By Full Compass LiveBy Chris Lyons, Shure
While the microphone converts sound into an electrical signal, the loudspeaker converts a signal back into sound. In the context of meeting rooms used for training seminars or AV conferencing, ceiling speakers are often thought of only in terms of their size, sound level, and coverage area. The growing trend, however, is toward networked speakers that offer more advanced capabilities and time-saving features.
Loudspeaker Sound Quality
Of course, the ceiling speaker’s fundamental job is first and foremost to reproduce speech clearly. But modern AV conferencing spaces increasingly include a wider spectrum of multimedia content, making it essential that the loudspeaker can handle music and other sounds in addition to speech. A two-way driver is often required, with frequency responseDefinition:
The range of frequencies that an audio, video or data device can pass. that is optimized for voice intelligibility yet with enough range to sound pleasing with a variety of program sources.
Amplification
Every loudspeaker needs an amplifierDefinition:
1. A device that increases the voltage or power of a signal. 2. In music performance, a device such as a guitar amplifier that includes speakers and controls to increase the sound level of acoustic or electric instruments., but power amps carry a load of installation baggage: they take up space, they need ACDefinition:
(Alternating Current): Current whose electrical flow alternates between positive and negative quadrants, and whose magnitude varies periodically. Alternating current is used in most commercial power transmission, and is also the basis of audio or video signals. power, and they generate heat. A DanteDefinition:
Dante™ (Digital Audio Network Through Ethernet): The audio-over-IP standard created by Audinate (layer 3). speaker, on the other hand, includes an integrated amplifierDefinition:
A combination of a preamplifier and power amplifier in the same chassis., and can be powered by PoEDefinition:
(Power over Ethernet): Voltage over Ethernet cables to power remote equipment without needing a separate power supply, up to a maximum output of 15.4 Watts. or PoE+ over the same network cable that carries the audio signal. Using self-powered speakers eliminates the need for power amplifiers altogether. A PoE speaker can produce more than adequate sound pressure levels for typical AV conferencing applications, but on some models upgrading to PoE+ may deliver a significant boost in output level for rooms where slightly higher volume is desired.
Signal Routing
In most meeting rooms, traditional ceiling loudspeakers rely on a dedicated connection from the amplifier, and the amplifiers are all fed the same audio stream from an output on the audio mixer. Networked loudspeakers can take their signal from any point on the audio network, which provides vastly greater control over signal routing. Also, eliminating the amplifiers also eliminates the need to adjust the signal levels between the mixer output and amplifier input, and the amplifier output and loudspeaker input.
DSP Utilities
Ceiling loudspeakers are often thought of as passive devices that simply reproduce whatever signal they’re given, but they can be active contributors to the sound of the audio system. Even with comprehensive audio processing in a mixer or digital signal processor, it is often desirable to apply some additional processing that relates to the loudspeakers in one part of the room or even to an individual loudspeaker. With networked loudspeakers, the cost and time of synchronizing external stand-alone DSPDefinition:
1. (Digital Signal Processor): An integrated circuit or device that mathematically alters sound or video signals. 2. (Digital Signal Processing): The technique of converting an analog signal into digital data, manipulating that data, then producing an analog output that reflects the changes caused by these manipulations done in the digital domain. products is eliminated, especially when combined with microphones like the MXA910 with IntelliMix® which also has built in DSP.
Equalization (EQ) can help to correct for sound reflections caused by nearby walls, for example. Digital delayDefinition:
A device that outputs and input signal some time later. This can be short for echo effects, longer for matching speaker stacks, or aligning sound and video. helps to align and connect lip sync with a video feed so that the presenter’s audio and movements are in line and not disjointed. A limiterDefinition:
A form of compressor with a ratio of infinity:1 above the threshold for both overload protection, or as a sound effect to normalize volume. Some engineers consider a compressor with a ratio of 20:1 or higher above the threshold for a limiter. can prevent the sound level from exceeding a prescribed maximum in the presence of extreme signal variations. Finally, a signal or tone generator is an enormous time-saver when the system is being dialed in, both to verify signal paths, identify speakers, and confirm proper installation.
Audio Security
Dante-enabled loudspeakers carry the added potential for the audio connection to feature enhanced security. In the case of Shure Audio EncryptionDefinition:
Scrambling a signal, which requires decoding to decipher., this extends security from the microphone at one end of the audio chain to the loudspeaker at the other end in the room, which is an appealing benefit to clients who are particularly concerned with the privacy of meeting content. This prevents unauthorized persons from accessing the audio stream through the loudspeaker connection.
Remote Management
No matter how advanced or high-tech a sound system may be, the ongoing functioning of loudspeakers needs to be checked periodically like every other component in the system. Networked loudspeakers offer the added benefit of remote management. Audio management software can verify that each loudspeaker is operating normally, and send a message to a technician when a speaker goes offline or otherwise needs attention. This way, time is only spent on solving actual problems instead of constantly checking to see if problems exist.
The ceiling loudspeaker has gone from being under appreciated and overlooked to being a full-fledged member of the audio ecosystem. With network connectivity and a flexible configuration tools, loudspeakers are ready to do more than just making the sound – they can make the sound everything it should be.
Read the other articles highlighting the Microflex Ecosystem for AV Conferencing:
- The Microflex Ecosystem, Part 1: Conferencing Microphones
- The Microflex Ecosystem, Part 2: Digital Signal Processing
- The Microflex Ecosystem, Part 4: Conferencing Software
Shure Microflex Advance array microphones combine adjustable pickup lobes, internal DSP, and simple configuration in a variety of ceiling, wall, or table mounting options. For a free consultation, call our trained and certified product experts at 800-356-5844. Learn more at https://www.fullcompass.com/promos/shure-microflex-conferencing-solutions.
Republished with permission from Shure Incorporated.
