Tag Archives: outdoor loudspeakers

How Much Static Do Portable Wireless Speakers Create?

To help you pick a set of cordless speakers, I will clarify the term “signal-to-noise ratio” which is commonly used in order to describe the performance of wireless loudspeakers. Once you have chosen a number of wireless loudspeakers, it’s time to explore some of the specs in more detail to help you narrow down your search to one product. The signal-to-noise ratio is a rather key parameter and describes how much noise or hiss the wireless loudspeaker makes. Comparing the noise level of several sets of wireless loudspeakers can be done quite easily. Just gather a number of products that you wish to evaluate and short circuit the transmitter audio inputs. Afterward set the wireless speaker gain to maximum and check the level of noise by listening to the loudspeaker. The noise that you hear is generated by the wireless speaker itself. After that compare different sets of cordless loudspeakers according to the following rule: the lower the amount of noise, the better the noise performance of the cordless speaker. Though, bear in mind that you must put all sets of cordless loudspeakers to amplify by the same level to evaluate different models.

wireless speakers

If you prefer a set of cordless speakers with a small amount of hissing, you can look at the signal-to-noise ratio number of the specification sheet. A lot of manufacturers will display this figure. wireless loudspeakers with a high signal-to-noise ratio will output a low amount of hiss. One of the reasons why wireless outdoor speakers sold by Amphony Inc. create noise is the fact that they utilize components including transistors as well as resistors which by nature produce noise. The overall noise depends on how much noise each component generates. Yet, the location of those elements is also essential. Elements which are part of the loudspeaker built-in amplifier input stage will normally contribute the majority of the noise. Static is also brought on by the wireless transmission. Different kinds of transmitters are available which operate at different frequencies. The cheapest sort of transmitters utilizes FM transmission and usually broadcasts at 900 MHz. The level of hiss is also dependent upon the level of cordless interference from other transmitters. Newer models are going to usually employ digital audio transmission at 2.4 GHz or 5.8 GHz. The signal-to-noise ratio of digital transmitters is dependent mostly on the kind of analog-to-digital converters and other components that are utilized as well as the resolution of the cordless protocol. Most today’s cordless loudspeakers have built-in power amps that incorporate a power switching stage which switches at a frequency around 500 kHz. As a result, the output signal of wireless speaker switching amps contain a fairly big level of switching noise. This noise component, however, is generally impossible to hear given that it is well above 20 kHz. Nonetheless, it can still contribute to loudspeaker distortion. Signal-to-noise ratio is generally only shown within the range of 20 Hz to 20 kHz. Thus, a lowpass filter is used when measuring wireless loudspeaker amps to eliminate the switching noise. Manufacturers measure the signal-to-noise ratio by setting the built-in amplifier such that the full output swing can be realized and by feeding a test tone to the transmitter which is usually 60 dB underneath the full scale of the speaker amp. Next, only the hiss 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 computed and shown in decibel. A different convention in order to state the signal-to-noise ratio makes use of more subjective terms. These terms are “dBA” or “A weighted”. You are going to find these terms in many wireless loudspeaker parameter sheets. In other words, this method tries to state how the noise is perceived by a person. Human hearing is most perceptive to signals around 1 kHz while signals below 50 Hz and above 14 kHz are hardly heard. The A-weighted signal-to-noise ratio is frequently higher than the unweighted ratio and is published in most wireless loudspeaker parameter sheets.


Points To Realize About Cordless Loudspeaker Power Efficiency

Current wireless speakers will naturally squander some amount of power they use up. Picking pair of cordless speakers with high power efficiency can lower the amount of squandered power. I will talk about some little-known facts about power efficiency that will help you select the ideal product.

A fairly high amount of energy is radiated as heat when you get a pair of low-efficiency wireless loudspeakers. This can produce quite a few issues: Cordless loudspeakers that have low power efficiency are going to squander a great amount of energy. It’s smart to keep in mind the additional power cost while choosing between a high- and low-efficiency model. The wasted energy is radiated by the bluetooth speakers as heat. To safeguard the circuit elements, low-efficiency cordless loudspeakers must find ways to get rid of the heat that’s created. Commonly additional components must be included to dissipate adequate power and preserve the optimum running temperature. These components usually are heat sinks along with fans. These heat sinks use up a good amount of space and make the cordless speakers large and heavy. Additionally, they add to the cost of the cordless loudspeakers. Low-efficiency cordless speakers further need a great deal of circulation around the cordless speakers. Therefore they can not be placed in close spaces or inside air-tight enclosures.

Low-efficiency products require more total power in order to output the identical level of audio power as high-efficiency models. As a result they require a larger power source which makes the wireless speakers more expensive to make. Further, due to the large level of heat, there will be considerably higher thermal stress on the electric elements and internal materials which may cause reliability complications. In comparison, high-efficiency wireless speakers can be made small and light.

While looking for a pair of wireless speakers, you can find the efficiency in the data sheet. This figure is usually shown as a percentage. Class-A amplifiers are among the least efficient and provide a power efficiency of approximately 25% only. In contrast, switching amps, often known as “Class-D” amps deliver efficiencies as high as 98%. The larger the efficiency figure, the less the amount of energy squandered as heat. A 100-Watt amp which has a 50% efficiency will have an energy usage of 200 Watts. What’s less known about efficiency is the fact that this figure isn’t fixed. The truth is it fluctuates depending on how much energy the amp offers. Therefore at times you will discover efficiency values for several power levels in the data sheet. Amps have larger efficiency while supplying greater output power than when working at small power because of the fixed power that they use up irrespective of the output power. The efficiency value in the amp data sheet is typically provided for the greatest amplifier output power.

The measurement setup of amp power efficiency uses a power resistor that is attached to the amplifier. The amp itself is being fed a constant-envelope sine-wave tone. Next the energy absorbed by the resistor is tested and divided by the energy the amp consumes. To obtain a complete efficiency profile, the audio power of the amplifier is swept between several values. At each value the efficiency is tested and then plotted onto a graph.

While switching (Class-D) amps possess amongst the greatest efficiency, they have a tendency to possess larger sound distortion than analog music amplifiers and smaller signal-to-noise ratio. As a result you are going to have to weigh the size of the cordless loudspeakers against the sound fidelity. Then again, digital amps have come a long way and are offering improved music fidelity than ever before. Wireless speakers which employ Class-T amps come close to the music fidelity of products which have analog amplifiers. Due to this fact selecting a set of wireless loudspeakers which employ switching amplifier with good audio fidelity is now feasible.