1. The music itself is unbearable
No matter how good the system is, if you play heavy metal rock music or chicken music you are too beautiful, most people will not be able to suffer. If played continuously, it is likely to cause strong discomfort. This is not actually a problem of the HiFi system itself, but this phenomenon often occurs.
2. The speakers or headphones are obviously excessive in a certain frequency band
If there are too many high frequencies in the speaker or headphones, or even harsh, "dental sound" and other conditions, it is easy to feel uncomfortable after listening for a period of time. If the low frequency of the speaker or headphones is too much, or even heads, etc., there may even be physiological reactions such as chest tightness and irregular heart rate for the speaker system. In this case of too much low frequency, long-term listening will also cause serious Uncomfortable. In my personal experience, for the high-frequency part, the frequency band where people are likely to feel hearing fatigue is not 3k ～ 4kHz in the equal-loud curve, but 8k ～ 10kHz and above. This is because the test signal of the equal loudness curve itself is not informative to music, and I will write a separate article to explain this in detail later.
3. The sound pressure level of the speakers or headphones is too large
The sound pressure level of the speaker or headphones is too large, that is, the volume is too large. Listening to songs in such an environment will cause people's discomfort, and even the volume will be too high to reach the painful area of human ear hearing.
4. The sound quality of the HiFi system is poor
The sound quality of the HiFi system is poor, including not only the poor sound quality of headphones or speakers, but also amplifiers, players, and audio source rates. If you are an audiophile and are used to lossless music, and then let you listen to 128k MP3, it may be difficult for you to accept, and there will be no mood to continue to listen. If you are used to listening to the bass sounds from a 12-inch or 15-inch high-quality woofer, and then let you listen to the bass of hundreds of small-size speakers that are hard-drawn by EQ, it may be difficult for you to accept.
5. The listener's physical and mental state is not good
As mentioned in the previous point, if you often listen to a system with better sound quality and then let you listen to a system with poorer sound quality, you may find it difficult to keep listening. But if you are not in a good mood when you listen to the sound, then even the best device may feel like noise in good music, and you do n’t want to continue listening.
6. Asymmetry of HiFi system
The research results of Robert Reams show that the asymmetry of the left and right channels is a very important cause of hearing fatigue. Interested friends can go to the AES expert channel to learn more about this research.
In fact, from the perspective of psychoacoustics, the human hearing system is very adaptable. We can adapt to the defects of the poor playback system and frequency. This is why some headphones have poor sound quality and the curve is very non-standard, but there are still people Part of the reason for claiming to be nice because they are adapted to this headset.
But there are some factors that we cannot fully adapt to. One of the most important factors is the symmetry of the left and right channels. Robert Reams' research results are consistent with my personal tuning experience of more than 80 years. Asymmetry does cause hearing fatigue, intolerance, and even discomfort in one facial muscle. This asymmetry of left and right channels includes not only the asymmetry of frequency response and phase, but also the asymmetry of Soundstage in subjective evaluation. To take a more extreme example, if you only wear headphones with one channel to listen to music, you will understand after listening for a while ~
For headphones, I see that many evaluation media have measured the consistency of left and right channels. But the significance of this test is not very great, because both the unit and the final product will have upper limits and lower limits, which is the maximum value of the tolerance of the frequency response of the unit and headphones in different frequency bands (+ dB upper limit and- dB lower limit). This is no stranger to those who have done trumpets. But the problem is that for any headset, we can find samples with good left-right consistency and samples with poor left-right consistency. This phenomenon is difficult to reverse the performance of the left and right consistency of all the headphones of this model through the test of a single sample. This is actually another question of probability. This is also a very important reason why audiophiles will have different opinions on the resistance and resistance of a headset. Unless the headphones are strictly paired at the factory, or the upper limits and lower limits are particularly high, such as noise reduction headphones (because noise reduction algorithms usually require higher unit consistency).
Compared with headphones, the asymmetry of the speaker system has higher repeatability, not because of the speaker itself, but because of the room environment and the positioning and directivity of the speaker. This is particularly prominent in car audio systems, because the distance between any unit and any seat in a car audio system is different. This is also the reason why many professional car audio tuner, in order to adjust the sound source localization, can sometimes sacrifice some timbre. Of course, I have talked about this before. The sound source localization of car audio has nothing to do with the FSB frequency response itself. The tuning process is strongly dependent on subjective evaluation. As for the general household HiFi system, the asymmetry of the room is the culprit. In my previous residence in Suzhou, the asymmetric structure of the living room has caused me a lot of trouble. The impact of subjective evaluations, as early as the 1990s, Dr. Sean Olive has done a series of very detailed experiments.