Several Practical Advice For Finding A Set Of Cordless Speakers

It is easy to be baffled by the language which wireless speaker makers use in order to depict the performance of their products. I am going to explain the meaning of a commonly used specification: "signal-to-noise ratio" to help you make an informed choice when buying a brand new a couple of cordless loudspeakers.

Once you have narrowed down your search by taking a look at some basic criteria, like the amount of output power, the dimensions of the speakers plus 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. Each cordless speaker will create a certain level of hiss and hum. The signal-to-noise ratio is going to help compute the amount of noise generated by the speaker.

Comparing the noise level of different sets of wireless loudspeakers may be accomplished fairly easily. Simply gather several types which you want to compare and short circuit the transmitter audio inputs. After that put the wireless speaker gain to maximum and check the level of noise by listening to the loudspeaker. Typically you are going to 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 generated by the cordless loudspeaker itself. Make certain that the gain of each pair of cordless speakers is set to the same amount. Otherwise you will not be able to objectively evaluate the level of static between different models. The general rule is: the lower the level of hiss which you hear the higher the noise performance.

If you favor a set of cordless loudspeakers with a small amount of hissing, you can look at the signal-to-noise ratio figure of the specification sheet. A lot of manufacturers will show this figure. wireless speakers with a large signal-to-noise ratio will output a low amount of static. There are several reasons why wireless loudspeakers are going to add some form of noise or other unwanted signal. Transistors and resistors which are part of every modern wireless speaker by nature make noise. Because the built-in power amp overall noise performance is mostly determined by the performance of elements located at the amp input, producers will attempt to select low-noise parts when developing the amp input stage of their wireless loudspeakers.

The cordless transmission itself also causes hiss that is most noticable with products that utilize FM transmission at 900 MHz. FM transmitters are very prone to wireless interference which is why newer models usually employ digital audio broadcast. This style of audio transmission provides larger signal-to-noise ratio than analog style transmitters. The level of noise depends on the resolution of the analog-to-digital converters in addition to the quality of other components.

Most of today’s cordless loudspeakers use power amplifiers which are digital, also known as "class-d amps". Class-D amplifiers make use of a switching stage that oscillates at a frequency in the range of 300 kHz to 1 MHz. In consequence, the output signal of wireless speaker switching amps contain a moderately big amount of switching noise. This noise component, though, is typically impossible to hear because it is well above 20 kHz. Yet, it can still contribute to loudspeaker 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 while measuring wireless loudspeaker amps in order to eliminate the switching noise.

The signal-to-noise ratio is measured by inputting a 1 kHz test tone 60 dB underneath the full scale and measuring the noise floor of the signal generated by the built-in amplifier. The amplification of the cordless loudspeaker is set such that the full output power of the built-in amplifier can be realized. Subsequently, only the hiss in the range of 20 Hz and 20 kHz is considered. The noise at other frequencies is removed via a filter. Subsequently the amount of the noise energy in relation to the full-scale output wattage is computed and expressed in db.

Frequently you are going to find the term "dBA" or "a-weighted" in your wireless speaker spec sheet. A weighting is a technique of expressing the noise floor in a more subjective manner. This technique was developed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most sensitive to signals around 1 kHz. However, signals below 50 Hz and higher than 13 kHz are hardly noticed. The A-weighted signal-to-noise ratio is generally higher than the unweighted ratio and is published in the majority of wireless loudspeaker parameter sheets.