Put simply it's an electronic device that is normally mounted on or in the helmet of a skydiver which will beep as the skydiver in freefall (or at a high enough descent speed to trigger the audible) passes through a pre-determined altitude.
The device measures air pressure. It knows when you switch it on that it (or at least it should be) on the ground, and will calibrate itself to ground level - it will normally continue to self-calibrate to the ground level until powered down.
As you ascend in the aircraft, the device registers that you are now on the climb to altitude - and will sometimes (device dependant) show you the altitude you are at. As you increase in altitude during the aircrafts ascent the air pressure drops, as you descend in freefall - the air pressure once again increases relative to actual altitude.
The device may have pre-set unalterable heights or it may allow the user to change one or more of the heights at which it is triggered. As a skydiver passes one of these heights the device will activate - which normally means it will emit a shrill BEEP into your ear. The device can register you as in freefall, or at a high enough descent speed to warrant activating because your speed can be calculated by the device as pressure change over time. The device may have a number of altitude points at which it will sound and may have more than one type of beep.
Yes, Skydiving electronics are quite expensive, but just because you're using it as an audible, doesn't mean that is all it is limited to. Also, the devices are incredibly accurate and some are able to measure within 10ft, and log thousands of points of data for download and analysis at a later time.
That actually depends on the make and model. However, there are some that just beep at pre-set heights, some flash and beep using extra wires connected to lights, some keep your information in the form of a full digital log book, some have visual displays and some have modes for canopy flight too.
You get what you pay for. A cheap device is probably just going to beep, whilst a mid-range one is likely to at least hold your log book data on top of acting as an audible and the really expensive one will do everything but fly your canopy for you.
There are several manufacturers of audible devices, so we've taken a look at the most common ones - but the list is by no means a comprehensive one. We've also noted down how much they cost, and what other features they have, so you should be able to figure out which ones you would like to look at up close.
The SOLO II superceeds the SOLO mk 1 and is by far the most simple and cheap option to go for when buying a new L&B Audible product. It has three adjustable altitude triggers which can be visually identified by the LED, making it easy to know if it is set at the correct height for your next dive.
You can choose between 1,2 and 3 alarms.
Alarms 1 and 2 are warning beeps, with alarm 3 as a high pitch siren.
Adjustable heights are altered in increments or decrements of 500ft.
This is an audible only, and does feature any form of integrated digital log book.
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Quattro is quite similar to the SOLO II device, however it is more often used by big way and wing suit jumpers in addition to higher altitude jumps. The highest freefall alarm can be set at 19,990ft.
The Quattro has a significantly improved accuracy over the SOLO II, which is what makes it popular with wing suit flyers, big-way and competition jumpers.
In addition to the accuracy and height, the device features different pulsating tones - which again make it popular for big way groups that break off in staggered groups.
For those who are also interested in canopy flying - the device has three low speed descent alarms which could for anything from training on a new canopy, a reminder for the novice to check their down wind leg, or even CRW jumpers to break off for their formations.
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The Optima II superceeds the Optima device.
This audible has 3 warning altitudes which can all be individually set. The first two are 'pulsating tones' with the third and final alarm being the high pitch siren. Like other L&B audible devices, you can set them to use 1,2 or all 3 alarms.
There are also volume control options for both the free fall and canopy modes. The SWOOP mode has 4 memory banks for sutom warning settings and there is a 7 step pitch warning which helps you know exactly when you'll hit that 'sweet spot' for the perfect entry point of a high performance turn.
Like the Quattro it has altitude selection in steps as small as 10ft, and the Optimum II can be bought as a visual altimeter (uses an additional piece of kit) which would plug into a port seen on the side (note that the port is sealed on this 'non flashing' edition)
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The NeoXs manufactured by ParaSport is easily identified by the joy stick style remote control and the use of metal rather than plastic as an outer casing.
Featuring 3 alarms for free fall and another 3 alarms for under canopy, the device even features a countdown timer, so, like other devices, you'll know as it gets close to the trigger point.
NeoXs is also configurable whilst climbing to altitude - so when someone decides that they want to break off higher up, you can easily adjut your break off altitude warning height to match.
Preset user profiles make it a great tool for instructors swapping between different jump types such as going from Tandem to Experienced coaching.
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ATLAS is the latest model of audible altimeter from Alti-2, and whilst it is obviously a visual altimeter, it boasts an impressive 8 alarm groups.
Alarms are also customizable using the Paralog or Neptune Maintenance Utility (NMU) which makes it great for skydivers that swap between disciplines.
Like the NeoXs it is also made using a more durable machined aluminium construction rather than plastic construction and has a fully integrated digital log book too.
The N3, manufactured by Alti-2 is first and foremost a visual altimeter and integrated log book, however as it has the ability to act as an audible device - has therefore been included.
The device has 8 alarm groups which include both freefall and canopy alarms. Using the maintenance utility you can create up to 32 unique alarm names, which makes it great for different setups. Alarm tones can also be customised and alarms for the canopy section include approach alarms. Instead of it just going off at the designated trigger point, it will give you a notice period that you are approaching your set height marker.
Alarm volumes also have an extra loud option - if you're wearing it on your wrist as an altimeter.
The Skytronic GFX is a one device does all piece of equipment. A visual altimeter and fully incorporated digital log book, it also boasts a number of alarms.
There are 3 freefall and 3 canopy alarms with the option to have a countdown timer make this device similar to a number of competitors. There are 9 user presets, which is generally more than most will need, but each can be given it's own unique name instead of preset 1, 2, 3 and so on.
The "Time Out" was litterally the very first commercially available audible device, but has long since ceased trading. The device led the way for the modern audibles we have today. They are still occasionally seen around the DZ and for sale online.
The device only had a single audible alarm height which could be set by the user, and was incremented or decremented in steps of 500ft. The remaining alarms were hard coded into the device - which always operated in ft.
Compared to current audible devices, they are somewhat thicker and more bulky than the modern devices - however given that they were manufactured nearly two decades ago - they have withstood the test of time incredibly well!
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The ProTrack - One of the most popular audible devices of all time as it was one of the first devices in the world commercially available that could track and log the jumps at the same time as acting as an audible device.
Many of these devices are still being sold as second hand units, however they are officially discontinued products. They featured three user defined alarms with pulsating tones on the first two and a siren warning alarm for the third and lowest altitude.
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The device was superseded by the SOLO and then the SOLO II. It was a popular device and often the first choice for an additional or backup audible device.
Essentially a slightly stripped down version of the Pro Track, this device has many of the same features as the modern day SOLO II, however is reported that the accuracy of the newer SOLO II is significantly increased, making it more reliable and giving better readings.
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The DYTTER was the model originally created by L&B before being succeeded by the Pro-Dytter. Height adjustment for the one available alarm was operated via the brass disc which was operated by turning with finger or thumb. Height incremented or decremented in 500ft units.
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