By Linda Cullmann
To help you choose a couple of cordless loudspeakers, I am going to clarify the expression "signal-to-noise ratio" which is usually utilized to express the performance of wireless speakers.
As soon as you have narrowed down your search by taking a look at some key criteria, such as the amount of output power, the dimensions of the speakers in addition to the price, you will still have quite a few models to choose from. Now it is time to take a look at some of the technical specifications in more detail. One important criterion of wireless loudspeakers is the signal-to-noise ratio. To put it simply, the signal-to-noise ratio describes how much hum or hiss the loudspeakers are going to add to the audio signal. This ratio is generally shown in decibel or "db" for short.
As soon as you have narrowed down your search by taking a look at some key criteria, such as the amount of output power, the dimensions of the speakers in addition to the price, you will still have quite a few models to choose from. Now it is time to take a look at some of the technical specifications in more detail. One important criterion of wireless loudspeakers is the signal-to-noise ratio. To put it simply, the signal-to-noise ratio describes how much hum or hiss the loudspeakers are going to add to the audio signal. This ratio is generally shown in decibel or "db" for short.
A method in order to accomplish a simple assessment of the noise performance of a set of cordless loudspeakers is to short circuit the transmitter audio input and then to crank up the cordless speaker to its utmost. Subsequently listen to the speaker. You will hear some amount of hissing and/or hum coming from the speaker. This hiss is generated by the wireless speaker itself. Next compare different sets of wireless loudspeakers according to the next rule: the lower the amount of noise, the higher the noise performance of the cordless speaker. However, bear in mind that you must put all sets of wireless loudspeakers to amplify by the same amount in order to compare several models.
If you favor a set of cordless speakers with a small level of hissing, you may look at the signal-to-noise ratio figure of the specification sheet. Many producers will show this figure. cordless speakers with a high signal-to-noise ratio are going to output a small level of noise. One of the reasons why cordless speakers produce noise is the fact that they use elements like transistors and resistors that by nature generate noise. Since the built-in power amp overall noise performance is mostly determined by the performance of components located at the amplifier input, producers are going to attempt to choose low-noise components whilst developing the amplifier input stage of their cordless loudspeakers.
The cordless broadcast itself also causes noise which is most noticable with types which use FM transmission at 900 MHz. The level of static is also dependent upon the level of cordless interference from other transmitters. Newer types will normally employ digital audio broadcast at 2.4 GHz or 5.8 GHz. The signal-to-noise ratio of digital transmitters is dependent mostly on the type of analog-to-digital converters and other components that are used as well as the resolution of the wireless protocol.
The majority of modern wireless speakers use power amplifiers which are digital, also called "class-d amplifiers". Class-D amplifiers make use of a switching stage which oscillates at a frequency between 300 kHz to 1 MHz. This switching noise can cause some amount of loudspeaker distortion yet is generally not included in the signal-to-noise ratio which only considers noise between 20 Hz and 20 kHz.
If you favor a set of cordless speakers with a small level of hissing, you may look at the signal-to-noise ratio figure of the specification sheet. Many producers will show this figure. cordless speakers with a high signal-to-noise ratio are going to output a small level of noise. One of the reasons why cordless speakers produce noise is the fact that they use elements like transistors and resistors that by nature generate noise. Since the built-in power amp overall noise performance is mostly determined by the performance of components located at the amplifier input, producers are going to attempt to choose low-noise components whilst developing the amplifier input stage of their cordless loudspeakers.
The cordless broadcast itself also causes noise which is most noticable with types which use FM transmission at 900 MHz. The level of static is also dependent upon the level of cordless interference from other transmitters. Newer types will normally employ digital audio broadcast at 2.4 GHz or 5.8 GHz. The signal-to-noise ratio of digital transmitters is dependent mostly on the type of analog-to-digital converters and other components that are used as well as the resolution of the wireless protocol.
The majority of modern wireless speakers use power amplifiers which are digital, also called "class-d amplifiers". Class-D amplifiers make use of a switching stage which oscillates at a frequency between 300 kHz to 1 MHz. This switching noise can cause some amount of loudspeaker distortion yet is generally not included in the signal-to-noise ratio which only considers noise between 20 Hz and 20 kHz.
The cordless broadcast itself also causes noise which is most noticable with types which use FM transmission at 900 MHz. The level of static is also dependent upon the level of cordless interference from other transmitters. Newer types will normally employ digital audio broadcast at 2.4 GHz or 5.8 GHz. The signal-to-noise ratio of digital transmitters is dependent mostly on the type of analog-to-digital converters and other components that are used as well as the resolution of the wireless protocol.
The majority of modern wireless speakers use power amplifiers which are digital, also called "class-d amplifiers". Class-D amplifiers make use of a switching stage which oscillates at a frequency between 300 kHz to 1 MHz. This switching noise can cause some amount of loudspeaker distortion yet is generally not included in the signal-to-noise ratio which only considers noise between 20 Hz and 20 kHz.
The signal-to-noise ratio is measured by feeding a 1 kHz test tone 60 dB below the full scale and measuring the noise floor of the signal generated by the built-in amplifier. The gain of the cordless speaker is set such that the full output wattage of the built-in amp can be realized. Next, only the noise between 20 Hz and 20 kHz is considered. The noise at different frequencies is removed by a filter. Then the amount of the noise energy in relation to the full-scale output power is calculated and expressed in db.
Time and again the signal-to-noise ratio is shown in a more subjective way as "dbA" or "A weighted". In other words, this method attempts to express how the noise is perceived by a person. Human hearing is most perceptive to signals around 1 kHz whereas signals under 50 Hz and above 14 kHz are hardly noticed. The A-weighted signal-to-noise ratio is typically higher than the unweighted ratio and is published in most cordless speaker parameter sheets.
The majority of modern wireless speakers use power amplifiers which are digital, also called "class-d amplifiers". Class-D amplifiers make use of a switching stage which oscillates at a frequency between 300 kHz to 1 MHz. This switching noise can cause some amount of loudspeaker distortion yet is generally not included in the signal-to-noise ratio which only considers noise between 20 Hz and 20 kHz.
The signal-to-noise ratio is measured by feeding a 1 kHz test tone 60 dB below the full scale and measuring the noise floor of the signal generated by the built-in amplifier. The gain of the cordless speaker is set such that the full output wattage of the built-in amp can be realized. Next, only the noise between 20 Hz and 20 kHz is considered. The noise at different frequencies is removed by a filter. Then the amount of the noise energy in relation to the full-scale output power is calculated and expressed in db.
Time and again the signal-to-noise ratio is shown in a more subjective way as "dbA" or "A weighted". In other words, this method attempts to express how the noise is perceived by a person. Human hearing is most perceptive to signals around 1 kHz whereas signals under 50 Hz and above 14 kHz are hardly noticed. The A-weighted signal-to-noise ratio is typically higher than the unweighted ratio and is published in most cordless speaker parameter sheets.