To help you decide on a set of cordless loudspeakers, I am going to describe the term "signal-to-noise ratio" which is usually used to describe the performance of cordless loudspeakers.
When you have narrowed down your search by taking a look at several fundamental criteria, including the amount of output wattage, the dimensions of the loudspeakers plus the cost, you are going to still have quite a few models to choose from. Now it is time to look at some of the technical specifications in more detail. The signal-to-noise ratio is a rather vital parameter and describes how much noise or hiss the wireless loudspeaker creates.
A way to do a simple test of the noise performance of a set of wireless speakers is to short circuit the transmitter audio input and then to crank up the cordless loudspeaker to its maximum. Then listen to the loudspeaker. Usually you will hear 2 components. The first is hissing. In addition, you are going to often hear a hum at 50 or 60 Hz. Both of these are components which are produced by the cordless speaker itself. After that compare different sets of cordless loudspeakers according to the following rule: the lower the level of static, the higher the noise performance of the wireless loudspeaker. Yet, bear in mind that you must put all sets of cordless loudspeakers to amplify by the same amount to evaluate several models.
In order to help you evaluate the noise performance, wireless speaker suppliers publish the signal-to-noise ratio in their cordless loudspeaker spec sheets. Simply put, the larger the signal-to-noise ratio, the lower the amount of noise the wireless loudspeaker produces. There are numerous reasons why wireless loudspeakers are going to add some form of hiss or other unwanted signal. Transistors and resistors which are part of every modern cordless loudspeaker by nature generate noise. The overall noise is dependent on how much hiss each element generates. Nonetheless, the location of these components is also essential. Components that are part of the speaker built-in amp input stage will normally contribute most of the noise.
Hiss is also caused by the cordless broadcast. Different types of transmitters are available which work at different frequencies. The most inexpensive type of transmitters employs FM transmission and typically broadcasts at 900 MHz. Other cordless transmitters will interfer with FM type transmitters and bring about further hiss. Therefore the signal-to-noise ratio of FM style wireless loudspeakers varies depending on the distance of the speakers from the transmitter and the level of interference. To steer clear of these problems, newer transmitters employ digital music transmission and usually broadcast at 2.4 GHz or 5.8 GHz. The signal-to-noise ratio of digital transmitters depends by and large on the kind of analog-to-digital converters and other components that are utilized along with the resolution of the wireless protocol.
Most of recent wireless speakers use power amplifiers which are digital, also called "class-d amps". Class-D amps utilize a switching stage which oscillates at a frequency between 300 kHz to 1 MHz. Consequently, the output signal of cordless speaker switching amplifiers contain a rather large level of switching noise. This noise component, however, is generally impossible to hear as it is well above 20 kHz. Though, it may still contribute to loudspeaker distortion. Signal-to-noise ratio is usually only shown within the range of 20 Hz to 20 kHz. Therefore, a lowpass filter is utilized while measuring wireless speaker amps in order to remove the switching noise.
The most popular method for measuring the signal-to-noise ratio is to pair the wireless loudspeaker to a gain that enables the maximum output swing. Then a test signal is fed into the transmitter. The frequency of this tone is generally 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 you are going to discover the term "dBA" or "a-weighted" in your cordless loudspeaker specification sheet. A weighting is a method of expressing the noise floor in a more subjective fashion. In other words, this method tries to state how the noise is perceived by a human. Human hearing is most perceptive to signals around 1 kHz while signals under 50 Hz and above 14 kHz are barely noticed. The A-weighted signal-to-noise ratio is usually larger than the unweighted ratio and is published in the majority of cordless loudspeaker parameter sheets.
When you have narrowed down your search by taking a look at several fundamental criteria, including the amount of output wattage, the dimensions of the loudspeakers plus the cost, you are going to still have quite a few models to choose from. Now it is time to look at some of the technical specifications in more detail. The signal-to-noise ratio is a rather vital parameter and describes how much noise or hiss the wireless loudspeaker creates.
A way to do a simple test of the noise performance of a set of wireless speakers is to short circuit the transmitter audio input and then to crank up the cordless loudspeaker to its maximum. Then listen to the loudspeaker. Usually you will hear 2 components. The first is hissing. In addition, you are going to often hear a hum at 50 or 60 Hz. Both of these are components which are produced by the cordless speaker itself. After that compare different sets of cordless loudspeakers according to the following rule: the lower the level of static, the higher the noise performance of the wireless loudspeaker. Yet, bear in mind that you must put all sets of cordless loudspeakers to amplify by the same amount to evaluate several models.
In order to help you evaluate the noise performance, wireless speaker suppliers publish the signal-to-noise ratio in their cordless loudspeaker spec sheets. Simply put, the larger the signal-to-noise ratio, the lower the amount of noise the wireless loudspeaker produces. There are numerous reasons why wireless loudspeakers are going to add some form of hiss or other unwanted signal. Transistors and resistors which are part of every modern cordless loudspeaker by nature generate noise. The overall noise is dependent on how much hiss each element generates. Nonetheless, the location of these components is also essential. Components that are part of the speaker built-in amp input stage will normally contribute most of the noise.
Hiss is also caused by the cordless broadcast. Different types of transmitters are available which work at different frequencies. The most inexpensive type of transmitters employs FM transmission and typically broadcasts at 900 MHz. Other cordless transmitters will interfer with FM type transmitters and bring about further hiss. Therefore the signal-to-noise ratio of FM style wireless loudspeakers varies depending on the distance of the speakers from the transmitter and the level of interference. To steer clear of these problems, newer transmitters employ digital music transmission and usually broadcast at 2.4 GHz or 5.8 GHz. The signal-to-noise ratio of digital transmitters depends by and large on the kind of analog-to-digital converters and other components that are utilized along with the resolution of the wireless protocol.
Most of recent wireless speakers use power amplifiers which are digital, also called "class-d amps". Class-D amps utilize a switching stage which oscillates at a frequency between 300 kHz to 1 MHz. Consequently, the output signal of cordless speaker switching amplifiers contain a rather large level of switching noise. This noise component, however, is generally impossible to hear as it is well above 20 kHz. Though, it may still contribute to loudspeaker distortion. Signal-to-noise ratio is usually only shown within the range of 20 Hz to 20 kHz. Therefore, a lowpass filter is utilized while measuring wireless speaker amps in order to remove the switching noise.
The most popular method for measuring the signal-to-noise ratio is to pair the wireless loudspeaker to a gain that enables the maximum output swing. Then a test signal is fed into the transmitter. The frequency of this tone is generally 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 you are going to discover the term "dBA" or "a-weighted" in your cordless loudspeaker specification sheet. A weighting is a method of expressing the noise floor in a more subjective fashion. In other words, this method tries to state how the noise is perceived by a human. Human hearing is most perceptive to signals around 1 kHz while signals under 50 Hz and above 14 kHz are barely noticed. The A-weighted signal-to-noise ratio is usually larger than the unweighted ratio and is published in the majority of cordless loudspeaker parameter sheets.
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