Some Technical Guidelines For Purchasing A Pair Of Cordless Speakers
Are you looking to get a new a set of wireless speakers for your home? You might be dazzled by the number of alternatives you have. In order to make an informed choice, it is best to familiarize yourself with common specs. One of these terms is named “signal-to-noise ratio” and is not often understood. I will help explain the meaning of this term.
While trying to find a couple of cordless speakers, you first are going to check the cost, wattage amid other essential criteria. Nonetheless, after this initial selection, you are going to still have several types to choose from. Next you are going to concentrate more on several of the technical specifications, like signal-to-noise ratio in addition to harmonic distortion. One important parameter of cordless speakers is the signal-to-noise ratio. To put it simply, the signal-to-noise ratio describes how much hum or hiss the speakers will add to the music signal. This ratio is usually described in decibel or “db” for short.
Comparing the noise level of different sets of cordless loudspeakers may be done quite easily. Simply gather a couple of versions which you want to evaluate and short circuit the transmitter audio inputs. Then put the wireless speaker volume to maximum and verify the level of static by listening to the loudspeaker. By and large you will hear two components. The first is hissing. In addition, you are going to regularly hear a hum at 50 or 60 Hz. Both of these are components which are produced by the wireless speaker itself.
To help you compare the noise performance, wireless loudspeaker manufacturers publish the signal-to-noise ratio in their wireless loudspeaker spec sheets. Simply put, the higher the signal-to-noise ratio, the lower the level of noise the cordless speaker generates. Noise is produced due to several factors. One reason is that modern wireless speakers all employ elements such as transistors plus resistors. Those components are going to create some amount of noise. Since the built-in power amplifier overall noise performance is mostly determined by the performance of components situated at the amp input, makers are going to try to pick low-noise elements whilst developing the amp input stage of their wireless loudspeakers.
Static is also brought on by the cordless broadcast. Different styles of transmitters are available which work at different frequencies. The cheapest kind of transmitters employs FM transmission and commonly broadcasts at 900 MHz. FM transmitters are very prone to cordless interference which is why newer types usually utilize digital audio transmission. The signal-to-noise ratio of digital transmitters is independent from the distance of the cordless loudspeakers. 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 modern wireless speakers have built-in power amps that include a power switching stage which switches at a frequency around 500 kHz. Because of this, the output signal of wireless speaker switching amps contain a rather large level of switching noise. This noise component, however, is usually impossible to hear because it is well above 20 kHz. Though, it can still contribute to speaker distortion. Signal-to-noise ratio is normally only shown within the range of 20 Hz to 20 kHz. For that reason, a lowpass filter is utilized when measuring cordless loudspeaker amps in order to remove the switching noise.
The signal-to-noise ratio is measured by feeding a 1 kHz test tone 60 dB underneath the full scale and measuring the noise floor of the signal generated by the built-in amp. The gain of the cordless speaker is set such that the full output wattage of the built-in amp can be achieved. After that the noise-floor energy is calculated in the frequency range between 20 Hz and 20 kHz and compared with the full scale signal energy.
Frequently you will discover the term “dBA” or “a-weighted” in your wireless loudspeaker spec sheet. A weighting is a method of expressing the noise floor in a more subjective fashion. This method was developed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most sensitive to signals around 1 kHz. On the other hand, signals below 50 Hz and above 13 kHz are barely heard. The A-weighted signal-to-noise ratio is typically higher than the unweighted ratio and is published in the majority of wireless loudspeaker parameter sheets.