To help you select a couple of cordless loudspeakers, I will clarify the expression "signal-to-noise ratio" which is frequently utilized to explain the performance of wireless speakers.
As soon as you have narrowed down your search by looking at a few key criteria, like the level of output wattage, the dimensions of the loudspeakers as well as the price, you will still have quite a few products to choose from. Now it is time to look at some of the technical specs in more detail. An important criterion of wireless loudspeakers 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 music signal. This ratio is usually described in decibel or "db" for short.
A way to accomplish a simple check of the noise performance of a set of cordless speakers is to short circuit the transmitter audio input and then to crank up the wireless loudspeaker to its maximum. After that listen to the loudspeaker. You will hear some amount of hissing and/or hum coming from the loudspeaker. This hiss is created by the wireless loudspeaker itself. Make certain that the volume of each pair of cordless loudspeakers is set to the same amount. Otherwise you will not be able to objectively compare the level of static between several models. The general rule is: the lower the level of static that you hear the better the noise performance.
Whilst glancing at the cordless loudspeaker specification sheet, you want to look for a pair of wireless loudspeaker with a large signal-to-noise ratio figure which indicates that the wireless speakers output a small amount of hiss. One of the reasons why cordless loudspeakers generate noise is the fact that they use elements like transistors and resistors which by nature produce noise. Because the built-in power amp overall noise performance is mostly determined by the performance of components situated at the amplifier input, producers will try to pick low-noise parts while developing the amp input stage of their wireless speakers.
The wireless transmission itself also will cause noise which is most noticable with models which utilize FM transmission at 900 MHz. Other cordless transmitters will interfer with FM type transmitters and result in further static. Therefore the signal-to-noise ratio of FM type wireless 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, modern transmitters use digital music broadcast and generally transmit at 2.4 GHz or 5.8 GHz. This kind of music broadcast provides larger signal-to-noise ratio than analog type transmitters. The amount of noise depends on the resolution of the analog-to-digital converters along with the quality of other components.
Most of today's wireless loudspeaker use amplifiers which are based on a digital switching topology. These amplifiers are called "class-D" or "class-T" amplifiers. Switching amplifiers include 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. On the other hand, modern wireless speakerspecifications normally only consider the hiss between 20 Hz and 20 kHz.
The signal-to-noise ratio is measured by feeding a 1 kHz test signal 60 dB below the full scale and measuring the noise floor of the signal generated by the built-in amp. The gain of the cordless loudspeaker is set such that the full output wattage of the built-in amp can be achieved. Subsequently, the noise floor between 20 Hz and 20 kHz is measured and the ratio to the full-scale signal calculated. The noise signal at different frequencies is removed via a bandpass filter throughout this measurement.
Another convention in order to express the signal-to-noise ratio utilizes more subjective terms. These terms are "dBA" or "A weighted". You will find these terms in most cordless loudspeaker spec sheets. In other words, this method tries to state how the noise is perceived by a person. Human hearing is most sensitive to signals around 1 kHz whereas signals under 50 Hz and above 14 kHz are hardly heard. The A-weighted signal-to-noise ratio is frequently larger than the unweighted ratio and is published in most wireless loudspeaker parameter sheets.
As soon as you have narrowed down your search by looking at a few key criteria, like the level of output wattage, the dimensions of the loudspeakers as well as the price, you will still have quite a few products to choose from. Now it is time to look at some of the technical specs in more detail. An important criterion of wireless loudspeakers 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 music signal. This ratio is usually described in decibel or "db" for short.
A way to accomplish a simple check of the noise performance of a set of cordless speakers is to short circuit the transmitter audio input and then to crank up the wireless loudspeaker to its maximum. After that listen to the loudspeaker. You will hear some amount of hissing and/or hum coming from the loudspeaker. This hiss is created by the wireless loudspeaker itself. Make certain that the volume of each pair of cordless loudspeakers is set to the same amount. Otherwise you will not be able to objectively compare the level of static between several models. The general rule is: the lower the level of static that you hear the better the noise performance.
Whilst glancing at the cordless loudspeaker specification sheet, you want to look for a pair of wireless loudspeaker with a large signal-to-noise ratio figure which indicates that the wireless speakers output a small amount of hiss. One of the reasons why cordless loudspeakers generate noise is the fact that they use elements like transistors and resistors which by nature produce noise. Because the built-in power amp overall noise performance is mostly determined by the performance of components situated at the amplifier input, producers will try to pick low-noise parts while developing the amp input stage of their wireless speakers.
The wireless transmission itself also will cause noise which is most noticable with models which utilize FM transmission at 900 MHz. Other cordless transmitters will interfer with FM type transmitters and result in further static. Therefore the signal-to-noise ratio of FM type wireless 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, modern transmitters use digital music broadcast and generally transmit at 2.4 GHz or 5.8 GHz. This kind of music broadcast provides larger signal-to-noise ratio than analog type transmitters. The amount of noise depends on the resolution of the analog-to-digital converters along with the quality of other components.
Most of today's wireless loudspeaker use amplifiers which are based on a digital switching topology. These amplifiers are called "class-D" or "class-T" amplifiers. Switching amplifiers include 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. On the other hand, modern wireless speakerspecifications normally only consider the hiss between 20 Hz and 20 kHz.
The signal-to-noise ratio is measured by feeding a 1 kHz test signal 60 dB below the full scale and measuring the noise floor of the signal generated by the built-in amp. The gain of the cordless loudspeaker is set such that the full output wattage of the built-in amp can be achieved. Subsequently, the noise floor between 20 Hz and 20 kHz is measured and the ratio to the full-scale signal calculated. The noise signal at different frequencies is removed via a bandpass filter throughout this measurement.
Another convention in order to express the signal-to-noise ratio utilizes more subjective terms. These terms are "dBA" or "A weighted". You will find these terms in most cordless loudspeaker spec sheets. In other words, this method tries to state how the noise is perceived by a person. Human hearing is most sensitive to signals around 1 kHz whereas signals under 50 Hz and above 14 kHz are hardly heard. The A-weighted signal-to-noise ratio is frequently larger than the unweighted ratio and is published in most wireless loudspeaker parameter sheets.
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