Are you searching to buy a brand new a pair of [http://www.amphony.com/products/wireless-speaker.htm wireless speakers for a mac] for your home? You may be dazzled by the amount of choices you have. To make an informed choice, it is best to familiarize yourself with popular terms. One of these terms is called "signal-to-noise ratio" and is not often understood. I am going to help clarify the meaning of this term. Whilst looking for a pair of cordless loudspeakers, you first are going to check the cost, wattage among additional fundamental criteria. Yet, after this initial selection, you are going to still have several products to choose from. Next you will concentrate more on a number of of the technical specs, including signal-to-noise ratio as well as harmonic distortion. One important criterion of wireless speakers is the signal-to-noise ratio. To put it simply, the signal-to-noise ratio explains how much hum or hiss the speakers are going to add to the audio signal. This ratio is customarily shown in decibel or "db" for short.
You can perform a simple assessment of the wireless loudspeaker hiss by short circuiting the transmitter input, setting the loudspeaker gain to maximum and listening to the speaker. The hiss that you hear is generated by the cordless speaker itself. Make certain that the gain of each pair of cordless speakers is pair to the same amount. Otherwise you will not be able to objectively evaluate the amount of hiss between several models. The general rule is: the smaller the amount of noise which you hear the better the noise performance.
In order to help you compare the noise performance, wireless loudspeaker makers publish the signal-to-noise ratio in their cordless loudspeaker specification sheets. Simply put, the larger the signal-to-noise ratio, the lower the level of noise the cordless loudspeaker generates. One of the reasons why cordless loudspeakers produce noise is the fact that they use components including transistors and resistors which by nature produce noise. Typically the elements which are situated at the input stage of the built-in power amp are going to contribute most to the overall hiss. Therefore producers usually are going to choose low-noise elements whilst developing the cordless speaker amplifier input stage. A further cause of noise is the cordless audio broadcast itself. Generally types that employ FM type transmission at 900 MHz are going to have a rather large amount of noise. Other cordless transmitters are going to interfer with FM type transmitters and cause further hiss. Therefore the signal-to-noise ratio of FM style cordless loudspeakers varies depending on the distance of the loudspeakers from the transmitter in addition to the level of interference. To steer clear of these problems, newer 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 depends mostly on the kind of analog-to-digital converters and other parts that are used in addition to the resolution of the cordless protocol. The majority of modern wireless loudspeakers have built-in power amplifiers that include a power switching stage which switches at a frequency around 500 kHz. This switching frequency is also noise which is part of the amplified signal. Yet, latest cordless loudspeakerspecifications generally only consider the hiss between 20 Hz and 20 kHz.
The most widespread technique for measuring the signal-to-noise ratio is to set the cordless speaker to a gain that permits the maximum output swing. Next a test signal is input into the transmitter. The frequency of this tone is usually 1 kHz. The amplitude of this signal is 60 dB underneath the full scale signal. Next the noise-floor energy is measured in the frequency range between 20 Hz and 20 kHz and compared with the full scale signal energy.
Often the signal-to-noise ratio is expressed in a more subjective manner as "dbA" or "A weighted". In other words, this technique tries to express how the noise is perceived by a person. Human hearing is most sensitive to signals around 1 kHz while signals under 50 Hz and higher than 14 kHz are barely noticed. For that reason an A-weighting filter will amplify the noise floor for frequencies which are easily perceived and suppress the noise floor at frequencies that are barely heard. A lot of cordless loudspeaker will have a higher A-weighted signal-to-noise ratio than the un-weighted ratio.
