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.
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.
Lately a lot of people have got a smartphone. The majority of the latest generation cell phones may keep tunes in addition to video clips. Many people utilize ear buds to enjoy the tunes stored on their cellular phones. Often those earbuds will be packaged along with your phone. Though these kinds of ear buds happen to be compact and handy to carry, almost all of these ear buds have pretty poor audio quality, regrettably. But, you can actually get significantly better sound quality by simply transmitting the music to a set of stereo speakers. Should you be looking for a method to send tracks from your cellphone to some stereo speakers then you can find quite a few alternate options to choose from. In this article I’ll evaluate a number of of those choices to be able to offer you a better idea about what is out there.
Most stereo speakers possess significantly better sound quality when compared with mini headphones and thus are generally a better option for enjoying music from your cellular phone. There are quite a few possible choices for transmitting your tracks to the speakers. I will be mainly looking at wireless solutions because you are not looking for your smartphone to be tethered to your stereo speakers. One of the most common possibilities designed for transmitting audio to a pair of speakers are Bluetooth A2DP receivers. Most of these receivers may acquire the cordless signal from a cellular phone and also recover the music. Bluetooth works with quite a few protocols intended for streaming songs. A2DP and AptX happen to be some of the most popular standards. AptX, though, is just understood by the newest generation of cell phones whilst A2DP is supported by virtually all mobile handsets.
An important deliberation over making use of Bluetooth audio receivers is the fact that they can only be connected to active loudspeakers. As an alternative you can make use of a power amplifier. Integrated Bluetooth cordless amps, on the other hand, do not need a separate audio amp. However, the wireless range of Bluetooth is fairly limited. Usually you are not able to transmit for more than 30 feet. This means you are limited to one room. Apart from mobile devices, a lot of other devices understand Bluetooth and can also transmit to these kinds of music receivers.
Airplay is able to offer improved audio quality in comparison with Bluetooth considering that it can transmit uncompressed music. However, most of the time the tunes saved on your phone is compressed in a way. Most people store MP3 compressed audio. If that’s so Airplay won’t improve the sound quality over Bluetooth. AptX is a rather recent protocol for the purpose of transmitting tracks within Bluetooth. A large number of older mobile phones, however, usually do not yet understand AptX.
Another option for streaming tunes from a cellular phone are Bluetooth cordless loudspeakers. Bluetooth loudspeakers are normally fairly small. Therefore, these typically lack when it comes to audio quality. Try out any product before you buy any kind of Bluetooth stereo speakers in order to prevent an upsetting surprise. Additionally you really should make sure that any specific model of Bluetooth wireless stereo speakers is compatible with your smartphone before your purchase.
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.
Are you attempting to set up a new home theater system or some speakers? The easiest way is to hire a competent installer to aid you. On the other hand, you might consider doing the setup yourself. I will outline the basic setup procedure and present some tricks to help stay away from some widespread problems.
Your home theater system will normally include 5 or 7 loudspeakers – one main loudspeaker, two front speakers, two rears as well as two sides (in case of a 7.1 system) in addition to a subwoofer. It also comes with a main element. This element will drive all of your speakers. This central component is also referred to as surround sound receiver or amplifier. It is the main hub of your home theater system. Make certain that you put this receiver in a location which is fairly centrally positioned in order to minimize the amount of speaker wire which you need to run. You don’t inevitably need to place the receiver right next to your TV. Just make sure it is in a dry and safe place. In addition, be sure that you can easily reach the receiver from your television set or DVD/Blue-ray player because you will need to connect those. Attaching the receiver to power and to your television set or Blue-ray player is pretty easy. Most modern TVs include an optical output which connects straight to your receiver using a fiberoptical cord. This cable is generally included with your system. You may also get it a most electronics shops. After you have established the audio connection to your TV, you can now go ahead and connect your speakers. This step demands a little more effort.
Determine the length of loudspeaker wire that you are going to require for connecting all of the satellite loudspeakers. Ensure to add some extra cable to take into account those bends and corners. If you are planning to drive a lot of power to your speakers then be sure you select a cable that is thick enough to handle the current flow. Your woofer is going to usually have a built-in power amplifier and attach to your receiver via RCA cable. The loudspeaker cord connects to every speaker by the speaker terminals. These terminals are color coded. This helps observe the right polarity while connecting the loudspeaker cord. Most loudspeaker cable will show one strand in a different color. This is essential since it is going to help guarantee the right polarity of the loudspeaker terminal connection. Just connect the different-color strand to the speaker terminal which is colored. Then, whilst attaching the speaker cord to your receiver, make sure that you connect the cord to each loudspeaker terminal at the receiver in the identical manner. This will keep the sound going to each speaker in the right phase and optimize your sound experience. Wireless speakers usually need to employ some amount of audio buffering during the transmission to cope with wireless interference. This results in a brief delay while the audio is broadcast. This delay is also known as latency and should be taken into consideration during your set up. Ideally, all loudspeakers have the same latency and as a result are in perfect sync. If you have both wireless as well as wired loudspeakers, the wireless speakers will be out of sync with the wired speakers. Thus you will have to delay the audio going to the wired speakers by tweaking your receiver. The amount of delay should be identical to the latency of the cordless loudspeakers. Confirm with the manufacturer if your surround receiver can be set to delay the audio of particular channels. If you are using wireless rears, you want to set the front-speaker and side-speaker channels to delay the signal. Home theater systems that were not designed for wireless rear speakers might not have this ability. In this case you may wish to look for a wireless speaker kit which has very low latency, ideally less than one ms. This is going to keep all of your speakers (Read this regarding outdoor stereo speakers) in perfect sync. Uncover further materials at http://www.sonos.com/.
An ever expanding number of cordless gadgets including wireless speakers is causing increasing competition for the valuable frequency space. I’ll examine a number of technologies which are used by the latest digital sound gadgets to discover how well these products can operate in a real-world situation.
The buzz of cordless devices such as wireless outdoor speakers is mainly responsible for a quick rise of transmitters which transmit in the preferred frequency bands of 900 MHz, 2.4 GHz and 5.8 GHz and therefore cordless interference has turned into a major problem. FM type audio transmitters are generally the least reliable in regards to tolerating interference because the transmission does not have any method to deal with competing transmitters. On the other hand, those transmitters use a fairly limited bandwidth and changing channels can frequently steer clear of interference. Modern sound gadgets employ digital sound transmission and frequently operate at 2.4 GHz. Those digital transmitters transmit a signal that takes up more frequency space than 900 MHz transmitters and thus have a greater possibility of colliding with other transmitters. Just switching channels, on the other hand, is no reliable remedy for avoiding specific transmitters that use frequency hopping. Frequency hoppers such as Bluetooth products or many cordless telephones are going to hop throughout the full frequency spectrum. Hence transmission on channels is going to be disrupted for short bursts of time. Audio can be regarded as a real-time protocol. Consequently it has strict needs regarding stability. Furthermore, low latency is essential in most applications. Thus more advanced techniques are required to ensure dependability. A frequently utilized technique is forward error correction where the transmitter transmits supplemental information along with the audio. Because of this additional information, the receiver can easily restore the original data whether or not the signal was damaged to a certain degree. FEC is unidirectional. The receiver does not send back any information to the transmitter. Thus it is often used by equipment similar to radio receivers in which the quantity of receivers is big.
A different approach makes use of bidirectional transmission, i.e. every receiver transmits information back to the transmitter. This strategy is only helpful if the quantity of receivers is small. Additionally, it needs a back channel to the transmitter. The information packets have a checksum from which every receiver can determine whether a packet was received properly and acknowledge proper receipt to the transmitter. In situations of dropped packets, the receiver is going to notify the transmitter and the dropped packet is resent. Therefore both the transmitter and also receiver have to have a buffer to keep packets. This will create an audio latency, also called delay, to the transmission which is often a challenge for real-time protocols like audio. Generally, the bigger the buffer is, the greater the robustness of the transmission. However a large buffer can result in a large latency which may bring about issues with loudspeakers not being synchronized with the video. One constraint is that products where the receiver communicates with the transmitter can usually only broadcast to a small number of cordless receivers. Also, receivers have to incorporate a transmitter and usually consume additional current
Often a frequency channel can get occupied by a different transmitter. Ideally the transmitter is going to realize this fact and change to yet another channel. To do so, a few wireless speakers consistently monitor which channels are available so that they can quickly switch to a clean channel. Considering that the transmitter has a list of clean channels, there is no delay in trying to find a clear channel. It is simply selected from the list. This strategy is usually called adaptive frequency hopping spread spectrum.
None of modern stereo systems would be doable lacking the aid of today’s mini audio amps which strive to satisfy higher and higher demands concerning power and music fidelity. It is tough to select an amp given the big range of models and concepts. I am going to explain some of the most common amplifier designs including “tube amplifiers”, “linear amplifiers”, “class-AB” and “class-D” as well as “class-T amplifiers” to help you comprehend some of the terms normally utilized by amplifier makers. This essay should also help you figure out what topology is best for your precise application.
Simply put, the principle of an audio amp is to convert a low-power music signal into a high-power audio signal. The high-power signal is big enough to drive a loudspeaker sufficiently loud. The type of element used to amplify the signal depends on what amp topology is utilized. Some amplifiers even make use of several types of elements. Generally the following parts are utilized: tubes, bipolar transistors and FETs. A couple of decades ago, the most widespread kind of audio amplifier were tube amps. Tube amps utilize a tube as the amplifying element. The current flow through the tube is controlled by a low-level control signal. Thereby the low-level audio is converted into a high-level signal. Tubes, though, are nonlinear in their behavior and will introduce a rather large level of higher harmonics or distortion. Today, tube amps still have many followers. The main reason is that the distortion that tubes bring about are frequently perceived as “warm” or “pleasant”. Solid state amplifiers with low distortion, on the other hand, are perceived as “cold”.
A disadvantage of tube amps is their low power efficiency. In other words, most of the power consumed by the amp is wasted as heat instead of being transformed into audio. Therefore tube amplifiers are going to run hot and require enough cooling. Tube amplifiers, however, a fairly costly to manufacture and as a result tube amplifiers have mostly been replaced with amplifiers utilizing transistor elements which are less expensive to build.
The first generation types of solid state amplifiers are often known as “Class-A” amps. Solid-state amplifiers employ a semiconductor rather than a tube to amplify the signal. Regularly bipolar transistors or FETs are being used. The working principle of class-A amps is quite similar to that of tube amps. The main difference is that a transistor is being used as opposed to the tube for amplifying the music signal. The amplified high-level signal is sometimes fed back in order to minimize harmonic distortion. In terms of harmonic distortion, class-A amps rank highest amid all types of music amplifiers. These amps also typically exhibit quite low noise. As such class-A amps are perfect for quite demanding applications in which low distortion and low noise are essential. Yet, similar to tube amps, class-A amps have extremely low power efficiency and the majority of the energy is wasted. Class-AB amplifiers improve on the efficiency of class-A amps. They utilize a number of transistors in order to split up the large-level signals into two separate regions, each of which can be amplified more efficiently. Because of the larger efficiency, class-AB amps do not need the same number of heat sinks as class-A amps. Therefore they can be made lighter and less costly. Nonetheless, this topology adds some non-linearity or distortion in the region where the signal switches between those regions. As such class-AB amps typically have larger distortion than class-A amplifiers.
To further improve the audio efficiency, “class-D” amps employ a switching stage that is continually switched between 2 states: on or off. None of these 2 states dissipates energy within the transistor. Therefore, class-D amps regularly are able to achieve power efficiencies beyond 90%. The switching transistor, that is being controlled by a pulse-width modulator generates a high-frequency switching component which has to be removed from the amplified signal by utilizing a lowpass filter. The switching transistor and in addition the pulse-width modulator frequently exhibit fairly big non-linearities. As a consequence, the amplified signal will have some distortion. Class-D amplifiers by nature have higher audio distortion than other types of audio amplifiers. To solve the dilemma of large music distortion, modern switching amplifier designs incorporate feedback. The amplified signal is compared with the original low-level signal and errors are corrected. One type of audio amplifiers which makes use of this type of feedback is called “class-T” or “t amplifier”. Class-T amps feed back the high-level switching signal to the audio signal processor for comparison. These amplifiers have small music distortion and can be manufactured extremely small.