Bring your audience back from the dead
As a public speaker, there is nothing worse than a comatose gaze from the audience that says they have no idea what you are talking about. You are speaking. Your audience is present, but it’s as if they are on the other side of an anti-communication force field. Meanwhile, you find your internal dialog rudely interjecting with all kinds of unhelpful notions:
- These people are asleep with their eyes open
- They can’t even hear you
- Your microphone is turned off
- Your zipper is down
To be honest, there is a percentage of the audience who CAN’T hear you. It’s not because they don’t want to. Some people suffer from hearing impairment. At other times, poor room acoustics can convert your entire audience into unhearing zombies who only watch your lips move and wonder why no words are coming out.
Fortunately for us, an assistive listening system can cut through the conversation killing challenges and make the difference between getting blank stares and getting your point across.
What is assistive listening?
An assistive listening device (ALD) is an electronic accessory that facilitates the clear perception of audio content such as lectures, sermons or concerts. While ALDs are used by people who are hearing impaired, useful applications reach much further. Some of the critical applications include:
- A listening aid for the hearing impaired
- A device that ensures clarity in settings that have less than ideal acoustics such as excessive reverb or high background noise
- Situations where a speech or discussion must be translated to different languages in real time
- Description services for the blind
It is important to note that although ALDs meet a critical need in the world of audio communication, no ALD has ever been invented that will allow children to clearly hear an adult’s voice when they are told to clean their room. More research is apparently needed.
Regardless of the substance or function your communication carries, it’s a safe assumption that you need the audience to understand what is being said. There is nothing worse than having a willing audience that you cannot communicate with. When the audience can clearly hear and understand, effectiveness in communication goes up.
Different transmission types
Most ALDs function as an add-on to an existing sound system, but there are choices for situations where no sound system is present. Your sound engineer that manages the use of broadcast speakers will route an audio signal from the sound source, be it a microphone or other audio feed, to the broadcast unit in your ALD system. Audio content wirelessly transmits to all matching receivers within range. Choosing the particular transmission method is a critical step in the purchase and installation of an effective ALD system. Let’s take a look at a few of the most common transmission methods and the strengths and weaknesses of each:
- An FM wireless system is by far the most common on this list. FM radio technology has been in use for a long time. This means it has had time to become reliable and cost effective. FM systems beat all others when it comes to cost. Installation is usually pretty simple with the added bonus of portability if needed. For permanent installations, an RF system can be hidden out of view while still transmitting properly. Most RF systems can cover a large seating area quite easily. Amongst all of the great features an RF system offers, there are a few situations where they may not be the best choice. In some environments, RF interference may cause colorful CB radio conversations to embellish your Sunday morning sermon with untimely expletives. Another important item to note is that RF systems do not offer privacy. Anyone with a properly tuned receiver may be able to listen in on broadcasts. As an example: courtroom applications should not use FM radio as the transmission method.
- Infrared systems tend to offer a bit more security when it is needed. This is because transmissions are in the form of invisible light. While RF can pass through walls, infrared light waves can not. When considering the particular needs of your ALD system, infrared is a great solution for environments that have excessive RF interference. Infrared systems can be a bit more finicky when it comes to transmitting to all associated listening devices. Architectural features of a room can block these invisible light waves from reaching a receiver. Dark carpets may absorb transmissions rather than reflecting them further into the room. Infrared may not be the choice for outdoor venues as direct sunlight will interfere with transmissions. Since most infrared systems will need approximate line of sight between the transmitter and its receivers, the transmitter cannot be hidden away in a separate room. It is worth noting that a good deal of personal television ALDs operate through infrared transmission.
- Induction loop systems, also called “loop systems”, are well used and offer some unique benefits that other methods do not. The main benefit of a loop system is that it can transmit directly to a “T-coil” equipped hearing aid. By default, this means that this system can be used more discreetly as most hearing aids are designed to be as invisible as possible. Of course, you will need to keep some receivers on hand for users who do not have a capable hearing aid. A loop system is suitable for small to medium sized rooms. The cost of installation shoots up pretty fast when covering larger areas. The reason for this increased cost of installation is the cable that must be installed strategically to allow magnetic transmission through the room. Loop systems are known for not having extremely high fidelity as a feature. In the right setting, this transmission method is extremely convenient for the audience.
- Digital transmission via the 2.4 gig band offers high definition performance. Digital systems are generally best for small to medium size rooms and can easily be portable. In most places around the world, no RF license is required to broadcast on the 2.4 gig band. Keep in mind that this particular band is the same range as wireless internet routers and a few other wireless systems. This can infrequently cause interference between devices. Receivers for this kind of a system can vary from dedicated receivers to systems that use the consumer’s smartphone for picking up a broadcast. While these different systems both use the 2.4 gig band, they really are two completely different animals. One choice offers discrete hardware while others may only require that the listener have an application for their smartphone.
Examples of complete systems
Now that we have considered the different kinds of systems that may work for you, let’s make this discussion more practical by checking out some examples of ALD systems to meet your particular needs:
- Starting with the ever popular RF transmission method, the Williams Sound PPA-VP37 is a complete system with a transmitter and four receivers. The PPA-VP37 is capable of broadcasting on one of 17 different channels. If interference is encountered on a particular channel, simply choose a different one for interference free operation. The transmitter touts a range of 1000 feet.
- If you are equipping a smaller area and only need a range of 600 feet, the Listen Technologies LP-3CV-072 system costs a bit less than the above mentioned PPA-VP37 but still comes with a transmitter and four receivers. There are three different transmission channels to choose from for side stepping RF interference. As with most RF systems, if the need arises to serve more than four listeners at a time, additional receivers can be seamlessly integrated into the same system.
- For the security that an infrared transmission system provides, look into the Williams Sound WIR SYS 7522. This kit includes one infrared transmitter that is capable of covering up to 5000 square feet and three receivers with headphones as well as two neck loops that receive audio signals and retransmit to T-coil equipped hearing aids. Additional receivers can always be purchased. Infrared repeaters can also be added to the system to cover more area.
- Williams Sound also offers a modest inductive loop system in the PLA DL 210 SYS1 kit. The included induction loop amplifier can accommodate one perimeter loop or multiple loops as well as a mix of one loop and one loudspeaker. This amplifier also includes DSP capabilities such as EQ, compression, loop phase shift and more. Keep in mind that having two receivers does not limit you to two listeners. Scores of additional users can listen in via their T-coil equipped hearing aids.
- In keeping with modern times, the Listen Technologies PLS-900-04-A1 is a system that streams four channels of audio directly to any user’s smart phone. This system is perfect for deployment at a sports bar where there are multiple screens in use at the same time. Up to 60 users can log on to the system simultaneously, and the number of audio streams can be upgraded to a maximum of 24. Each of the audio channels can be assigned a custom name for an easier user experience. It is worth noting that the fidelity of the PLS-900 is the same as a CD.
- For a personal system that is designed to be portable and easy to use, check out the Listen Technologies LS05-072 personal assistive listening system. Both the transmitter and receiver are battery powered. This system is geared toward the individual user who wants to take matters into his own hands.
As you decide on the particular assistive listening system that will meet your needs, be sure to make the decision with a series of questions about range, number of listeners and privacy. These particular questions will make a seemingly complex choice quite easy.
Now go tell the world
Now that you are armed with the tools for reaching 100% of your audience, zip up that fly and deliver the message that they all need to hear.