescues much faster.

I would not call myself an expert by any means, but I have been lucky enough to receive several hours of instruction on how to use these features from mountain guide and Mammut ambassador Doug Workman and some Mammut athletes, so I would consider myself to have a workable understanding on how to use it. That being said, it’s not a particularly intuitive feature set to use for non-pros, and I wouldn’t recommend switching your beacon to pro mode unless you have a good reason to. I personally still don’t use all the pro functions when I go into the field.

We have not had a chance to use the voice guidance system so far.

How Does the Mammut Barryvox S2 Compare?

Compared to the other beacons we tested this year, the Barryvox S2 stands out for both its robust feature set in pro mode and the innovative Intelligent Fine Search mode in the standard configuration. Also, if you care about this kind of thing, the Barryvox S2 is the thinnest and lightest beacon we tested–but more importantly, we saw it repeatedly perform slightly faster in our real-world tests.

Who is the Mammut Barryvox S2 best for?

Clearly, the Barryvox S2 is a beacon designed for professional use, and that’s undoubtedly who it’s best for. However, it would also be an excellent choice for frequent recreational backcountry users who are looking to get a little more out of their beacon, or might have ambitions to join a SAR team, guide service, or ski patrol at their local hill. The range is great, the features can be effectively customized, and we think that ol’ Barry would be proud of what’s been named after him.