Some Technical Pointers For Purchasing A Set Of Wireless Loudspeakers

By Author: Lisa Frickle
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Are you looking to buy a brand new a pair of high-tech iPod speaker models for your home? You might be dazzled by the amount of options you have. In order to make an informed selection, it is best to familiarize yourself with common specs. One of these terms is called "signal-to-noise ratio" and is not often understood. I will help explain the meaning of this expression.Once you have narrowed down your search by taking a look at a few basic criteria, including the level of output wattage, the size of the speakers plus the cost, you are going to still have quite a few products to choose from. Now it is time to take a look at a few of the technical specifications in more detail. Each wireless speaker is going to produce a certain amount of hiss as well as hum. The signal-to-noise ratio will help quantify the amount of hiss produced by the speaker. Comparing the noise level of several sets of cordless speakers can be done rather simply. Simply get together a few versions that you wish to evaluate and short circuit the transmitter audio inputs. Afterward put the ...
... wireless speaker gain to maximum and verify the level of hiss by listening to the speaker. The noise that you hear is generated by the wireless loudspeaker itself. Make sure that the volume of each couple of wireless speakers is set to the same level. Otherwise you will not be able to objectively compare the amount of static between different models. The general rule is: the smaller the amount of noise that you hear the higher the noise performance.When taking a look at the cordless speaker spec sheet, you want to look for a set of wireless speaker with a high signal-to-noise ratio number which suggests that the cordless loudspeakers output a small amount of static. One of the reasons why cordless loudspeakers create noise is the fact that they utilize components including transistors as well as resistors which by nature create noise. The overall noise depends on how much hiss each component generates. Yet, the location of these elements is also essential. Components which are part of the speaker built-in amp input stage will usually contribute most of the noise.One more cause of static is the wireless audio broadcast itself. Generally products that utilize FM style transmission at 900 MHz will have a comparatively high level of hiss. The level of hiss is also dependent upon the level of wireless interference from other transmitters. Modern types are going to generally make use of digital music broadcast at 2.4 GHz or 5.8 GHz. The signal-to-noise ratio of digital transmitters is independent from the distance of the cordless speakers. It is determined by how the music signal is sampled. In addition, the quality of components inside the transmitter are going to influence the signal-to-noise ratio.A lot of today's cordless loudspeakers have built-in power amplifiers that include a wattage switching stage which switches at a frequency around 500 kHz. Consequently, the output signal of wireless loudspeaker switching amps have a rather big amount of switching noise. This noise component, though, is usually inaudible since it is well above 20 kHz. Yet, it can still contribute to speaker distortion. Signal-to-noise ratio is typically only shown within the range of 20 Hz to 20 kHz. Thus, a lowpass filter is used when measuring cordless loudspeaker amplifiers in order to remove the switching noise.The signal-to-noise ratio is measured by inputting a 1 kHz test tone 60 dB below the full scale and measuring the noise floor of the signal generated by the built-in amp. The volume of the wireless loudspeaker is set such that the full output power of the built-in amp can be realized. Next, 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 eliminated through a bandpass filter during this measurement.Frequently you are going to discover the expression "dBA" or "a-weighted" in your cordless speaker specification sheet. A weighting is a technique of showing the noise floor in a more subjective manner. This method was designed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most perceptive to signals around 1 kHz. Then again, signals under 50 Hz and above 13 kHz are hardly heard. An A-weighted signal-to-noise ratio weighs the noise floor in accordance to the human hearing and is typically higher than the unweighted signal-to-noise ratio.