To help you decide on a couple of cordless speakers, I am going to describe the expression "signal-to-noise ratio" which is regularly used to describe the performance of wireless loudspeakers.
After you have narrowed down your search by taking a look at several fundamental criteria, such as the amount of output wattage, the size of the loudspeakers plus the cost, you will still have quite a few models to choose from. Now it is time to take a look at a couple of the technical specs in more detail. An important parameter of wireless speakers is the signal-to-noise ratio. To put it simply, the signal-to-noise ratio shows how much hum or hiss the speakers will add to the music signal. This ratio is customarily shown in decibel or "db" for short.
You can perform a simple comparison of the cordless loudspeaker hiss by short circuiting the transmitter input, setting the loudspeaker volume to maximum and listening to the speaker. You are going to hear some amount of hissing and/or hum coming from the speaker. This hiss is created by the cordless speaker itself. Ensure that the gain of each couple of cordless loudspeakers is set to the same amount. Otherwise you will not be able to objectively compare the amount of hiss between different models. The general rule is: the smaller the level of static which you hear the better the noise performance.
If you prefer a pair of cordless loudspeakers with a small level of hissing, you may look at the signal-to-noise ratio number of the specification sheet. Most producers are going to show this figure. wireless loudspeakers with a large signal-to-noise ratio will output a small amount of noise. One of the reasons why cordless speakers generate noise is the fact that they utilize elements including transistors and resistors that by nature produce noise. Since the built-in power amplifier overall noise performance is mostly determined by the performance of components situated at the amp input, producers are going to try to pick low-noise parts when developing the amplifier input stage of their cordless loudspeakers.
The wireless transmission itself also creates noise which is most noticable with products that employ FM transmission at 900 MHz. Other cordless transmitters will interfer with FM type transmitters and create further noise. Consequently the signal-to-noise ratio of FM type wireless loudspeakers varies depending on the distance of the speakers from the transmitter and the amount of interference. To avoid these problems, newer transmitters employ digital music transmission and usually transmit at 2.4 GHz or 5.8 GHz. This kind of audio transmission offers better signal-to-noise ratio than analog type transmitters. The level of hiss is dependent on the resolution of the analog-to-digital converters along with the quality of other components.
A lot of of latest cordless speaker use amps which are based on a digital switching architecture. These amplifiers are called "class-D" or "class-T" amps. Switching amplifiers incorporate a power stage that is always switched at a frequency of approximately 400 kHz. This switching frequency is also noise which is part of the amplified signal. Yet, today's wireless speakerspecs usually 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 tone 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 between 20 Hz and 20 kHz is calculated and the ratio to the full-scale signal computed. The noise signal at different frequencies is removed by a bandpass filter throughout this measurement.
Frequently you will discover the expression "dBA" or "a-weighted" in your wireless loudspeaker parameter sheet. A weighting is a method of expressing the noise floor in a more subjective manner. This technique tries to examine in how far the cordless speaker noise is perceived by human hearing which is most sensitive to signals at frequencies at 1 kHz. Thus an A-weighting filter is going to magnify the noise floor for frequencies that are easily perceived and suppress the noise floor at frequencies which are barely perceived. A lot of cordless speaker will show a higher A-weighted signal-to-noise ratio than the un-weighted ratio.
After you have narrowed down your search by taking a look at several fundamental criteria, such as the amount of output wattage, the size of the loudspeakers plus the cost, you will still have quite a few models to choose from. Now it is time to take a look at a couple of the technical specs in more detail. An important parameter of wireless speakers is the signal-to-noise ratio. To put it simply, the signal-to-noise ratio shows how much hum or hiss the speakers will add to the music signal. This ratio is customarily shown in decibel or "db" for short.
You can perform a simple comparison of the cordless loudspeaker hiss by short circuiting the transmitter input, setting the loudspeaker volume to maximum and listening to the speaker. You are going to hear some amount of hissing and/or hum coming from the speaker. This hiss is created by the cordless speaker itself. Ensure that the gain of each couple of cordless loudspeakers is set to the same amount. Otherwise you will not be able to objectively compare the amount of hiss between different models. The general rule is: the smaller the level of static which you hear the better the noise performance.
If you prefer a pair of cordless loudspeakers with a small level of hissing, you may look at the signal-to-noise ratio number of the specification sheet. Most producers are going to show this figure. wireless loudspeakers with a large signal-to-noise ratio will output a small amount of noise. One of the reasons why cordless speakers generate noise is the fact that they utilize elements including transistors and resistors that by nature produce noise. Since the built-in power amplifier overall noise performance is mostly determined by the performance of components situated at the amp input, producers are going to try to pick low-noise parts when developing the amplifier input stage of their cordless loudspeakers.
The wireless transmission itself also creates noise which is most noticable with products that employ FM transmission at 900 MHz. Other cordless transmitters will interfer with FM type transmitters and create further noise. Consequently the signal-to-noise ratio of FM type wireless loudspeakers varies depending on the distance of the speakers from the transmitter and the amount of interference. To avoid these problems, newer transmitters employ digital music transmission and usually transmit at 2.4 GHz or 5.8 GHz. This kind of audio transmission offers better signal-to-noise ratio than analog type transmitters. The level of hiss is dependent on the resolution of the analog-to-digital converters along with the quality of other components.
A lot of of latest cordless speaker use amps which are based on a digital switching architecture. These amplifiers are called "class-D" or "class-T" amps. Switching amplifiers incorporate a power stage that is always switched at a frequency of approximately 400 kHz. This switching frequency is also noise which is part of the amplified signal. Yet, today's wireless speakerspecs usually 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 tone 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 between 20 Hz and 20 kHz is calculated and the ratio to the full-scale signal computed. The noise signal at different frequencies is removed by a bandpass filter throughout this measurement.
Frequently you will discover the expression "dBA" or "a-weighted" in your wireless loudspeaker parameter sheet. A weighting is a method of expressing the noise floor in a more subjective manner. This technique tries to examine in how far the cordless speaker noise is perceived by human hearing which is most sensitive to signals at frequencies at 1 kHz. Thus an A-weighting filter is going to magnify the noise floor for frequencies that are easily perceived and suppress the noise floor at frequencies which are barely perceived. A lot of cordless speaker will show a higher A-weighted signal-to-noise ratio than the un-weighted ratio.
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