It is easy to be bewildered by the language which cordless loudspeaker suppliers utilize in order to describe the performance of their products. I am going to clarify the meaning of a usually used specification: "signal-to-noise ratio" in order to help you make an informed decision when buying a brand new a set of wireless loudspeakers.
As soon as you have chosen a number of wireless loudspeakers, it's time to explore a few of the specs in more detail in order to help you narrow down your search to one product. The signal-to-noise ratio is a rather vital parameter and describes how much noise or hiss the cordless loudspeaker produces.
You can make a simple assessment of the wireless loudspeaker hiss by short circuiting the transmitter input, setting the loudspeaker volume to maximum and listening to the loudspeaker. Typically you will hear two 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 speaker itself. Next compare different sets of cordless loudspeakers according to the next rule: the smaller the amount of noise, the higher the noise performance of the cordless loudspeaker. Though, bear in mind that you should put all sets of cordless speakers to amplify by the same level in order to compare several models.
While taking a look at the wireless speaker specification sheet, you want to look for a set of wireless speaker with a high signal-to-noise ratio number which indicates that the cordless loudspeakers output a small level of hiss. One of the reasons why cordless loudspeakers create noise is the fact that they utilize components including transistors as well as resistors that by nature generate noise. Since the built-in power amplifier overall noise performance is mostly determined by the performance of components located at the amplifier input, producers are going to attempt to pick low-noise elements whilst designing the amp input stage of their wireless loudspeakers.
The cordless broadcast itself also will cause static which is most noticable with models which employ FM transmission at 900 MHz. The level of hiss is also dependent upon the amount of wireless interference from other transmitters. Modern models will usually utilize digital audio broadcast at 2.4 GHz or 5.8 GHz. The signal-to-noise ratio of digital transmitters depends mostly on the type of analog-to-digital converters and other parts which are used along with the resolution of the cordless protocol.
A lot of of modern cordless speaker use amps which are based on a digital switching topology. These amplifiers are named "class-D" or "class-T" amplifiers. Switching amplifiers include a power stage which is constantly switched at a frequency of around 400 kHz. This switching frequency is also noise which is part of the amplified signal. However, modern cordless speakerspecifications generally only consider the noise between 20 Hz and 20 kHz.
Manufacturers measure the signal-to-noise ratio by setting the built-in amp such that the full output swing may be achieved and by inputting a test signal to the transmitter which is normally 60 dB below the full scale of the loudspeaker amplifier. After that 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 shown in a more subjective manner as "dbA" or "A weighted". This technique was developed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most responsive to signals around 1 kHz. On the other hand, signals under 50 Hz and higher than 13 kHz are hardly heard. Therefore an A-weighting filter will magnify the noise floor for frequencies which are easily heard and suppress the noise floor at frequencies that are barely noticed. The majority of wireless speaker are going to have a larger A-weighted signal-to-noise ratio than the un-weighted ratio.
As soon as you have chosen a number of wireless loudspeakers, it's time to explore a few of the specs in more detail in order to help you narrow down your search to one product. The signal-to-noise ratio is a rather vital parameter and describes how much noise or hiss the cordless loudspeaker produces.
You can make a simple assessment of the wireless loudspeaker hiss by short circuiting the transmitter input, setting the loudspeaker volume to maximum and listening to the loudspeaker. Typically you will hear two 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 speaker itself. Next compare different sets of cordless loudspeakers according to the next rule: the smaller the amount of noise, the higher the noise performance of the cordless loudspeaker. Though, bear in mind that you should put all sets of cordless speakers to amplify by the same level in order to compare several models.
While taking a look at the wireless speaker specification sheet, you want to look for a set of wireless speaker with a high signal-to-noise ratio number which indicates that the cordless loudspeakers output a small level of hiss. One of the reasons why cordless loudspeakers create noise is the fact that they utilize components including transistors as well as resistors that by nature generate noise. Since the built-in power amplifier overall noise performance is mostly determined by the performance of components located at the amplifier input, producers are going to attempt to pick low-noise elements whilst designing the amp input stage of their wireless loudspeakers.
The cordless broadcast itself also will cause static which is most noticable with models which employ FM transmission at 900 MHz. The level of hiss is also dependent upon the amount of wireless interference from other transmitters. Modern models will usually utilize digital audio broadcast at 2.4 GHz or 5.8 GHz. The signal-to-noise ratio of digital transmitters depends mostly on the type of analog-to-digital converters and other parts which are used along with the resolution of the cordless protocol.
A lot of of modern cordless speaker use amps which are based on a digital switching topology. These amplifiers are named "class-D" or "class-T" amplifiers. Switching amplifiers include a power stage which is constantly switched at a frequency of around 400 kHz. This switching frequency is also noise which is part of the amplified signal. However, modern cordless speakerspecifications generally only consider the noise between 20 Hz and 20 kHz.
Manufacturers measure the signal-to-noise ratio by setting the built-in amp such that the full output swing may be achieved and by inputting a test signal to the transmitter which is normally 60 dB below the full scale of the loudspeaker amplifier. After that 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 shown in a more subjective manner as "dbA" or "A weighted". This technique was developed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most responsive to signals around 1 kHz. On the other hand, signals under 50 Hz and higher than 13 kHz are hardly heard. Therefore an A-weighting filter will magnify the noise floor for frequencies which are easily heard and suppress the noise floor at frequencies that are barely noticed. The majority of wireless speaker are going to have a larger A-weighted signal-to-noise ratio than the un-weighted ratio.
No comments:
Post a Comment