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ヘッドフォン Amphony H2000のPDF よくある質問をオンラインで閲覧またはダウンロードできます。Amphony H2000 5 ページ。 2.4 ghz digital wireless headphones
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Q: How does the transmitter connect to my audio equipment ?

A: The transmitter connects to any standard analog audio line output via the supplied stereo RCA

audio cable and to coaxial and optical digital audio outputs. In cases where no analog line output

(RCA audio out) is available, the transmitter can also connect to other audio outputs via appropriate

adapters which are not supplied with the product. By using a Y adapter which has either a 3.5 mm

or a 6.3 mm audio plug on one side and 2 RCA plugs on the other side, the transmitter can be

connected to headphone outputs.

Q: Can the transmitter connect to the digital audio output of my audio equipment ?

A: Yes, in addition to the analog audio interface, the Model 2000 transmitter features a coaxial and

an optical digital audio interface. By using one of these interfaces, the transmitter can be connected

to any standard digital audio output. The transmitter will format the digital audio data and send it to

the headphones without making any changes to the audio data or sample rate and without applying

any audio compression. Therefore, the audio data received by the headphones is exactly the same

as the data which is received at the digital input. The digital inputs of the transmitter bypass the

integrated analog-to-digital converter and eliminate any unnecessary analog-to-digital or digital-to-

analog conversion. Since no noise or audio degradation is introduced by the digital audio interface,

the signal-to-noise ratio is highest when using a digital audio interface. Please note that the digital

audio interfaces only process uncompressed linear audio data at the sample rates of

32 kHz, 44.1 kHz or 48 kHz. They do not process compressed multichannel audio data. In such a

case, an external surround decoder is necessary or the analog audio interface can be used.

Q: What does the noise shaping filter of the Model 2000 headphones do ?

A: Digital audio, such as audio on a CD and the audio transmitted to the headphones, is

represented by numbers that represent voltage levels. When analog audio is converted to digital

audio, the voltage of the audio signal is sampled and represented by a number that refers to the

voltage that comes closest to the actual voltage. Because there is usually a small difference

between that voltage and the actual voltage of the analog audio signal, a certain amount of noise -

quantization noise - is introduced. The amount of such quantization noise is, among other things,

determined by the amount of information that is used to represent each sample - resolution.

Therefore, digital audio on a CD and audio transmitted to the headphones always contains a small

amount of quantization noise which limits the maximum possible signal-to-noise ratio of the

transmission. In order to increase the signal-to-noise ration beyond that limit, the Model 2000

headphones feature a special noise shaping filter which is a 5th-order filter that outputs the audio at

64 times the sampling frequency and shifts the audio data quantization noise to higher frequencies

that are outside of the audible frequency band. As a result, the Model 2000 is able to achieve a

higher signal-to-noise ratio than would be possible without a noise shaping filter.

Q: What is Forward Error Correction and why is it used in these headphones ?

A: Occasionally, there may be some data which is corrupted during transmission. This may be the

case when there is interference, such as other transmitters, electrical sparks or if you move around

and the signal is temporarily lost. Forward Error Correction as it is used in our headphones can in

most cases repair the data which is received to guarantee 100% correct data reception and

therefore 100% correct audio reception.