To help you pick a set of cordless speakers, I will clarify the term “signal-to-noise ratio” which is commonly used in order to describe the performance of wireless loudspeakers. Once you have chosen a number of wireless loudspeakers, it’s time to explore some of the specs in more detail to help you narrow down your search to one product. The signal-to-noise ratio is a rather key parameter and describes how much noise or hiss the wireless loudspeaker makes. Comparing the noise level of several sets of wireless loudspeakers can be done quite easily. Just gather a number of products that you wish to evaluate and short circuit the transmitter audio inputs. Afterward set the wireless speaker gain to maximum and check the level of noise by listening to the loudspeaker. The noise that you hear is generated by the wireless speaker itself. After that compare different sets of cordless loudspeakers according to the following rule: the lower the amount of noise, the better the noise performance of the cordless speaker. Though, bear in mind that you must put all sets of cordless loudspeakers to amplify by the same level to evaluate different models.
If you prefer a set of cordless speakers with a small amount of hissing, you can look at the signal-to-noise ratio number of the specification sheet. A lot of manufacturers will display this figure. wireless loudspeakers with a high signal-to-noise ratio will output a low amount of hiss. One of the reasons why wireless outdoor speakers sold by Amphony Inc. create noise is the fact that they utilize components including transistors as well as resistors which by nature produce noise. The overall noise depends on how much noise each component generates. Yet, the location of those elements is also essential. Elements which are part of the loudspeaker built-in amplifier input stage will normally contribute the majority of the noise. Static is also brought on by the wireless transmission. Different kinds of transmitters are available which operate at different frequencies. The cheapest sort of transmitters utilizes FM transmission and usually broadcasts at 900 MHz. The level of hiss is also dependent upon the level of cordless interference from other transmitters. Newer models are going to usually employ digital audio transmission at 2.4 GHz or 5.8 GHz. The signal-to-noise ratio of digital transmitters is dependent mostly on the kind of analog-to-digital converters and other components that are utilized as well as the resolution of the cordless protocol. Most today’s cordless loudspeakers have built-in power amps that incorporate a power switching stage which switches at a frequency around 500 kHz. As a result, the output signal of wireless speaker switching amps contain a fairly big level of switching noise. This noise component, however, is generally impossible to hear given that it is well above 20 kHz. Nonetheless, it can still contribute to loudspeaker distortion. Signal-to-noise ratio is generally only shown within the range of 20 Hz to 20 kHz. Thus, a lowpass filter is used when measuring wireless loudspeaker amps to eliminate the switching noise. Manufacturers measure the signal-to-noise ratio by setting the built-in amplifier such that the full output swing can be realized and by feeding a test tone to the transmitter which is usually 60 dB underneath the full scale of the speaker amp. Next, only the hiss between 20 Hz and 20 kHz is considered. The noise at different frequencies is removed by a filter. Then the amount of the noise energy in relation to the full-scale output power is computed and shown in decibel. A different convention in order to state the signal-to-noise ratio makes use of more subjective terms. These terms are “dBA” or “A weighted”. You are going to find these terms in many wireless loudspeaker parameter sheets. In other words, this method tries to state how the noise is perceived by a person. Human hearing is most perceptive to signals around 1 kHz while signals below 50 Hz and above 14 kHz are hardly heard. The A-weighted signal-to-noise ratio is frequently higher than the unweighted ratio and is published in most wireless loudspeaker parameter sheets.