It is easy to be puzzled by the language which cordless speaker manufacturers employ to explain the performance of their products. I am going to clarify the meaning of one commonly used specification: “signal-to-noise ratio” in order to help you make an informed decision while purchasing a new a pair of wireless loudspeakers. As soon as you have chosen a number of wireless loudspeakers, it’s time to explore several of the specifications in more detail in order to help you narrow down your search to one product. Each cordless loudspeaker will make a certain level of hiss and hum. The signal-to-noise ratio will help calculate the level of noise created by the loudspeaker.
You can perform a simple comparison of the cordless loudspeaker hiss by short circuiting the transmitter input, setting the loudspeaker volume to maximum and listening to the loudspeaker. You will hear some amount of hissing and/or hum coming from the loudspeaker. This noise is produced by the wireless speaker itself. Then compare several sets of wireless loudspeakers according to the next rule: the lower the amount of hiss, the higher the noise performance of the wireless loudspeaker. Yet, bear in mind that you have to set all sets of cordless speakers to amplify by the same amount to compare several models. Whilst glancing at the wireless loudspeaker spec sheet, you want to look for a set of wireless loudspeaker with a large signal-to-noise ratio number which suggests that the cordless loudspeakers (Learn regarding wireless outdoor speaker systems) output a small amount of noise. Noise is generated due to a number of factors. One factor is that today’s cordless loudspeakers all utilize elements like transistors as well as resistors. Those elements are going to produce some amount of hiss. Typically the components that are located at the input stage of the built-in power amplifier are going to contribute most to the overall noise. Thus suppliers usually will choose low-noise components whilst developing the cordless speaker amplifier input stage. Noise is also created by the wireless broadcast. Different types of transmitters are available which work at different frequencies. The least expensive sort of transmitters makes use of FM transmission and usually broadcasts at 900 MHz. Other wireless transmitters will interfer with FM type transmitters and result in further static. For that reason the signal-to-noise ratio of FM style cordless loudspeakers varies depending on the distance of the speakers from the transmitter in addition to the level of interference. To steer clear of these problems, modern transmitters make use of digital audio broadcast and generally transmit at 2.4 GHz or 5.8 GHz. The signal-to-noise ratio of digital transmitters is dependent by and large on the kind of analog-to-digital converters and other components that are utilized as well as the resolution of the wireless protocol. The majority of of today’s cordless speaker use amplifiers which are based on a digital switching architecture. These amplifiers are referred to as “class-D” or “class-T” amplifiers. Switching amplifiers incorporate a power stage which is constantly switched at a frequency of around 400 kHz. This switching frequency is also hiss that is part of the amplified signal. Yet, today’s cordless loudspeakerspecifications generally only consider the noise between 20 Hz and 20 kHz. Manufacturers measure the signal-to-noise ratio by means of setting the built-in amplifier such that the full output swing may be realized and by inputting a test signal to the transmitter which is normally 60 dB below the full scale of the loudspeaker amplifier. Next the noise-floor energy is calculated in the frequency range between 20 Hz and 20 kHz and compared with the full scale signal energy.
Often you will find the expression “dBA” or “a-weighted” in your wireless speaker spec sheet. A weighting is a method of showing the noise floor in a more subjective fashion. In other words, this technique attempts to state how the noise is perceived by a human being. Human hearing is most sensitive to signals around 1 kHz while signals under 50 Hz and above 14 kHz are hardly heard. Therefore an A-weighting filter is going to amplify the noise floor for frequencies which are easily perceived and suppress the noise floor at frequencies that are hardly perceived. Most wireless speaker are going to show a larger A-weighted signal-to-noise ratio than the un-weighted ratio. Find even more reading at http://www.necn.com/08/27/13/Sending-a-new-generation-of-kids-off-to-/landing_features.html?blockID=850717.