Headphones also need to be compatible with other equipment such as helmets, work in difficult conditions (heat, cold, humidity and dust) and integrate with various communication systems of the platform.
Old and new
Such a large number of requirements makes it problematic to manufacture tactical headsets that would fully meet the needs of soldiers and at the same time would not be a burdensome piece of equipment. The market for such equipment can be divided between traditional headphone options and newer in-ear (in-ear) devices.
All existing telephone headphones consist of three main components: two telephones with a cup and an ear cushion, connected by a bridge running around the head, which allows you to hear transmitted and delay unwanted sounds from the outside; a mic with a filter to delay too loud noise: and a cable that connects the headset to a radio or other audio device.
In-ear devices use a small earmold that fits into your ear like commercial headphones. However, such a headset also includes a microphone connected by a cable to the radio station on the chest.
Matthew Hemenez of Silynx, a headset designer and manufacturer, said the market is still dominated by headsets. Although these devices still continue to be technically improved, for example, due to advanced anti-noise filters, it is difficult to make the incoming sound much cleaner than it already is.
In his view, "major changes" are occurring at the application level, with soldiers seeing the advantages of in-the-ear devices over earbuds. He also believes that headsets "should be considered unacceptable devices today."
His argument is that the high-cut ballistic helmets on offer today to soldiers are specifically "sharpened" for headset use, as space needs to be provided for telephones. Hemenez noted that the military, along with industry, have decided to remove 25% of the protection that a standard ballistic helmet provides so that headsets can be used, "this is hardly a compromise solution." The argument put forward by him. is that the headsets must be designed for the main platform, that is, the helmet, and that changes to the helmet design to match the headset are "partial optimization".
Agree to disagree?
Manufacturers of existing headsets strongly disagree with such arguments. According to Eric Fallon of 3M Peltor, in-ear solutions can only be worn for short periods of time, after which they become uncomfortable and, "if you pull it out, it is already difficult to insert it back in, unlike headphones."
He said that the experience with earpieces is much richer and that the US Navy Special Forces and the Delta Squad "generally love them." While he acknowledged that some “no experience” commanders believe that ITS is a promising route, he sees the only possible use in situations where a lot of stealth is needed and soldiers need to be discreet.
Chris Moore of Revision Military, which launched the new Sensys ComCentr2 in-ear device in 2017, said that in-ear devices are a relatively new piece of gear. The US Marine Corps (ILC) only accepted these macrodeep liner devices in 2009; purchased more than 40 thousand units have not been deployed in the divisions.
According to Hemenez, advances in the field of in-the-ear products are making them more reliable. He said that Silynx does not use bone conduction technology for its microphones. This approach has been used for some time with in-the-ear headsets, but it requires precise placement of the earmold in the specific part of the ear, where the cartilaginous ridge is present, so that vocal vibrations can be transmitted.
He noticed that they can become a problem for the soldiers, since in the event of displacement or removal of the liner from this zone, communication is terminated. Silynx uses an in-ear microphone as an alternative to bone conduction. This means that the headset can be moved without disrupting the connection, while this solution allows you to hear the whisper much more clearly, which is not the case with bone conduction devices, which have problems with this.
Hemenez's criticisms of headsets are as follows: they add 0.5 kg to the weight of the helmet; in hot weather with closed ears it is very uncomfortable; and they are attached to the helmet and, if removed, the soldier is left without communication. He added that if a soldier is wearing eye protection or goggles, then the temples behind the ears could compromise the seal of the earmold and quickly degrade noise protection.
Consequently, the challenge for companies like Silynx is to provide a compelling case for using in-the-ear headsets, but so far the military's response to this has been mixed. Hemenez believes this is due to the preferences of different generations. Older soldiers who have traditionally used headsets tend to prefer these devices and are therefore unlikely to choose a new piece of equipment they find uncomfortable.
He referred to a 2013 US Army program that procured a small number of in-the-ear devices for testing with the prospect of increasing procurement for all infantry units. However, Hemenez noted that, in fact, the program was rather "experimental" and after three months it was abandoned.
He compared this reaction to that of law enforcement agencies, which have no problems with ITE systems, since the police and others do not have similar experience with headsets and therefore do not find ITE counterparts uncomfortable. “It's about perception. Helmets and headsets are also uncomfortable, but that's a different type of discomfort."
Moore agreed that perception is important and that "progressive people do a better job with ITS, and people who hate change don't even want to hear about it." In his opinion, due to differences of opinion, the military is trying to try both options so that the personnel can choose."
The case got under way with the release of two requests for information on hearing aids. The first in the Communications Accessory Suite-Land was released by the Army in June 2017, and the second in Hearing Enhancement Devices was released by the USMC in September 2018.
In order to best meet the needs of these requests, headphone and in-ear options are provided. We can say that the worldview is slowly beginning to change, and more and more military personnel are recognizing the possibilities offered by in-the-ear devices. However, whether these products will be purchased in large quantities for the army and marines under the official program is not yet entirely clear.
Be the first
While regular armies are rather reluctant to adopt in-the-ear solutions, special operations forces have been using these devices for quite some time. Although the 3M Peltor Comtac III family of headsets is undoubtedly one of the most popular solutions and is used by special forces in many countries, in-ear options have recently gained more and more popularity.
Hemenez said the Australian, British and American MTRs are the leaders here and that the British have been using Silynx products for over a decade. "These special forces completely changed their worldview, which cannot be said about other countries."
Fallon noted that headsets can be used in almost any environment, in all environments, from air and water to desert and dust; they are reliable enough for most operations. This attracts special forces, since such devices can be used, for example: for exchanging messages with the aircraft crew, during parachute jumps, when swimming in water (depth up to 20 meters), on beaches and other sandy terrain.
He added that headphone options include attaching the phones to a rail on a cropped helmet so as not to throw the jumper around the head. This allows them to be shifted if necessary to ventilate the parotid space.
However, as with Silynx's in-the-ear products, 3M also had problems with its testing methods for its in-the-ear products and therefore abandoned them. Fallon noted that it all boiled down to the helmet problem; some soldiers wore helmets of the wrong size when using the headset, explaining this as discomfort.
“The US military has come a long way to understand how important a helmet is to a soldier, especially if you add gadgets to that helmet,” Fallon said. "Regular units are not going to give up high-crowned helmets anytime soon, as the emphasis is on bulletproof protection."
Defense issue
However, due to the fact that conventional armed forces are becoming more technically advanced, the priority of communications is also increasing.
Fallon also cited hearing protection as a key concern, adding that the Department of Veterans Affairs has spent $ 1.5 billion on hearing problems for former military personnel. Hearing protection in headsets must cope with the transition from very quiet to extremely loud scenarios, as well as the sudden events faced by soldiers in combat.
For example, a patrol squad in Afghanistan may spend several days in a very quiet environment in which case there is no need for hearing protection. However, during a clash it quickly becomes noisy, especially when using such weapons as the AT4 hand grenade launcher, the volume of which reaches 180 dB, "while it can negatively affect the hearing organs, sometimes until the end of life." Fallon added that one needs to understand "audio needs as they are complex and must include periods of silence."
However, different types of noise have different effects and the noise of an explosion does not have the most negative effect on hearing. The sustained long-term noise generated by machinery, aircraft, engines and generators has a much greater negative impact due to its persistence and duration.
As Fallon explained, during the shooting, a peak pressure is created that lasts less than a second. Constant noise can damage the hearing organs even at a volume of more than 85 dB; for example, the noise from the HMMWV armored car can be at the level of 100 dB, and the noise from the CH-47 Chinook helicopter at the level of 125 dB. This is more harmful than an explosion with a loudness of 140 dB, a shot from an M4 rifle with a loudness of 164 dB, or even a shot from an AT4 grenade launcher.
Tactical headsets provide hearing protection in two ways. The first is electrical, where the microphones in the headset receive and amplify the noise for the user. This limits any sound louder than 82 dB. The second type is passive protection using ear cushions for the headset and an in-ear for an in-ear headset. Fallon noted that in-the-ear devices may provide better passive protection with higher noise absorption, but in-ear devices still fit the bill.
Moore said the military is looking to move to in-ear headsets because of better single-level attenuation (one set of earmolds).
European Hearing Protection Act EAR352 defines the characteristics of earmolds against continuous noise at low, medium and high frequencies. "Eartips perform better than earbuds in tests, but big problems arise with prolonged use." After four hours of wearing, the ears start to ache, while the earbuds can be worn for a long time.
Time for technology
Looking ahead, though, Moore said there is still room for headset development. He noticed that devices like 3M Peltor's Comtac and the like are analog and while they are "doing their job" there is time to create new advanced devices.
“Over the past 10 years, the in-ear market has brought a lot of technology into the headset space,” he said. This is, of course, digital electronics, which is essential in the production of in-the-ear systems. At the same time, Moore noted that it has never been introduced into the market for headphone systems and that this is exactly what Revision sees as the disadvantage of its ComCentr2 headset.
In terms of hearing protection, Revision has incorporated rapid noise cancellation into its headset when a backwash of audible noise is generated for active partial damping. “We were able to integrate this system into the headset, which gives a huge advantage in the low frequency spectrum,” said Moore. "We've got some results in the lab and can offer a halving of noise in decibels for a low frequency passive headset, which is a very good indicator, since a decibel is a logarithmic value."
Revision also uses a digital signal processor (DSP) in the headset that uses algorithms to suppress noise. This allows you to operate in a wider range of noise environments than if the signal was transmitted directly to the radio station over a standard cable.
There are also advantages in terms of increasing the level of ownership of the environment. "What digital electronics will enable us to do is to significantly reduce the size of the microcircuits and significantly improve the fidelity with more microphones."
Instead of just two forward-firing microphones that record the noise and play it back to the speakers, there are two more rear-firing microphones. By using digital processing and appropriate filters, this allows the user to distinguish between front and rear noise.
Moore said the front-to-back error rate of in-the-ear and headphone devices - especially the latter as they are farther from the ear - can be up to 40% as sounds coming from the front and back mix. "You think that something is in front of you, but it is behind you."
“You can in no way have this front-rear error on the battlefield, as it is very confusing and confusing for the user. That's why we have implemented rear microphones to bring this front-rear information to the user. This is why, in his opinion, it is necessary to achieve proper 3D audio situational awareness, although most competitors will have two front mics, and some just one.
Expanding three-dimensional audio capabilities is to create spatial separation; this is what Revision is positioning as an advantage that sets its products apart from those of other manufacturers. This feature allows the user to listen to several conversations at the same time and then switch to the more important one - in the same way, the ears can selectively block some conversations in the vicinity and better understand others.
“Future commanders will have up to four radio networks connected at the same time. The JTACS system has four networks operating simultaneously, with different names, different equipment and people, but current systems only allow two networks in one ear and two networks in the other at best. Moore explained. - In the worst case, you need to have a different pair of headsets for each network; to receive and transmit, you need to switch between them."
Revision proposes to take these streams of information and process them with a surround sound algorithm known as the Head Related Transform Function, which splits them into two channels (left and right ear), but then tricks the user into thinking that the sound is coming from the space around him. … The sound of each of the four nets seems to come from four different directions, 90 ° to the right, 90 ° to the left, 45 ° to the left in front, and 45 ° to the right in front.
“The consequence is two main effects,” Moore explained. "Firstly, your brain can instantly understand where the conversation and the sound of the radio network are coming from, and secondly, the sound is transmitted to both ears, which makes it louder and more intelligible."
Bindings down
Another technological advantage is the elimination of wires in headsets, since in this case the user can move his head more freely. Cables are the main source of complaints for soldiers regardless of the type of tactical device.
The solution is wireless, eliminating cables, but Hemenez noted that this could create a new problem - separate charging of the headset. In the field, this can become a problem when there is a shortage of power supplies.
Moore noted that wireless dongle-type means are available (any device whose connector is mounted directly on its body), which allows these devices to be connected directly to a headset or radio station to establish wireless communication. In this case, it does not require a lot of power or a large antenna to establish communication.
Some promising technologies include near-field magnetic induction (NFMI). The advantage for the military, Moore said, is that "the likelihood of detecting or intercepting a signal at 10-20 meters is much lower than that of electricity-based systems such as a Bluetooth signal or a standard VHF radio."
Fallon said the NFMI creates a small magnetic field within two meters of the source, increasing security and reliability, and that wireless technology is very promising, although it needs to be improved and secured with encryption.
Tactical headsets offer more options than ever before: improved hearing protection; operation in more severe external conditions; and advanced communication options. Special operations forces traditionally lead in this area, but looking at the continuous process of miniaturization and digitization, it is easy to guess that an increasing number of countries will accept such devices to supply their regular forces.
Currently, the military must, firstly, decide what they really need, and, secondly, make sure that soldiers use and test systems correctly, otherwise they may not be able to get a chance to get qualitatively new advantages on the battlefield.
