The simplest reason is: the output level of the mobile phone headphone port is too low, or it can also be said that the output power of the mobile phone headset is too small.
Use a computer or CD player to connect the HiVi M200MKII active speaker. The volume knob is between half and three o'clock. In a range of more than ten square meters, you can get satisfactory sound pressure and play some noisy sounds. Rock music may feel too loud; but after switching to the headphone port of a mobile phone and adjusting the volume to the maximum, it still feels that the sound is not loud enough, the treble cannot be raised, and the low frequency is soft and weak.
Of course, there are also reasons why other friends said that the digital-to-analog conversion is not working, the sound card is not working, etc.
My solution is: use Marantz Digital to perform digital-to-analog conversion and play lossless music to get a sound effect close to CD quality.
The mobile phone is not a device specifically designed for music playback, and it is not optimized according to the requirements of music playback. This is determined by the design goals.
There are several technical reasons for poor sound quality. First of all, in the digital processing part, ordinary mobile phones usually use CPU for DSP processing, and a few mobile phones use special chips for DSP processing, but the CPU or DSP processor There is a slight error in the frequency locked between the clock and the audio file. It is called jitter in the professional world. Simply put, it is because the clock is inaccurate and the do sound is not pronounced correctly when it is pronounced. It is always a little earlier or a little later. If you step on it incorrectly, it will naturally look awkward and sound uncomfortable. Secondly, in the digital-to-analog conversion part, that is, the decoding part, the conversion accuracy of the mobile phone is not high. For example, the current value at a certain point in time recorded in the audio file is 0.05 amps, but the current converted by the mobile phone is always a little larger or a little smaller, and the sound sounds a little higher or a little lower, and the pitch is out of tune, which of course sounds very uncomfortable. If the rhythm is wrong and out of tune, the sound quality will of course be bad!
No matter how subjective the sound quality is, objectively speaking: audio is a system project. I remember that an experienced driver once summed it up brilliantly as "the leader and the tail". Audiophiles start from the power supply introduction (such as single-line balancing and so on) to the audio source and wires (input and output), digital-to-touch conversion, power amplification, sound unit and placement. Finally, let’s tinker with the golden listening environment. It’s rare to play every aspect to the extreme!
The mobile phone is not a hifi player, so the audio signal output through the headphone jack of the mobile phone is decoded and output by the audio amplifier of the mobile phone and the playback software app. Of course, the sound quality is very poor. If you need to send signals from the mobile phone to the power amplifier, there are two ways, one is through Bluetooth, and the other is to output the signal to the USB port of the decoder through the USB port of the mobile phone. This requires a Bluetooth decoder. There are good and bad decoders, ranging from a few hundred yuan to tens of thousands of yuan. If you want better sound quality, you can choose decoders with 9018pro decoding chip, 9028pro decoding chip, 9038pro decoding chip, and 4499 decoding chip.
There is nothing wrong with using a mobile phone as an audio player. As long as you prepare the necessary equipment, plus correct connections and debugging, you can achieve relatively good sound effects.
First, equipment preparation
To use a mobile phone as a player, option one requires a power amplifier, two speaker boxes, and a one-to-two dedicated audio conversion cable. One end of the line is a headphone plug, which is used to insert into the headphone jack to output the audio signal of the mobile phone. The other end of the line is two separated lines, one is a banana plug, which is used to plug into the input hole of the left and right channels of the power amplifier. . Two audio cables are also needed from the output hole of the amplifier to the input hole of the speaker box. Option 2 requires two active speakers (speakers with built-in power amplifiers). You also need a one-to-two dedicated audio conversion cable, and then directly plug the two banana plugs into the input holes of the two active speakers. .
Second, debugging
After the line is connected, first adjust the volume of the mobile phone to 10 15%. Option 1: Turn the volume button of the power amplifier back to "0", then turn on the power of the power amplifier, set the channel to the channel connected to the mobile phone, and then slowly increase the volume until you are satisfied.
Option 2: Turn the volume buttons of the two active speakers back to "0" and turn on the power switch at the same time. Start debugging with one speaker first, slowly increase the volume until you are satisfied, and remember this volume scale. Then use the same method to adjust the other speaker, and keep the volume scale consistent with the previous speaker.
Third, precautions
1. To pursue high volume, adjust the volume knob on the power amplifier or active speaker. The volume of the mobile phone can only be fine-tuned. Increasing the volume of the mobile phone will cause Distortion, and also produces current sound. The poor sound mentioned in the title question is probably related to the excessive volume on the mobile phone.
2. The output from the mobile phone hole cannot be directly connected to the speaker box, because the current output by the mobile phone audio output is too small to drive the speaker, and of course it cannot obtain good sound effects.
As a sound source, mobile phones are divided into two parts: digital and analog. Digital is the audio source format and decoding software. Analog is the circuit that outputs the audio source. The middle process is called DAC digital-to-analog conversion. The digital-to-analog conversion chip used by a good DAC has strong computing power, so the level and detail of digital conversion into analog signals is very good. In other words, high fidelity. Compared with professional players, the hardware configuration of mobile phones is usually low-level. In addition, analog output is also key. Usually the analog signal chip after the professional DAC is not responsible for amplification. This requires an op amp to complete. Of course, it is impossible for mobile phones to use audiophile-grade op amp circuits to achieve high-quality output. Therefore, the effect of using the headphone end to output to the speaker will not be particularly ideal. Sometimes it's not even as effective as connecting to an external speaker via Bluetooth.
The reasons are: 1. The lossless music downloaded through the mobile phone app has been compressed and transcoded, so it is not as good as ripping the track, and the audio source file is not good. 2. Hardware decoding and amplification are barely enough for entry-level headphones worth around a thousand yuan. Speakers are for listening to noise, but the hardware is not good enough. 3. The transmission port is too weak, what a huge sound loss. 4. Even with soft decryption, the players that can be installed on mobile phones can hardly decode 1-2G high-quality audio source files, let alone 4G compressed master files. I tried to barely decode a file of about 300MB, but it occasionally got stuck. 5. I am sure that there is no femtosecond clock on the mobile phone, so it cannot be synchronized. There are many other reasons
This is caused by the playback defects of the mobile phone itself. First of all, after passing through the mobile phone, the lossless is no longer lossless, especially the Android mobile phone, which has congenital defects.
The second is that the output power is too low and the speaker cannot be driven at all.
The headphone output level is too high! If you want to get good results, connect an 8 ohm resistor to the output end, and then connect a 10-50K resistor in series. The sound will be greatly improved!
The built-in sound card of the mobile phone is too low-grade. Music phones have built-in HiFi decoding chips, and the sound quality is much better.