First let’s talk about what FM and IR actually are.

Both of these different frequencies of wave transmission. The electromagnetic spectrum has a wide range of different frequencies, and each frequency has a unique wavelength size.

Frequency (Hz) 1010 – 108 1011 1013 1014 1015 1017 1019
Type Radio Microwave Infrared Visible Ultraviolet X-Ray Gamma Ray


FM is a type of radio frequency, so it has a relatively small frequency. IR means infrared frequency, so FM Transmittersslightly higher in frequency than radio. Both of these types of transmission have higher frequencies and lower wavelengths than visible light, and this is why we can’t see them. So, these frequencies can transmit signals like sound through air or even solid objects in the case of radio without us ever seeing the transmission. This is why this technology is the most often used interpretation equipment. These methods can even work across multiple frequencies so they can be used as multiple language transmitters for multilingual events.

So IR has a higher frequency than FM, but which should I choose?

So now that we know the meaning of these terms, let’s talk about which type of transmission is preferable in different situations. To pick, ask yourself these questions:

Do I need a transmission system that is secure and private?

Say your event contains sensitive information, and you do not want the signal to leave the area of the meeting or even be contained within the walls of a room. In this case, IR transmission will be the better option. The signal does not have as wide a range as FM signals, and it cannot pass through opaque objects like walls. Keep in mind, things like chairs, podia, and other solid objects can also block IR waves, so be sure to have a clear line of sight between transmitter and receiver.

Do I need a transmission system that can cover a wide area?

If you are looking for a sound system that has the capability to transmit the sound signal throughout a large venue, including a large outdoor event, then FM transmitters will likely serve your purposes better. Again, IR does not have a very long range of transmission, and it can be easily blocked by things like trees or poles. FM will transmit a signal much farther than IR.

Is my event outdoors?

In general, FM transmission is preferable for outdoor events for a few reasons. First, it can span a much larger area than IR. Another reason why FM is better for outdoor use is that IR transmissions can receive interference from the visible light that comes from the sun. So, if your sound system needs to function in a bright, outdoor environment, FM is most likely the way to go.

How important is a consistent, reliable signal?

A drawback of FM transmission is the possibility of interference from other radio sources. So, if consistency and reliability of your signal is very important to you, IR transmission can provide this type of assurance. In addition, IR signals sync much more effectively than FM signals, so there is an added level of reliability.

Do I need a system that is easy to set up and run?

Another benefit of FM transmission systems is that they are fairly simple to set up, install, and run. IR transmission systems typically require a professional installer, and they require more equipment than FM systems to cover the same amount of area.

We’d love to hear about your experience with these types of transmission systems! Which do you prefer? Answer in the comments below!