Can Rock Outdoor Speakers Produce CD-Quality Audio?

Have you ever asked what some of the technical language means that vendors use in order to show the performance of wireless loudspeakers? In this editorial, I will highlight a frequently used specification: THD or “total harmonic distortion”.

wireless speakers

Wireless loudspeakers are available in all different shapes and sizes. Selecting the right model may often be tough. I am going to shed some light on a commonly utilized term that is utilized in order to publish the technical performance of the speaker: “total harmonic distortion” or “THD”. THD is usually not as easily understood as a few other commonly utilized specs including “signal-to-noise ratio” or “frequency response”.

In brief, THD shows the difference between the audio that is produced by the speaker versus the audio signal with which the speaker is driven. The most widespread ways to show distortion are percent in addition to decibel. These two conventions can be translated into one another. The percentage given as THD shows which amount of energy which is radiated by the speaker are higher harmonics versus the original signal. 10% would mean that one 10th is distortion. 1% would mean one hundredth et cetera. 10% is equal to -20 dB while 1% equals -40 dB. On the other hand, be cautious as there are in fact several elements which bring about harmonic distortion. Wireless loudspeakers as well as any kind of active loudspeaker or active subwoofer all have built-in power amplifiers in order to drive the speaker element. The power amplifier itself is going to have a specific amount of distortion. Generally the distortion of the amp will be bigger the more output power it supplies to the loudspeaker. Customarily vendors will specify amplifier distortion based on a specific amount of power, by and large a lot less than the rated highest amplifier output power.

Having amp distortion specs for a few output power levels provides a better picture of the amplifier distortion performance.Harmonic distortion measurements are typically done via feeding a test tone into the speaker. This signal is a pure sine wave signal with minimum distortion. The frequency of this test tone is normally 1 kHz. Distortion, though, is usually dependent on the audio frequency. Most amplifiers will show rising distortion with rising frequency. Particularly digital class-D amplifiers will show fairly high distortion at frequencies above 5 kHz.

The second contributing factor is the loudspeaker element itself. The majority of speakers employ a diaphragm kind driver which is driven by a coil that is suspended in a magnetic field. The voicecoil will follow the magnetic field that is controlled by the music signal in order to move the diaphragm. Yet, this movement is not completely linear. As such the result is distortion caused by the speaker element. Most vendors will exhibit harmonic distortion depending on the audio level as typically the higher the speaker is driven the bigger the amount of distortion.

The total distortion of the speaker thus is the sum of the amp distortion as well as the loudspeaker element distortion. On top of that, there are different contributing factors. The enclosure of the speaker will vibrate to some extent depending on the sound pressure level. These vibrations are going to also be non-linear in nature and add to distortion.

In order to figure out the overall distortion of a loudspeaker, a signal generator is utilized which supplies an ultra-linear signal to the speaker and a measurement microphone which is attached to an audio analyzer in order to calculate the level of harmonics emitted by the loudspeaker. Then again, pure sine signals barely give an accurate indication of the distortion of the cordless loudspeaker with real-world signals. A better distortion analysis is the so-called intermodulation distortion analysis where a test tone which includes a number of sine waves is used. Then the number of harmonics at other frequencies is calculated.

Furthermore, please understand that most wireless speakers introduced at this link will experience audio distortion during the audio transmission itself. This is mostly the case for transmitters which utilize analog or FM type transmission. Digital audio transmission on the other hand provides the smallest level of signal distortion. The audio is digitized in the transmitter and not affected during the transmission itself. Digital wireless audio transmitters are available at 2.4 GHz as well as 5.8 GHz.


Why It Is Good To Choose A Couple Of Efficient Cordless Loudspeakers

When you are about to buy brand new wireless speakers, you may well be asking yourself how efficiently your wireless loudspeakers operate. I’m going to explain exactly what the term “power efficiency” stands for plus why you must take a closer look at this figure in your selection of brand new cordless loudspeakers. The less efficient your wireless loudspeakers are, the more energy is going to be squandered which results in many difficulties: Low-efficiency wireless loudspeakers will waste some power as heat and so are costlier to use than high-efficiency products because of their greater energy utilization. To shield the circuit elements, low-efficiency wireless loudspeakers must find methods to remove the heat that’s produced. Generally more elements have to be added to dissipate enough energy and sustain the ideal operating temperature. These components usually are heat sinks and also fans. These heat sinks consume a reasonable amount of room and make the wireless speakers large and heavy. Further more, they raise the price of the wireless loudspeakers. Cordless speakers that have low efficiency can’t be put in small spaces or within sealed enclosures as they need a good amount of circulation. Cordless loudspeakers that have small efficiency have to have a bigger power source to output the same level of music power as high-efficiency versions. Further, because of the large amount of heat, there will be much greater thermal stress on the electrical elements as well as internal materials which may result in dependability problems. In comparison, high-efficiency wireless loudspeakers can be produced small and lightweight.

The efficiency is shown as a percentage in the outdoor wireless speakers data sheet. Analog Class-D amplifiers offer a power efficiency of roughly 25% whilst switching-mode amps offer close to 98%. The larger the efficiency figure, the less the amount of energy wasted as heat. A 100-Watt amplifier having 50% efficiency would have a power consumption of 200 W.

Please note, however, that efficiency is dependent upon just how much energy the amp provides at a given moment. Amplifiers possess greater efficiency when delivering higher output power than when working at low power due to the fixed energy that they use up irrespective of the output power. The efficiency value in the amp data sheet is usually provided for the greatest amp output power.

The measurement setup of amp power efficiency utilizes a power resistor that is attached to the amp. The amplifier itself is being fed a constant-envelope sine-wave tone. Then the power consumed by the resistor is tested and divided by the power the amp consumes. Normally a complete power report is plotted to show the dependency of the efficiency on the output power. For this reason the output power is swept through various values. The efficiency at every value is tested and a efficiency plot generated.

Even though switching (Class-D) amplifiers have amongst the greatest efficiency, they have a tendency to have larger music distortion than analog music amps and reduced signal-to-noise ratio. As a result you will have to weigh the dimensions of the wireless speakers against the audio fidelity. Some new wireless loudspeakers, including models which include Class-T amps, are able to lessen audio distortion to amounts near to the ones from types using analog music amplifiers and in addition can accomplish great signal-to-noise ratio. Selecting one of these cordless speakers will deliver high power efficiency and at the same time large music fidelity.