Owners of smartphones Xiaomi, Redmi and POCO They often wonder what a small circular hole is on the top of the body, and it can be next to a headphone jack, an infrared port, or it can be the only thing on the end. Many users mistakenly take it for a microphone for noise reduction or even for a hidden slot for the sound. SIM-map.
In fact, the functionality of this element depends on the specific model of your device and the year it was released, in some cases it is a really secondary microphone, in others it is an IR port for controlling household appliances, and in others it is just a decorative element or a place where the sensor is installed. Understanding the purpose of this hole is critically important so that you do not damage the device when cleaning or using special accessories.
In this article, we will analyze in detail all possible options, explain how to independently determine the type of hole without opening the case, and tell you why it should not be glued or ignored when servicing the gadget.
Main purpose: noise reduction microphone
The most common reason for having a hole on the top of a smartphone is to install an additional microphone. Unlike the main microphone, which is located at the bottom next to the charging port and is used to transmit your voice, the top element is responsible for picking up ambient noise. The noise reduction system analyzes the background hum and cuts it off, making your voice clearer to the interlocutor.
The technology is based on comparing signals. The main microphone picks up voice and noise, and the top microphone picks up noise, the processor processes the difference and produces a clean sound, and if you seal that hole with a case or a finger, the quality of communication can drop dramatically, and the person will hear you from the barrel.
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When buying a protective case, make sure that the cutout on the upper end exactly matches the microphone hole, otherwise you will lose the noise reduction function.
You can tell if the hole is a microphone, visually, and you can usually see a small mesh or membrane inside that protects the inside from dust, and it's a small hole that doesn't shine with infrared light when it's activated.
Infrared port (IR-Blaster) on the upper end
Many Xiaomi and Redmi models feature an integrated infrared port that turns a smartphone into a universal remote control, most often a black round window located on the upper end next to or instead of the microphone hole, through which the phone sends signals to TVs, air conditioners and other equipment.
It's pretty easy to tell the IR port from the microphone. First, there's no grid inside the IR port, there's an LED that emits light in a spectrum that's invisible to the human eye. Second, if you turn on the Mi Remote app and point the top of the phone to another smartphone's camera, you'll see a faint purple glow when you press the buttons.
How to check the IR port without a second phone?
The presence of this port is a huge advantage of the Xiaomi ecosystem, which allows you to control equipment even without access to the Internet, unlike Wi-Fi remotes. However, if you use thick protective glass or bumpers with an overlying top, the functionality of the remote can be disrupted.
Sensor of proximity and illumination: hidden functions
In some configurations, especially those with waterfall screens or droplet cutouts, sensors can be placed on the end. Although more often the proximity and illumination sensor is located at the top of the front panel, in rare cases, engineers place additional sensors in the end hole for better calibration.
If the hole is used as a proximity sensor, it helps the screen go out when you hold the phone to your ear while you're talking, and it prevents accidental cheekstrokes, and if you have a light sensor in there, it adjusts the brightness of the screen to the environment, although it usually uses a separate sensor on the front panel.
It's important to keep this area clean. A buildup of dirt, skin fat, or pile from your pocket can cause sensors to malfunction, the screen may stop fading when you ring, or the brightness will jump for no reason.
- 📱 Rinse the upper end with a soft cloth regularly to avoid sensor failures.
- 🚫 Do not use sharp objects (needles, toothpicks) to clean the hole so as not to damage the membrane.
- 💧 Avoid getting moisture into the hole, as there are sensitive electronics.
Decorative element or stub?
In budget models or specific modifications, the hole on the end can act as a decorative plug. Manufacturers often use a single matrix of the case for different versions of the smartphone. If the expensive version has an IR port, and in the cheap version it does not, the hole can be left to preserve the symmetry of the design or close with a plastic plug from the inside.
Sometimes users mistake the functional opening for the technological gap needed for assembly or the space for the antenna, in which case it can be just plastic or metal without any electronic components, trying to "unplug" such a hole will not lead to anything, except damage to the housing.
To avoid guessing, it is better to refer to the technical documentation of a particular model on the official website or in the Mi Specs application. There is always indicated the presence of an infrared port and the number of microphones.
How to accurately determine the type of hole: step-by-step instructions
If you are still not sure what is in the hole on your device, we suggest using a simple diagnostic manual to help avoid errors and understand the real possibilities of your gadget.
☑️ Diagnostics of the upper hole
The first step is visual inspection. Use a magnifying glass or a macro shot on another phone. If you see a grid, it's a microphone. If there's a black glass, it's probably an infrared port. The second step is a software test. Record the video with a tape recorder blowing into the hole. If there's a sound, it's a microphone.
The third step is to check the IR signal, and even if you don't have a second phone, you can try to control the hardware, point the phone at the TV, and try to find it in the Mi Remote app, and if the remote works, there's no question, it's an IR port.
⚠️ Warning: Never attempt to clean the hole with high pressure compressed air, which can damage the microphone membrane or move the IR port lens inside the case.
Comparative table of the functionality of the holes
So to be able to navigate the types of holes quickly, we've developed a composite table that will help you distinguish one element from another by the way you look and behave.
| Type of element | Appearance | Location. | Function |
|---|---|---|---|
| Microphone | A net or a little hole | Often one, sometimes two. | Noise suppression, sound recording |
| IR port | Black round glass | Strictly in the center or at the edge | Managing equipment (remote) |
| Sensor. | A little-noticeable window | Near the microphone. | Lighting measurement, approximation |
| Stubblock | Plastic in body color | Symmetrically functional | Design, body unification |
As you can see from the table, the IR port always looks like a dark lens, whereas the microphone has a more open structure, and the sensors are often masked by the color of the case, making them almost invisible.
Problems and solutions
The most common problem with the top hole is pollution, and the dust that gets stuffed into the microphone makes the sound deaf, and in the case of an IR port, a layer of fat can block the signal, and this is solved by a gentle brush with a soft toothbrush.
Another problem is software failure. Sometimes the microphone stops working after a firmware update, which is when you reset or check the permissions in the Settings menu → Privacy → Privacy → Privacy → Permissions Manager. Make sure the right applications are given access to the microphone.
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If the sound has not improved after cleaning the hole, the problem may be in the software or hardware breakdown of the membrane.
In rare cases, the hole may be physically damaged (hit, fall), if the IR port is affected, it will simply stop operating the equipment, and if the microphone is damaged, the interlocutors will complain of silence or severe interference.
⚠️ Warning: Using adhesive to fix the microphone grid is strictly prohibited.The adhesive hardens and permanently disables the component.
The impact of accessories on the work of upper modules
A misfitted case is the number one enemy for upper end functionality. Tight silicone bumpers with high sides can block the microphone hole or shift the trajectory of the IR signal, which causes the phone to "not see" the remote or transmit sound poorly.
Security windows can also be a bad joke if they have a black frame that goes into the area of the sensors. When installing such glass, the smartphone may not correctly detect the approach to the face, and the screen will not go out during a conversation.
- 🛡️ Choose cases with accurate cutouts for the model of your smartphone.
- 👓 Glass treads should have special cutouts for the speaker and sensors.
- 🧹 Remove the cover regularly to clean accumulated dirt in hard-to-reach places.
If you notice that after buying a new case, the sound has gone missing or the remote has stopped working, the first thing to do is check whether the accessory covers important holes. Sometimes it is enough to cut the silicone a little or replace the accessory.
Can I seal the hole if I don’t use the IR port?
Frequent Questions and Answers (FAQ)
Why is the water in the hole dangerous?
Can I switch the microphone to another one?
Why do you need two holes next to each other?
How to check if the IR port works without equipment?
Why is the hole black inside and not silver?
⚠️ If liquid gets into the hole, do not turn on the phone to check the operability of the speakers or microphone - this can finish the device completely.
Understanding your smartphone's device allows you to use it to its full potential. The top hole is not just a design detail, but an important communication and control hub. Keep it from dirt and damage, and it will last the life of the gadget.