Written by John Ellis,

You’re using high quality microphones in an acoustically treated boardroom, so in theory you should have the best conference sound available. So why are you still not able to hear the person on the far end of a video conference call clearly? It may be due to the placement of your ceiling loudspeakers.

Video conferencing has become a critical business tool for connecting you with your colleges and clients across the globe. Collaboration and meeting productivity is only achieved when each member of the meeting can be heard and can hear everyone consistently clearly. Proper loudspeaker selection and placement has a great affect on this experience.

Ceiling speakers in boardrooms are often found dotted along the ceiling sporadically, living in spaces that are not already occupied by HVAC, lighting and fire alarm equipment. There may only be a pair of speakers installed in the middle of a very long boardroom table. It is no wonder that the people at the either end of table are complaining that the voices at the far end of the call are muffled and muddy.

There are simple tools that will help you determine the proper placement of ceiling speakers to ensure everyone can properly hear the far end with the best speech intelligibility. A meeting room is only as good as the sum of its parts and better conferencing sound is only achieved when microphones, acoustics and loudspeaker placement are considered equally.

John Ellis from the Shure UK Systems Group explains that there needs to be more attention paid to proper loudspeaker placement to get the best performance: “When designing a new meeting space, video conferencing suite or huddle room, it is important to consider the dispersion pattern of the ceiling loudspeakers you are using.  Most ceiling speakers have a dispersion pattern between 90 – 100 degrees conical, which isn’t very wide when its only 2.8 metres above floor level. This distance is fine if you are directly underneath the speaker, but if you are a few metres off axis it will become difficult to hear the high frequencies of the speaker’s voice and their audio will sound muffled and hard to hear clearly. If the correct amount of loudspeakers are not installed in the right positions to cover the room you may have some areas that are very loud and some that are soft; some areas will have more bass and less HF, depending on how bright the room is. Audio below 200 hertz is omnidirectional and as the sound travels up towards higher frequencies the dispersion gets a lot narrower. So off axis the high frequencies roll off before low frequencies which will result in a loss in speech intelligibility and detail to those areas that are not under the loudspeaker.

If the system chosen is reliable, easy to use and a time saving tool, employees are more likely to embrace it rather than shy away from using it. We’ve all been in a situation where we’ve walked into a meeting room, attempted to start a call only for the technology to fail us. In an internal meeting this is frustrating and time consuming; for a client meeting it is unprofessional and creates a poor first impression. Employees need equipment they can rely on. If they’re struggling to speak to colleagues or gather information they can end up feeling isolated or unable to carry out the intended tasks. Not only that, but offering flexible working and showing an awareness of an individual’s situation can make staff feel more valued, increasing loyalty to the business and thus boosting retention rates, creating a clear business benefit.

While mobiles and messaging still have their place in business, a strong and complete unified communications strategy will benefit your business in a number of ways; by ensuring you can maintain productivity and communication, helping you to retain employees, offering flexibility and agility to a workforce that is increasingly demanding new ways of working, and making sure the business is able to adapt to external events more quickly. Remote workers will be able to access to the same functionality as their office-based colleagues without the hassle of trying to commute during industrial action and, crucially, business continuity will be maintained if a more serious unexpected event occurs.

Lower ceiling heights equate to speakers with less coverage in the room, which will create hot and cold spots of strong and weak sound, respectively. Thus, more loudspeakers will be required for good coverage, which could be smaller units. John explains that there is an easy way to solve this problem: “EASE Address (http://address.afmg.eu/) is a free software application that will help you determine the best placement of your loudspeakers based on the size of the room, the ceiling height and the number of chairs around the table. All manufactures should provide EASE data with their ceiling speakers. The software will give you the loudspeaker coverage areas in two dimensions and show the hot and cold zones in the room.

John also explains that it is important to choose the proper ceiling speaker for the job: “Many of the inexpensive ceiling speakers are designed for corridors or office for basic paging audio, not high quality speech or music applications. Just recently I was in a high-end boardroom, yet looking in the ceiling the speakers were low quality open backed unit. All ceiling loudspeakers should be fully enclosed with back cans that are usually fire rated. This stops dust and dirt ingress, improves sound quality, stops the speakers from rattling or vibrating the ceiling and maintains the fire rating of the ceiling.

“Poor loudspeaker placement can effect that quality of the room’s echo reduction and acoustic Echo Cancellation processing. If you have microphones under a loudspeaker and others off axis, with improper coverage, the signal will not effectively trigger the AEC so that it can determine the appropriate sounds to cancel and mute. Furthermore, this also ties into the argument of using high quality mics for enhanced video conferencing intelligibility.”

John Ellis

John Ellis is a Regional Sales Manager for the Shure UK Systems Group. When he is not out meeting with London’s top AV integrators and consultants, you will find him demonstrating the finest modern jive dance steps this side of the Thames.