How do you connect speakers to a TV? I plugged in ARC, optical, Bluetooth, and 3.5mm one by one, but the old TV was last in line

the TV in the living room was a 55-inch TV bought in 2019. After six years of use, the biggest problem wasn't the picture but the sound. The speakers are pointed down toward the base, and once you sit far away, watching the characters in the drama sounds like they're saliva. At night, you have to turn the volume up to 40 to hear the lines, and next door is the bedroom—if you turn it up, it's noisy. I decided to connect an external speaker, but found it to be more troublesome than I imagined: there were several ports behind the TV, several ports behind the speakers, and each could work, but the pitfalls were completely different. I ran through all four wires one by one and recorded them here, so that for those who also want to add speakers to their TVs, it's a bit easier.

Step one: Flip to the back of the TV and count the outlets; don't rush to place an order

which path to take when connecting an external speaker isn't determined by the speaker, but by what port is behind your TV. Move down the TV or use your phone to turn on the flashlight and look around behind your back, focusing on four key items.

One is the HDMI port, usually two to four. One of the ports may have the three small letters "ARC" or "eARC" printed next to it. The letters are small and need to be closely examined. Some devices have a circle of boxes printed to frame them. This port is reserved for the speakers. The second is the fiber port, a small square hole usually blocked by a small cover, which looks hollow. When viewed in the light, you can see a faint red glow, with "OPTICAL" or "Fiber optic" printed on the side. Third, there's a 3.5mm headphone jack, which is the round jack for phone headsets—some older TVs still have it. Fourth, Bluetooth—this isn't a port. Just search the Bluetooth device list in the TV settings to see if it's available.

my unit, I counted it: among the three HDMI ports, HDMI 2 shows ARC, there's an optical port, there's a headphone jack, and Bluetooth is also found in the settings. Taking all four is a good chance to try them one by one. If your TV is relatively new, you might find that the optical port is gone—in recent years, new TVs have generally cut the optical port, leaving only HDMI. This is the trend; the consequences will be discussed later.

second option: HDMI ARC, which has been the main approach in recent years, but plugging in without sound is the norm

first explain what ARC is. A regular HDMI cable sends the image from set-top box to the TV in one direction. ARC stands for Audio Return Channel, which essentially creates a reverse lane in this cable: whether the TV is installed on the app or plays the video, whether the source is from the TV, phone screen casting , or laptop screen, the sound can flow backward through this cable back to the speaker. One cable handles all the picture and sound; set-top boxes and TV apps come from the speakers without switching back and forth. This is what makes it more respectable than the other channels.

I brought over the active speaker my cousin used at his wedding, plugged in the HDMI cable, and it was silent. The TV speakers are still ringing, but the speakers are quiet. After nearly an hour of fiddling, I realized ARC isn't something you can recognize just by plugging it in; you have to follow all three steps: First, the cable must be plugged into the TV's ARC port. Any other HDMI port is just a regular port and won't send back; Second, in the TV settings, change the audio output from "TV Speakers" to "HDMI" or "External Speakers." My unit has a hidden layer in the sound menu; Third, switch the input source to ARC mode on the speaker side. Not a single step is missing.

there's something called CEC. Different brands call it Anycast+, LG SimpLink, Sony Bravia Sync, and most domestic TVs simply call it HDMI CEC. This switch is for "adjusting speaker volume with the TV remote control." If it's off, ARC can make sounds but the volume keys can't control the speakers, causing the remote controls to clash on both ends. On my first night, I pressed the volume buttons but nothing happened, so I realized it wasn't turned on. Additionally, ARC wiring requires high-speed HDMI cables that support Ethernet; older brands may experience intermittent sound. If all the sounds are correct, then unplug the TV and speakers, let them run for two minutes, then power on. This trick is simple but effective. My speakers rely on this for the second time.

the third path: the main focus of old TVs is fiber optics, so be aware of its bandwidth

I plugged the second HDMI cable into the speaker's ARC port, but this speaker is an old model and the ARC port doesn't work well, so I tried switching to optical fiber. Both ends of the fiber optic cable are plastic square ends. Insert them into the square holes on the TV and speakers. If plugged in correctly, there will be a slight clicking sensation. The first time I plugged in, there was no sound. The reason was typical: the TV settings set digital audio output format to "Auto" by default. The old speakers couldn't switch to Dolby stream, so switching to PCM immediately produced the sound. The difference between PCM and bitstream can be summed up in one sentence: PCM is when the TV first decods Dolby into the most basic stereo before sending it out—everyone agrees; Bitstream is about leaving the unchanged Dolby data to the speaker to decode itself. If the speaker can't fix it, it's mute. It's the same problem as a NAS when playing movies and encountering DTS tracks with no sound. The speaker side can't decode the format, so just try another way to make it sound . Connect a regular external speaker, set up a PCM first, and if it can sound, then talk.

fiber, you need to pay attention to the bandwidth record: both it and ARC have bandwidths around 1Mbps, and can only transmit lossy Dolby Digital 5.1 and DTS 5.1. Surmos and lossless audio tracks are out of the question. If you want lossless TrueHD Atmos, you need eARC, with bandwidth up to 37Mbps—that's HDMI 2.1 standards, and you need to support both the TV and speakers. To put it bluntly: when watching online videos, the audio tracks provided by the platform are inherently lossy compression. Both fiber and ARC are sufficient, so you can't tell the difference; Only those who play lossless tracks like local Blu-ray discs will notice the difference, and for my family's need to "just hear the lines," fiber 5.1 is already a dimensionality reduction strike.

There are two main pitfalls in

fiber optics. First, the cable is sensitive to breaking. If the bending radius of plastic fiber is too small, the light won't pass through. When routing cables, don't use cable ties to tighten them tightly—make them too tight. Second, the trend of cutting fiber ports for new TVs. Before buying speakers, think carefully: if you change TVs in a couple of years and only have HDMI ports, then pure optical input speakers will need to add an adapter.

Fourth Option: Bluetooth is the most convenient, but mismatched lip shapes are a major drawback

Bluetooth is the least convenient for wiring. In the TV settings, enable Bluetooth search, enter pairing mode for the speakers, and connect in seconds. I tested it with a small Bluetooth speaker in my bedroom. Putting sound quality aside, the biggest issue was latency: after Bluetooth encoding and decoding, the sound was 100 to 300 milliseconds slower than the screen. When watching people talk, the mouth moved slowly, especially noticeable when watching the news broadcast—it got worse the more I watched. Some TV settings include A/V sync or audio delay compensation, which can be adjusted back a bit, but most of the time it's not accurate.

so Bluetooth's positioning is clear: it's fine to listen to loud noises, but not for dramas with lots of live streams and dialogues. Its truly suitable scenario is the TV installed in the kitchen or bedroom, playing music or podcasts as background music. The ability to use it without focusing on the screen is perfectly fine—but if the speakers are connected to the NAS to play lossless music, that's a whole different approach. I previously wrote about a of connecting three speakers to the NAS. If you really want to watch TV via Bluetooth, both ends must support protocols like aptX low latency. The Bluetooth of a regular TV and a regular speaker paired together, and the latency is basically unavoidable.

Fifth Path: 3.5mm is the most rustic, but it's the most reliable way for old TVs

After trying the three cables above,

finally pulled out a 3.5mm male-to-speaker cable bought for 3.5 yuan, plugging one end into the TV headphone jack and the AUX input from the speaker on the other. Sounds as soon as you plug it in, zero settings, zero latency, not a single second of hassle. Yes, just that simple.

But this dirtiest path has a deeply hidden pitfall: the volume can't go up. The TV's headphone jack output level is only 0.2 to 0.5 volts, while the ideal input for active speakers is 0.5 to 2 volts. If you plug it in directly, the sound will feel quiet and weak, and your first reaction will definitely be that the speaker is no good, but that's not the case. The correct approach is to set the TV's volume to around 80% as a reference point, then use the knob on the speaker to fine-tune it to the right level. At first, I set the TV volume to 10 and the speakers to half, so the sound was as quiet as a mosquito. Following this order, the sound suddenly became richer. Such a small sequence can make people misjudge the entire set of equipment.

Another feature of

3.5mm is its low sound quality ceiling. The longer the analog signal trace, the more easily it gets disrupted. But on the other hand, if you want to hear the lines clearly, it's more than enough. This zero-latency feature is even better than Bluetooth. If your old home TV has nothing but headphone jacks, don't think it's a loss—this path is just for you.

after connecting, there are two more pitfalls, both related to positioning and remote control

speakers playing isn't the end. The first pitfall is the remote control for the echo bar. The soundbar was originally designed to be placed directly in front of the TV, and the infrared receiver window of the old TV was also in the center of the front. When the speakers were placed in front of the TV, it blocked them tightly. No matter what the remote control pressed, nothing happened. At first, I thought the TV was broken. The solution is either to raise the speaker by two centimeters and stagger the receiver window, or move it half a foot to the side. Most new TVs use Bluetooth remote controls without worrying about interference, so pay attention to older TVs.

second pitfall is the battle over sound output settings. Once the TV's sound output is changed to external speakers, some machines have TV speakers simultaneously, creating reverberation. In the settings, turn off the TV speakers separately; On the other hand, if you unplug the speaker cable, remember to switch the output back to the TV speakers, or else the TV mute will be dumbfounded—I didn't explain when I finished installing the speakers at my dad's house and left, and on the third day he called to say the TV was broken, but the output was still stuck on HDMI.

four routes in order: TVs with ARC ports use HDMI ARC, and one cable is the cleanest; Old TVs without ARC rely mainly on fiber optic paired with PCM; Bluetooth is reserved for listening to background sound; 3.5mm doesn't mind it—zero latency, zero settings, the ultimate backup for old TVs. Before buying speakers, check the back of the TV to check the ports. This step can save you half the money and hassle—and also check whether the TV's network connection should be via WiFi or cable. I've written about this in this article TV networking. Picture and sound are two separate accounts, so don't mix them up and mess around.