What to Look Out for in Sound Equipment


student with microphone in class










This post will focus on the latest digital technology, feedback management, voice enhanced amplification settings, speaker capacity, and multimedia input features.


Before explaining the aspects to consider when investing in sound equipment, it is important to understand the PA system (Public Address System) components and their functions. PA’s and other sound reinforcement systems consist of: a pickup device such as a microphone to convert sound waves into an electronic signal, an amplifier to boost the weak signal produced by the pickup, and loudspeakers to convert the electrical impulse from the amplifier back into sound waves.


Consider what you need sound equipment for first. A PA system may not have the desired effect that your looking for, especially if you are seeking voice reinforcement. If you are looking for voice reinforcement technology in particular, you may need to look into Soundfield systems and an educational PA.


1. Feedback Management


Feedback is the ringing noise (often described as squealing, screeching, and uncomfortable to the ears) that sometimes occurs in sound systems. It is caused by a “looped signal” of sound. See the example in the diagram below.


A microphone feeds a signal into a sound system, which then amplifies and outputs the signal from a speaker, which is picked up again by the microphone.


noise feedback diagram


There are many situations in which feedback can occur. Feedback is mainly the result of the positioning of the element that produces noise, or the level of sound that the signal produces. To eliminate feedback, one must disrupt the feedback cycle.


Here are a few suggestions for controlling feedback – it is often necessary to try a few of these tips before the feedback issue is identified and solved:


  • Change the position of the microphone and/or speaker so that the speaker output isn’t feeding directly into the mic. Position the microphone behind speakers rather than in front of the speakers.
  • Use a directional microphone (when purchasing a microphone look for one that is bi-directional instead of omni-directional.
  • Speak close to the microphone.
  • Turn your microphone off when not in use.
  • Lower the level of output through the speakers or input of the microphone.
  • Avoid aiming speakers directly at reflective surfaces such as walls.
  • Use headset or in-ear monitors instead of speaker monitors – monitors are the speakers that are used by the person on stage where other speakers face the audience.


2. Voice Enhanced Amplification Settings


The latest school PA systems are designed for maximum operation under adverse conditions, equipped with features such as background noise reduction. Sound for Schools offers an OptiVoice function on its Frontrow systems.


3. Speaker Capacity


As mentioned in our previous post on “Assessing Noise and Reverberation”, a teacher’s voice must be between 10dB to 30 dB higher than background noise in order for children to be attentive and fully comprehend the work that is being explained in their classrooms.


Considering that speakers that are too loud may cause feedback, you don’t want to invest in speakers that are too large. The number of watts you need from your audio speakers depends on the size of your audience, the size of your classroom and what you need amplified. Is it spoken word, recorded sound media or live music?


It is important to recognise that if you connect your speakers to an amplifier the sound level may be boosted drastically despite the fact that your speakers’ wattage is low. The following measure can be used as a rough estimation when selecting your speakers:


Sound Source                  Number of watts (RMS) needed per audience member


Spoken word                                                        0.5 – 1

Acoustic music, solo artists & duos                    2 – 3

Bands at medium sized venues                          3 – 4

Large venues/ loud bands                                   4 – 5


If you have a small to medium classroom you may need to look at something like the Sound For Schools Frontrow Soundfield system range. The Frontrow togo is a excellent portable voice amplification system suitable for small to medium classrooms and meetings.


4. Multimedia Input Features


It is important to look for amplification systems that offer a range of inputs to the received (or amplifier) so that more than one source of sound can be amplified.  Sound for Schools offer a range of multi channel PA systems that are portable too! Auxiliary inputs are a must have and these days it is handy to have sound equipment with USB inputs as many electronic devices such as mp3 players and USB storage devices require USB input ports to transfer data to your PA.


5. Other Factors to Consider


  • Music amplification requires a system that covers a wider range of audio frequencies than speech.
  • Music reproduction requires more wattage.
  • Music sounds best in stereo whereas a mono system works perfectly for speech.
  • More speakers will make your music sound better.
  • Prestige events require a sound system that is both unobtrusive and visually pleasing
  • The portability of a PA system is a cost and effort saving feature.
  • Consider the potential for expanding your PA system in the future
  • The price of a PA system becomes more expensive as the power and number of features increase.


We hope that you found this article helpful in explaining the various factors to consider when deciding to invest in classroom audio technology. For further assistance on choosing the right equipment for your classroom call 020 8772 2700 or send a mail to info@pcwerth.co.uk .

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