A crackle in the explosions, a picture that catches every couple of seconds: the two faults often arrive together, and they are almost always dealt with in the same way, by turning everything down at random. That is the best way to spend an hour on it without fixing anything. Sound and picture have separate causes. And within the picture, a regular stutter and an irregular stutter are not treated alike: the first is a frequency problem, and it can be set right; the second is a power problem, and it has to be worked around. It all starts with an observation, not with a setting.
Separate the two before touching any setting
Start a game, turn the sound up, and watch for thirty seconds.
- The sound crackles, the picture is smooth: the problem is audio.
- The picture catches, the sound stays clean: it is video, probably a frequency.
- Both give way together in busy scenes: the machine can't keep up.
The last case is the most frequent and the most poorly diagnosed: because the sound is computed by the emulation core at the same time as the picture, any delay empties the buffer and the output plays silence.
Sound: where the crackle comes from
The buffer is too short
RetroArch does not play the sound at the moment it computes it: it stores it in a reserve expressed in milliseconds, which the audio output draws on continuously. The setting is called Audio Latency (ms). Its default value is 64 ms, and 128 ms on the Android and Miyoo versions, because those platforms cannot hold 64 ms. If the reserve empties before it is refilled, you hear a crackle.
Raise the latency in steps: 64, 96, 128, then 192 ms. In exchange you add delay between the action and the sound, which is noticeable beyond 150 ms. It is a trade-off, not a free gain.
The sample rate doesn't match
Each emulated system produces its audio at its own rate, the machine outputs at its own, and a resampler converts continuously. The Audio Output Rate setting is 48,000 Hz by default, with the Miyoo versions outputting at 32,000 Hz. Two mistakes: forcing a rate the hardware cannot handle, and raising the quality of the resampler on a machine that is already at its limit. RetroArch sets it low by default on modest platforms, and that is not an oversight.
Sound and picture drift apart slowly
A gradual drift, with no crackle, is not a buffer problem but a synchronisation one. RetroArch corrects this continuously with Dynamic Audio Rate Control, which imperceptibly stretches or compresses the sound to keep the buffer half full. Its default margin is 0.005, that is half a percent: beyond that, the correction would be heard as a shift in pitch. The official description of the setting is explicit: disabled, correct synchronisation becomes more or less impossible. Don't turn it off: if half a percent isn't enough, it is the screen frequency that has been declared wrongly.
When it isn't software at all
The headphone socket. A crackle that appears when you move the cable, a channel that drops out, a sound that turns to mono: it is the contact. A frayed cotton bud soaked in isopropyl alcohol, with the console switched off, then a dozen insertions of the jack.
The speaker pushed too far. Many handhelds distort in the last quarter of the volume travel: the amplifier clips and it crackles on the bass. Try it at 60%. If the crackle disappears, it is the limit of the amplification, not a fault.
Picture: regular stutter or irregular stutter
This is the distinction that decides everything else. Take a side-scrolling game and stare at the background.
Regular stutter: a frequency problem
What you see. A jolt that comes back at a fixed interval, like a metronome. The game isn't slowing down: the scrolling simply isn't smooth, and the sound is perfect.
The cause. The game isn't producing its frames at the rate at which the screen displays them. The screen only shows what it has in memory at the moment it refreshes, so some frames go past twice. The pattern repeats, and so does the jolt.
What you set. RetroArch works out its synchronisation from the screen frequency you declare to it, and its documentation gives the formula: the input audio rate equals the game's rate multiplied by the screen's, divided by the game's refresh rate. A wrong value therefore distorts the sound as well. RetroArch can measure the panel's real frequency: use that measurement rather than typing in 60 by hand.
Non-integer scaling gives the same impression without being a frame-rate problem: on a 768-line screen such as the TrimUI Brick's, a 240-line image is enlarged 3.2 times, so some lines are duplicated and others are not. Integer scale corrects this at the cost of black bars. A shader that is too heavy, on the other hand, belongs to the next category; our article on shaders and filters says which ones are expensive.
Irregular stutter: a power problem
What you see. Unpredictable jolts, more frequent in busy areas, often accompanied by the sound giving way. The game really is slowing down.
- The emulation core is too heavy. An accurate core costs far more than a fast one: the essential RetroArch settings cover that choice.
- Thermal throttling. A recognisable signature: smooth for ten minutes, then the stutters set in and never leave, as the machine lowers its frequency to avoid heating up further. A break, and not charging while playing, genuinely make a difference.
- The microSD card. No continuous slowdown, but clear freezes of a fraction of a second when an area loads. What counts is the short, scattered accesses, not the speed printed on the packaging: see our guide to choosing a microSD card. A counterfeit gives this symptom.
- A background task. Box-art scraping, syncing, an update: on Android especially, it shows immediately.
The case of European 50 Hz games on a 60 Hz screen
European consoles ran at 50 Hz, American and Japanese ones at 60. On the NES, the exact values are 50.0070 Hz in PAL against 60.0988 Hz in NTSC. To avoid rewriting the code, publishers let the games run more slowly in Europe, about 16.7% slower, black bars included.
Your handheld, for its part, refreshes at 60 Hz. A game producing 50 frames per second on a panel that displays 60 imposes a ratio of 1.2: one frame in five is held for an extra field, which means around ten duplicated frames per second. That is exactly the regular stutter described above, and no power setting will change it. The gap exceeds the 5% tolerance RetroArch allows itself by default on rate differences, and by far what the dynamic audio correction absorbs.
- Play the NTSC version where one exists: 60 Hz, original speed, no black bars. The only route that removes the cause.
- Force the core to 60 Hz where the option exists: the scrolling becomes smooth again, but the game runs faster than intended, music included.
- Accept the stutter. On a role-playing or puzzle game, it is barely a nuisance.
Diagnostic table
| Symptom | Likely cause | Setting to try |
|---|---|---|
| Short crackles, smooth picture | Audio buffer too short | Audio latency from 64 to 128 ms |
| Sound and picture give way together | Core too heavy | Faster core, shader switched off |
| Gradual sound/picture drift | Screen frequency declared wrongly | Have the real frequency measured |
| Crackle when you move the jack | Dirty socket | Clean with isopropyl alcohol |
| Crackling only at high volume | Amplifier clipping | Stay below 70% volume |
| Regular jolt, like a metronome | Game rate different from the screen | Check the frequency, consider the NTSC version |
| Uneven scrolling, stable frame rate | Non-integer scaling | Integer scale |
| Smooth for ten minutes, stuttering after | Thermal throttling | Take a break, don't charge while playing |
The method
Try a second game from the same system: if it is perfect, the problem comes from the file. Then try a lighter system: if that stutters too, look at the card, the heat or the firmware. Change only one parameter at a time. If the game doesn't start at all, see the fourteen causes of a game that won't start instead; if the stuttering persists, write to us through the contact page, as the guarantee runs for two years.
Frequently asked questions
Does raising the audio latency make the controls less responsive?
No, it only changes the delay between the action and the corresponding sound. Below 100 ms, most players notice nothing; beyond 150 ms, it can be heard on a rhythm game. Raise it in small steps.
Should vertical synchronisation be disabled to remove stuttering?
Rarely, and it often creates another fault: without it, the picture tears horizontally during scrolling. It is on by default in RetroArch, and that is the right setting in almost every case.
Can a shader on its own cause stuttering?
Absolutely, and it is common: the filters that reproduce a cathode-ray screen multiply the number of computing passes on each frame. Disable the shader and replay the same scene. If everything becomes smooth again, you have your answer.
The sound crackles in headphones but not on the speaker. What should I look at?
The software chain is the same in both cases: the fault is therefore almost always a hardware one — a dirty socket, a bad contact or a damaged cable. Try a second pair of headphones. If they crackle too, clean the socket with the console switched off.
Does the 50/60 Hz mismatch affect every system?
It affects the systems from the era of cathode-ray televisions, whose European versions ran at 50 Hz: NES, Master System, Mega Drive, SNES and part of the PlayStation 1 catalogue. The Game Boy and the other handhelds never had a slowed-down version.
A sound or picture fault is almost always corrected by a setting, rarely by changing machine. But if it comes from insufficient power for the systems you are after, our retro handheld consoles are sorted by emulation tier.