Are you searching to acquire a new a pair of cordless speakers for your home? You might be dazzled by the amount of choices you have. In order to make an informed choice, it is best to familiarize yourself with popular terms. One of these terms is named "signal-to-noise ratio" and is not frequently understood. I am going to help explain the meaning of this term.
When you have narrowed down your search by looking at some basic criteria, like the amount of output wattage, the size of the speakers and the price, you are going to still have quite a few models to choose from. Now it is time to look at a few of the technical specs in more detail. Every wireless speaker is going to make a certain amount of hiss and hum. The signal-to-noise ratio is going to help quantify the level of noise created by the speaker.
One technique to perform a straightforward check of the noise performance of a pair of cordless speakers is to short circuit the transmitter audio input and then to crank up the cordless speaker to its maximum. Next listen to the loudspeaker. Typically you will hear 2 components. The first is hissing. In addition, you will regularly hear a hum at 50 or 60 Hz. Both of these are components which are produced by the cordless loudspeaker itself. Next compare several sets of cordless loudspeakers according to the following rule: the smaller the amount of hiss, the better the noise performance of the cordless loudspeaker. On the other hand, keep in mind that you must set all sets of wireless speakers to amplify by the same amount to compare several models.
To help you evaluate the noise performance, cordless speaker suppliers publish the signal-to-noise ratio in their cordless speaker spec sheets. Simply put, the higher the signal-to-noise ratio, the lower the level of noise the wireless speaker creates. One of the reasons why cordless loudspeakers produce noise is the fact that they use elements such as transistors as well as resistors which by nature produce noise. The overall noise is dependent on how much noise each component generates. Yet, the location of these elements is also vital. Components which are part of the loudspeaker built-in amp input stage are going to usually contribute most of the noise.
One more cause of hiss is the cordless music broadcast itself. Usually models that utilize FM type transmission at 900 MHz will have a fairly large amount of noise. The amount of static is also dependent upon the level of wireless interference from other transmitters. Newer models will usually utilize digital music broadcast 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 as well as the resolution of the cordless protocol.
A lot of of today's cordless speaker use amplifiers which are based on a digital switching topology. These amplifiers are named "class-D" or "class-T" amplifiers. Switching amplifiers include a power stage that is constantly switched at a frequency of around 400 kHz. As a result, the output signal of wireless speaker switching amps exhibit a moderately big amount of switching noise. This noise component, though, is usually inaudible because it is well above 20 kHz. On the other hand, it may still contribute to speaker distortion. Signal-to-noise ratio is usually only shown within the range of 20 Hz to 20 kHz. For that reason, a lowpass filter is used when measuring wireless speaker amps to remove the switching noise.
The most popular technique for measuring the signal-to-noise ratio is to couple the wireless speaker to a gain which allows the maximum output swing. Then a test signal is input into the transmitter. The frequency of this signal is typically 1 kHz. The amplitude of this signal is 60 dB below the full scale signal. Then, only the hiss between 20 Hz and 20 kHz is considered. The noise at different frequencies is removed by a filter. Next the amount of the noise energy in relation to the full-scale output power is computed and shown in decibel.
Time and again the signal-to-noise ratio is shown in a more subjective method as "dbA" or "A weighted". This method was developed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most responsive to signals around 1 kHz. However, signals under 50 Hz and above 13 kHz are barely noticed. An A-weighted signal-to-noise ratio weighs the noise floor according to the human hearing and is usually larger than the unweighted signal-to-noise ratio.
When you have narrowed down your search by looking at some basic criteria, like the amount of output wattage, the size of the speakers and the price, you are going to still have quite a few models to choose from. Now it is time to look at a few of the technical specs in more detail. Every wireless speaker is going to make a certain amount of hiss and hum. The signal-to-noise ratio is going to help quantify the level of noise created by the speaker.
One technique to perform a straightforward check of the noise performance of a pair of cordless speakers is to short circuit the transmitter audio input and then to crank up the cordless speaker to its maximum. Next listen to the loudspeaker. Typically you will hear 2 components. The first is hissing. In addition, you will regularly hear a hum at 50 or 60 Hz. Both of these are components which are produced by the cordless loudspeaker itself. Next compare several sets of cordless loudspeakers according to the following rule: the smaller the amount of hiss, the better the noise performance of the cordless loudspeaker. On the other hand, keep in mind that you must set all sets of wireless speakers to amplify by the same amount to compare several models.
To help you evaluate the noise performance, cordless speaker suppliers publish the signal-to-noise ratio in their cordless speaker spec sheets. Simply put, the higher the signal-to-noise ratio, the lower the level of noise the wireless speaker creates. One of the reasons why cordless loudspeakers produce noise is the fact that they use elements such as transistors as well as resistors which by nature produce noise. The overall noise is dependent on how much noise each component generates. Yet, the location of these elements is also vital. Components which are part of the loudspeaker built-in amp input stage are going to usually contribute most of the noise.
One more cause of hiss is the cordless music broadcast itself. Usually models that utilize FM type transmission at 900 MHz will have a fairly large amount of noise. The amount of static is also dependent upon the level of wireless interference from other transmitters. Newer models will usually utilize digital music broadcast 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 as well as the resolution of the cordless protocol.
A lot of of today's cordless speaker use amplifiers which are based on a digital switching topology. These amplifiers are named "class-D" or "class-T" amplifiers. Switching amplifiers include a power stage that is constantly switched at a frequency of around 400 kHz. As a result, the output signal of wireless speaker switching amps exhibit a moderately big amount of switching noise. This noise component, though, is usually inaudible because it is well above 20 kHz. On the other hand, it may still contribute to speaker distortion. Signal-to-noise ratio is usually only shown within the range of 20 Hz to 20 kHz. For that reason, a lowpass filter is used when measuring wireless speaker amps to remove the switching noise.
The most popular technique for measuring the signal-to-noise ratio is to couple the wireless speaker to a gain which allows the maximum output swing. Then a test signal is input into the transmitter. The frequency of this signal is typically 1 kHz. The amplitude of this signal is 60 dB below the full scale signal. Then, only the hiss between 20 Hz and 20 kHz is considered. The noise at different frequencies is removed by a filter. Next the amount of the noise energy in relation to the full-scale output power is computed and shown in decibel.
Time and again the signal-to-noise ratio is shown in a more subjective method as "dbA" or "A weighted". This method was developed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most responsive to signals around 1 kHz. However, signals under 50 Hz and above 13 kHz are barely noticed. An A-weighted signal-to-noise ratio weighs the noise floor according to the human hearing and is usually larger than the unweighted signal-to-noise ratio.
