Since electronic products entered the ranks of civil consumer products, earphones have become one of the most important electronic products of audio, video and entertainment. in especial mp3 ， mp4 The emergence of smart phones, tablets and other portable audio and video entertainment electronic products in recent years have made headphones more important. Thanks to the rapid development of digital signal processing and other technologies, the sound quality of earphones can also be improved, HiFi Professional audio processing technologies, such as, have also begun to be added to the production process of earphones. However, due to cost reasons, good audio quality earphones are generally priced high, ranging from thousands to tens of thousands, which is difficult for ordinary consumers to accept. This HD500 It is a pioneering work that has been meticulously produced for decades three hundred and forty-eight Of HiFi Can we balance the price and sound quality of earphones? Let's wait and see!

v Appearance

HD500 The outer package of is designed with a black cardboard box, which is high-end, grand, scientific, and strong. The front shows the basic features of this headset with the most concise elements

There are many words on the back. The model parameters and precautions of this headset were introduced in detail

It was very considerate to write down the precautions, which were also detailed in the instructions

Side of packing box

There are sealing labels on both sides, which can ensure that the user gets the original unopened product

OK After looking at the outer package, it's time to unpack, the product layout is reasonable, and the groove design is also very careful

Headphones and 3.5mm The audio cable is stored separately. The manufacturer carefully designed a layer of foam at the bottom of the cover box, It can effectively avoid scratching the headset

Pick up the foam frame for placing earphones and find a manual at the bottom of the box

HD500 There are two colors, titanium gray and brown, and the overall design of metal frame and leather

The two sound channels and the top of the frame are covered with leather jackets, which ensures that all parts in contact with the body are made of soft leather materials and will not cause discomfort

The two earphones are connected with the frame by a rotating shaft, which can rotate ninety °, easy to carry

The telescopic head beam design can adjust the radian of the wearer at will. In addition, the stainless steel material with excellent toughness can make the wearer fit the head more closely and greatly enhance the sound insulation effect

The headset and the head beam are fixed by four octagonal screws. All screw holes are polished smooth and the details are very good

To avoid wearing in the wrong direction, HD500 There are left and right channel marks on the inside of the head beam

3.5mm The audio interface is designed at the bottom of the right headset, and the interface edge has also been polished

The audio cable fitted to the headset is also full of components, much thicker than the ordinary audio cable

The plug adopts a three-stage gold-plated design, which can effectively reduce sound distortion

The overall design of this headworn wired headset is simple and elegant, and the details are perfect. If the appearance of the product is compared to an image, I will give HD500 hit ninety-eight . The reason for not giving full marks is that HD500 The weight is a little too heavy. I feel uncomfortable after wearing it for a long time. Personally, I think it can be improved.

v Sound quality

It seems that the image, then it's time to talk about temperament. Sound quality is one of the most important parameters to measure the quality of audio equipment HD500 The sound quality parameters of are: frequency response, total harmonic distortion THD ， 300Hz Square wave response and impulse response.

Test equipment includes: computer (including LabVIEW Signal acquisition and Artemis Analysis software), NI Acquisition module, test object HD500 Wired headphones, 1/4 Inch microphone

Frequency response is the most intuitive parameter reflecting the flatness of an audio device's response to various frequencies. A good audio device can amplify the bandwidth as wide as possible by the same multiple.

In order to reduce errors, a microphone is placed on each of the two earphones. Since there is no microphone of proper height

A simple bracket was made. In later tests channnel1 and channnel2 Test results corresponding to left and right channels respectively

According to convention, white noise is generally used to test the frequency response of an audio device. White noise is characterized by the same amplitude of all frequencies

after HD500 Time domain signal and spectrum of white noise after playing

You can see that 300~8000Hz about, HD500 The frequency response of

Total harmonic distortion (THD) is a very important index of power amplifier, so called high fidelity (i.e HiFi ）Amplifiers, harmonic distortion generally 1% following. For signals with a single frequency passing through the audio equipment, besides the response of the same frequency (fundamental wave), harmonics of other frequencies will also be generated. The square root of the ratio of the power of these harmonics to the fundamental wave power is the total harmonic distortion, which is usually abbreviated as THD （ Total Harmonic Distortion ）, also become THD-Noise . Due to time constraints, I only tested 1000Hz Sinewave THD

after HD500 Sine wave time-domain signal and spectrum of

except 1000Hz In addition to the fundamental wave of 2K ， 3K ， 4K ， 5K ， 6K ， 7K ， 8K ， …… Harmonics, calculated according to the formula THD （ 1000Hz ） =0.80%

At the same time, Xiao Bian is also right 300Hz The response of square wave and pulse signal is tested, and the square wave original signal

after HD500 Post 300Hz Time and frequency domain response of square wave

Pulse original signal

after HD500 Response after

Although the square wave response and pulse response also have some distortion, and the bass and high-frequency parts need to be improved, the overall effect is still very good, and the quality is good!

v Summary

On the whole, tasting HD500 It is a very good headworn wired headset. As a HiFi The entry-level product basically ensures good audio quality on the basis of reducing the product price, and fully meets the requirements of ordinary audio and video entertainment. For consumers who do not have particularly high requirements for audio quality, it is a very worthwhile audio device!