Explaining The Total Harmonic Distortion Spec Of Outdoor Wireless Stereo Speakers

Have you ever asked what some of the technical language means that suppliers take to spell out the quality of wireless loudspeakers? In this essay, I will clarify one regularly used spec: THD or “total harmonic distortion”.

wireless speakers

It is often tricky to select a suitable set of wireless speakers made by Amphony Inc. given the huge number of products. Aside from looks, you will often be faced with having to examine several of the technical specs. THD is generally not as easily understood as some other commonly utilized specs including “signal-to-noise ratio” or “frequency response”.

wireless speakers

THD is expressed either in percent or in decibel and indicates how much the signal which the loudspeaker outputs deviates from the audio signal which is fed into the speaker. The percentage shown as THD shows which amount of energy which is radiated by the loudspeaker are higher harmonics versus the original signal. 10% would mean that one 10th is distortion. 1% would mean one 100th and so forth. 10% equals -20 dB whilst 1% equals -40 dB.

Though, be cautious since there are actually several elements which cause harmonic distortion. Wireless loudspeakers as well as any sort of active speaker or active subwoofer all have built-in power amplifiers to drive the speaker element. The audio amplifier itself will have a certain level of distortion. Usually the distortion of the amp will be larger the more output power it supplies to the loudspeaker. Normally manufacturers are going to publish amplifier distortion based on a specific amount of power, generally a lot less than the rated highest amplifier output power. Distortion specifications for various output power levels are usually shown for several power levels or as a chart showing distortion versus output power. Both of these methods allow to better evaluate the quality of the amplifier.Harmonic distortion measurements are typically conducted by feeding a test signal into the loudspeaker. This tone is a pure sine wave signal with minimum distortion. The frequency of this test tone is usually 1 kHz. Still, amplifier distortion will generally increase with rising frequency, especially in digital class-D products. One more component causing distortion is the speaker element that usually works with a diaphragm that carries a coil which is suspended in a magnetic field. The magnetic field is excited by the music signal. The change in magnetic flux, however, is not completely in sync with the music signal as a result of core losses as well as other factors. In addition, the kind of suspension of the diaphragm will cause nonlinear movement. This results in the signal being distorted by the loudspeaker element itself. What’s more, the bigger to power level with which the loudspeaker is driven, the larger the distortion. Often speaker vendors are going to display distortion for small to moderate output power levels only.

The overall distortion of the speaker thus is the sum total of the amplifier distortion as well as the speaker element distortion. Furthermore, there are other contributing factors. Depending on the material used to manufacture the loudspeaker enclosure, there will be vibrations or enclosure resonances. Those normally depend on the sound pressure level, the enclosure shape, the enclosure material along with audio frequency. Consequently extra audio distortion will be brought on by the box itself.

Total distortion is best determined through measurement. A signal generator is used which provides a highly linear sine tone to the loudspeaker. The audio is picked up by a measurement microphone. The microphone signal is then analyzed by an audio analyzer. The audio analyzer is going to compute the level of higher harmonics or distortion. Another distortion measurement method that offers a better analysis of the speaker performance with real-world signals is called interharmonic distortion analysis. This method outputs two signals at different frequencies and measures the level of harmonics at other frequencies.

wireless speakers

Also, please understand that many wireless speakers are going to experience signal distortion during the audio transmission itself. This is mostly the case for transmitters which use analog or FM type transmission. More advanced products employ digital audio transmission. Usually these transmitters work at 2.4 GHz or 5.8 GHz.


Information On Picking Out Good-Quality Cordless Loudspeakers

To help you select a couple of cordless speakers, I am going to clarify the expression “signal-to-noise ratio” that is usually utilized to depict the performance of wireless speakers. Once you have chosen a range of wireless speakers, it is time to investigate a few of the specs in more detail to help you narrow down your search to one model. The signal-to-noise ratio is a fairly vital spec and explains how much noise or hiss the cordless speaker makes. A way to perform a simple test of the noise performance of a set of wireless loudspeakers is to short circuit the transmitter audio input and then to crank up the cordless loudspeaker to its utmost. After that listen to the speaker. You are going to hear some amount of hissing and/or hum coming from the loudspeaker. This hiss is produced by the cordless speaker itself. Then compare several sets of cordless loudspeakers according to the next rule: the smaller the amount of noise, the higher the noise performance of the cordless speaker. On the other hand, bear in mind that you have to set all sets of wireless speakers to amplify by the same amount in order to evaluate different models.

When looking at the wireless loudspeaker spec sheet, you want to look for a set of wireless loudspeaker with a high signal-to-noise ratio figure which indicates that the cordless loudspeakers output a low amount of hiss. Noise is generated due to several reasons. One reason is that today’s cordless loudspeakers all employ elements such as transistors as well as resistors. These components will generate some amount of hiss. The overall noise is dependent on how much hiss each element produces. Yet, the location of those components is also important. Components that are part of the loudspeaker built-in amp input stage will usually contribute the majority of the noise. An additional cause of noise is the wireless audio transmission itself. Usually types which make use of FM type broadcast at 900 MHz are going to have a rather large level of hiss. Other cordless transmitters are going to interfer with FM type transmitters and bring about further static. As a result the signal-to-noise ratio of FM type cordless loudspeakers (Read this article about wireless speakers) varies depending on the distance of the loudspeakers from the transmitter plus the amount of interference. To steer clear of these problems, newer transmitters make use of digital audio broadcast and usually broadcast at 2.4 GHz or 5.8 GHz. This kind of audio transmission offers larger signal-to-noise ratio than analog type transmitters. The level of noise is dependent on the resolution of the analog-to-digital converters and the quality of other parts. Many of recent wireless loudspeaker use amplifiers which are based on a digital switching architecture. These amplifiers are referred to as “class-D” or “class-T” amps. Switching amps incorporate a power stage that is continuously switched at a frequency of around 400 kHz. This switching noise may result in some level of speaker distortion but is typically not included in the signal-to-noise ratio which only considers noise in the range of 20 Hz and 20 kHz.

The signal-to-noise ratio is measured by feeding 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 gain of the wireless speaker is pair such that the full output wattage of the built-in amp can be achieved. After that, only the hiss between 20 Hz and 20 kHz is considered. The noise at different frequencies is eliminated through a filter. Subsequently the level of the noise energy in relation to the full-scale output power is computed and shown in decibel. Frequently you will discover the term “dBA” or “a-weighted” in your wireless loudspeaker specification sheet. A weighting is a method of expressing the noise floor in a more subjective way. This technique was designed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most responsive to signals around 1 kHz. Then again, signals below 50 Hz and above 13 kHz are hardly heard. Consequently an A-weighting filter is going to magnify the noise floor for frequencies which are easily heard and suppress the noise floor at frequencies which are hardly noticed. The majority of cordless speaker will have a larger A-weighted signal-to-noise ratio than the un-weighted ratio. In addition, check out http://www.dmzforum.org/zbxe/zbxe/?mid=DMZPublications&page=528&document_srl=516294 to get a lot more details.


Several Buying Recommendations For Bluetooth Music Receivers

Contemporary mobile devices enable you to store as well as watch movies and tunes. A lot of people make use of earphones to hear the tunes saved on their cell phones. Commonly such headphones will be offered along with your phone. While those ear buds usually are small plus convenient to carry, almost all of these types of earbuds have got rather poor audio quality, regrettably. Yet, it is easy to get much better audio quality through sending the audio to a set of loudspeakers. Attaching your stereo speakers to your phone by utilizing a cable is frequently not attractive. It’s easy to trip over the wire and the cell phone is connected to the stereo speakers. Below I’ll analyze various wireless options designed for streaming your songs to a pair of speakers. There are various choices in the marketplace intended for connecting loudspeakers to a cellphone. You can easily hook up your loudspeakers to the phone through wire or cordlessly. Cordless is a lot more hassle-free compared to employing a cable. Bluetooth speaker systems, for instance, allow sending of tunes by way of Bluetooth. These types of receivers may pick up the wireless signal from your cell phone and also retrieve the tracks. Most of the latest receivers understand the widespread standards A2DP and AptX. A2DP is certainly the most commonly used standard to send tunes by means of Bluetooth whilst AptX is just recognized by the most recent generation of smartphones.

Notice though that Bluetooth audio receivers are not able to connect to passive loudspeakers without using an audio amp. There are furthermore several integrated receivers/amplifiers out there. These types of types will not require an external power amp and are able to connect directly to any kind of passive stereo speakers. Bluetooth, however, provides a rather limited wireless range of about 30 ft and hence cannot be employed for the purpose of streaming music to different areas in your residence. The true range will depend on the surroundings and also on your smartphone. You can also send songs from many other gadgets that support Bluetooth by employing the same setup.

Airplay is able to offer greater audio quality in comparison with Bluetooth considering the fact that it may transmit uncompressed music. Then again, most of the time the tracks located on your cellphone is compressed in some fashion. Lots of people keep MP3 compressed songs. If that’s the case Airplay is not going to enhance the audio quality over Bluetooth. AptX is a relatively recent standard protocol designed for streaming songs via Bluetooth. It does offer close to CD-quality audio sending – again presuming that you have uncompressed music available. This specific protocol is not however recognized by a lot of mobile handsets but the latest Bluetooth receivers offer AptX as an option.

Bluetooth cordless loudspeakers tend to be a further option for the purpose of playing audio stored on your phone. There are actually plenty of models out there. Because Bluetooth stereo speakers often do not provide similar audio quality as other speakers, it’s usually advisable to give them a try just before your investment. Also you ought to be sure that any specific type of Bluetooth cordless loudspeakers works with your cellular phone just before your purchase.


Purchasing A Couple Of Efficient Cordless Loudspeakers

I’m going to look at the definition of “power efficiency” which tells you just how much cordless loudspeakers waste to guide you decide on a set of cordless loudspeakers.

A relatively large amount of energy is radiated as heat if you get a set of low-efficiency wireless loudspeakers. This can contribute to a few issues: Low-efficiency wireless loudspeakers are going to waste a certain amount of energy as heat and are more costly to use in comparison with high-efficiency models because of the higher power consumption. To protect the circuit elements, low-efficiency outdoor cordless loudspeakers need to find ways to get rid of the heat that’s generated. Commonly more elements have to be added to dissipate sufficient power and sustain the ideal working temperature. These components tend to be heat sinks along with fans. These heat sinks consume a reasonable amount of space and make the cordless speakers large and heavy. Additionally, they raise the expense of the wireless loudspeakers. Wireless speakers that have low efficiency can not be placed in small spaces or within sealed enclosures as they need a great deal of circulation.

Low-efficiency products require more total power in order to create the identical level of audio power as high-efficiency products. As a result they require a bigger power supply which makes the cordless loudspeakers more costly to construct. An elevated level of heat triggers extra stress on elements. The life expectancy of the cordless speakers might be reduced and reliability may be affected. High-efficiency cordless speakers on the other hand do not suffer from these problems and may be designed small.

The power efficiency is shown as a percentage in the wireless speakers data sheet. Analog Class-D amps provide a efficiency of roughly 25% while switching-mode amps provide up to 98%. From the efficiency percentage it is possible to figure out the amount of power the amp is going to waste. An amplifier with a 50% power efficiency is going to waste 50 % of the used power. An amp with 90% efficiency is going to waste 10%. Please be aware, though, that efficiency depends on just how much energy the amplifier delivers at a given moment. Amplifiers have larger efficiency while providing higher output power than while working at small power due to the fixed energy that they use up irrespective of the output power. The efficiency figure in the amp data sheet is normally provided for the maximum amp output power.

In order to determine the power efficiency, the audio power that is used by a power resistor that is attached to the amplifier is divided by the total energy the amplifier consumes whilst being fed a constant sine wave signal. To have a full power efficiency profile, the audio power of the amplifier is swept between different values. At every value the efficiency is measured and plotted onto a graph.

While switching (Class-D) amps possess amongst the highest efficiency, they tend to possess larger sound distortion than analog audio amps and reduced signal-to-noise ratio. For that reason you will have to weigh the dimensions of the cordless loudspeakers against the music fidelity. However, digital amplifiers have come a long way and are offering improved music fidelity than ever before. Cordless speakers which make use of Class-T amplifiers come close to the music fidelity of models which contain analog amplifiers. Due to this fact picking a set of cordless speakers which utilize switching amplifier with great music fidelity is now feasible.


A Short Introduction Of Power Amps

Stereo amps are at the very center of each home theater system. As the quality and output power demands of today’s speakers increase, so do the requirements of stereo amplifiers. There is a big amount of amplifier concepts and types. All of these differ in terms of performance. I am going to describe some of the most common amp terms like “class-A”, “class-D” and “t amps” to help you figure out which of these amps is ideal for your application. Also, after understanding this essay you should be able to comprehend the amp specifications which suppliers issue. Simply put, the principle of an audio amplifier is to convert a low-power audio signal into a high-power music signal. The high-power signal is big enough to drive a speaker adequately loud. Depending on the kind of amplifier, one of several types of elements are used in order to amplify the signal like tubes in addition to transistors.

A number of decades ago, the most widespread kind of audio amp were tube amplifiers. 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. One drawback with tubes is that they are not extremely linear when amplifying signals. Aside from the original audio, there will be overtones or higher harmonics present in the amplified signal. Hence tube amplifiers have moderately high distortion. Many people prefer tube amps since those higher harmonics are often perceived as the tube amp sounding “warm” or “pleasant”.

In addition, tube amplifiers have fairly low power efficiency and as a result radiate a lot of power as heat. Tube amplifiers, though, a quite costly to manufacture and as a result tube amplifiers have by and large been replaced with amplifiers utilizing transistor elements that are less expensive to build. Solid-state amps utilize a semiconductor element, like a bipolar transistor or FET instead of the tube and the earliest type is often known as “class-A” amps. In a class-A amp, the signal is being amplified by a transistor which is controlled by the low-level audio signal. If you need an ultra-low distortion amp then you might want to investigate class-A amps since they offer amongst the smallest distortion of any audio amplifiers. Class-A amps, however, waste the majority of the power as heat. Therefore they frequently have big heat sinks and are quite bulky.

By employing a number of transistors, class-AB amplifiers improve on the low power efficiency of class-A amps. The operating region is split into 2 separate areas. These 2 regions are handled by separate transistors. Each of these transistors works more efficiently than the single transistor in a class-A amp. As such, class-AB amps are generally smaller than class-A amps. When the signal transitions between the two distinct areas, though, a certain amount of distortion is being produced, thus class-AB amps will not achieve the same audio fidelity as class-A amps.

Class-D amps improve on the efficiency of class-AB amps even further by employing a switching transistor that is continuously being switched on or off. Thus this switching stage hardly dissipates any energy and therefore the power efficiency of class-D amps generally surpasses 90%. The switching transistor, which is being controlled by a pulse-width modulator generates a high-frequency switching component which has to be removed from the amplified signal by making use of a lowpass filter. Due to non-linearities of the pulse-width modulator and the switching transistor itself, class-D amps by nature have amongst the largest audio distortion of any audio amplifier.

To resolve the dilemma of high music distortion, modern switching amp styles incorporate feedback. The amplified signal is compared with the original low-level signal and errors are corrected. One kind of small stereo amps which utilizes this kind 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 amps exhibit small music distortion and can be manufactured very small.


The Best Way To Select The Most Dependable Wireless Speakers

I am going to examine just how present day sound transmission technologies which are employed in nowaday’s wireless speakers operate in real-world environments having a large amount of interference from other wireless gadgets.

The popularity of wireless gizmos just like wireless speakers is responsible for a quick increase of transmitters that transmit in the preferred frequency bands of 900 MHz, 2.4 Gigahertz as well as 5.8 Gigahertz and therefore cordless interference has become a serious problem.

FM type sound transmitters are generally the least reliable in terms of tolerating interference since the transmission does not have any procedure to deal with competing transmitters. Having said that, these types of transmitters have a relatively restricted bandwidth and changing channels may often eliminate interference. Advanced audio systems employ digital audio transmission and often work at 2.4 Gigahertz. These kinds of digital transmitters send out a signal that takes up a lot more frequency space than 900 MHz transmitters and thus have a greater potential for colliding with other transmitters. Simply switching channels, however, is no reliable remedy for steering clear of certain transmitters which use frequency hopping. Frequency hoppers which include Bluetooth gadgets as well as a lot of wireless phones are going to hop through the entire frequency spectrum. As a consequence transmission on channels is going to be disrupted for brief bursts of time. Audio can be regarded as a real-time protocol. Consequently it has strict requirements concerning reliability. In addition, small latency is vital in many applications. As a result more advanced methods are needed to assure dependability.

One of these strategies is referred to as forward error correction or FEC in short. The transmitter will broadcast additional information in addition to the audio data. Because of this added information, the receiver can easily recover the original data even when the signal was damaged to some extent. FEC is unidirectional. The receiver won’t send back any information to the transmitter. Thus it is often used by equipment including radio receivers in which the number of receivers is big.

In cases in which there is merely a small number of receivers, commonly yet another method is used. The wireless receiver sends information packets back to the transmitter to confirm proper receipt of data. The information which is transmit has a checksum. Using this checksum the receiver can see whether any particular packet was received correctly and acknowledge. If a packet was corrupted, the receiver will inform the transmitter and request retransmission of the packet. As a result, the transmitter needs to store a certain amount of packets in a buffer. Likewise, the receiver must maintain a data buffer. This buffer brings about an audio delay that depends on the buffer size with a larger buffer increasing the robustness of the transmission. A large latency can generate problems for several applications nonetheless. Particularly when video is present, the sound must be synchronized with the movie. Furthermore, in multichannel applications in which some loudspeakers are cordless, the wireless loudspeakers ought to be synchronized with the corded loudspeakers. One limitation is that systems in which the receiver communicates with the transmitter usually can only transmit to a few wireless receivers. Additionally, receivers must incorporate a transmitter and generally consume additional current So as to better cope with interference, several wireless speakers will monitor the available frequency band as a way to decide which channels are clear at any given point in time. If any specific channel becomes crowded by a competing transmitter, these devices may switch transmission to a clean channel without interruption of the audio. The clean channel is picked from a list of channels that was determined to be clear. One technology which employs this particular transmission protocol is called adaptive frequency hopping spread spectrum or AFHSS


The Best Secrets About Cell Phones Are Yours To Discover

Many people use cell phones as their only means of communication. Not only can they make phone calls, but you can also text, email and surf the Web. Keep reading and you’ll get great advice that can be used with the cell phone you have.

Be careful if you watch videos while using LTE or 4G. Most phone plans often come with a limited allowance for data each month. Video will take up a lot of your memory. If you’re going over your allowance often, you’re on the wrong plan.

Don’t think you have to rush to get a phone that’s updated. It may be a waste of money. Companies change what kinds of phones they have a lot, but they make minor updates sometimes. Read reviews prior to purchasing a new phone to see if you truly need to do it. It’s likely you don’t.

When purchasing a brand new cell phone, be sure to take time and do your research. Shopping in person, will allow you to hold multiple cell phones to see if they are comfortable to hold and to test out any unfamiliar new features they may have. By doing this, you will probably find the best phone for you, much easier.

Is your phone battery dying at speeds that seem way too fast? You might be experiencing a weak signal. Having a weak cell phone signal can actually drain your battery. When not using the phone, don’t put it somewhere that the signal is low.

The longer you own your smartphone, the more it will slow down. This means that it may become more difficult to perform updates to your phone as time passes. As a result, the time may come when you have to choose what you want to do. You can keep things the way they are, or decide to pursue an upgrade.

If you’ve got a newer phone, you may not need that expensive case to go with it. Designers of smartphones usually integrate a material that’s hard like Kevlar or carbon fiber in the frame during the manufacturing process. Cases can help boost their strength, but they can make using the phone harder. Know which choice is best for you, but make sure you base it off the type of cell phone you have.

You don’t need a smart phone if you only plan on using it to make phone calls. It seems like most people have smartphones these days, but it is usually because people use their phones to send emails or surf the Internet. They are usually more expensive than standard phones, so try saving money if you juts plan to talk on it.

A case isn’t needed for new phones (dig this to come across additional materials regarding cell phones for kids). A hard material such as Kevlar or a carbon fiber is typically used by smartphone designers when the phone is built. A case can add a layer of protection, but it can also be cumbersome. Find out about the construction of your phone before deciding whether or not you need a cover.

A case might not be necessary if you have one of the latest phones. Designers of smartphones are using Kevlar, carbon and other hard materials to make the phones stronger. A case will protect the glass, but can make the phone hard to use. Know which choice is best for you, but make sure you base it off the type of cell phone you have.

Playing mobile games can cure boredom and add some much needed excitement to your day. You’d be surprised at the quality of the games out there for cell phones. Don’t overburden your phone with too many games, since this can eat up your memory.

When you go shopping for a cell phone, don’t be overwhelmed by the number of options. While they seem like they vary wildly, there are some tips and advice that are pretty good ideas with most cell phones. This article has provided some valuable ideas to incorporate for use on your own phone.