If the sound coming from your iPhone sometimes lacks the desired quality, the problem may be due to the device settings, dirty speakers, or even the way the audio is connected and played. For example, muffled sound can indicate contamination in the speaker, and a sudden drop in quality when using mobile data may be related to data-saving settings being enabled.
There are several simple ways to improve iPhone sound quality; from cleaning the speakers and changing equalizer settings to enabling features like Spatial Audio. Some methods also require using an accessory that provides a wired headphone connection and can prevent the quality loss caused by Bluetooth compression.
If muffled sound persists after cleaning the speaker, a hardware issue is likely. In that case, if the iPhone is still covered by AppleCare or AppleCare+, the device can be sent to Apple for service.
Get the best sound quality from your iPhone speakers
Dust and debris accumulating on iPhone speakers can reduce sound quality. To clean the speakers, first turn off the iPhone. Then, using a soft toothbrush, gently brush the speaker grilles at an angle so that contaminants are directed outwards rather than pushed further into the grille.
Using a rubber air blower is another option. By blowing air at an angle into the speaker grille, you can remove contaminants. Special putties for cleaning iPhone speakers can also be used.
If music quality decreases when using mobile data, you can change the playback quality settings. In Apple Music, go to Settings, open the Apps section, and then set Cellular Playback to High Quality.
In Spotify you can also use the app's internal settings. Go to Settings & Privacy and select Media Quality. Under Streaming quality on Wi‑Fi, choose "High" or "Very High." Apply the same settings in Cellular streaming quality and Download quality. To re-download higher-quality audio files, tap Download next to "Update available downloads."
To change audio characteristics such as increasing bass or making the vocalist clearer, you can also change the equalizer settings. In Apple Music, from Settings, go to Apps and then EQ, and choose one of the preset sound profiles.
In Spotify, go to Settings & Privacy, then Playback, and finally Equalizer. After enabling the equalizer, you can choose one of the audio presets.
Get the best sound quality from headphones and earphones
The iPhone has a feature called Headphone Accommodations that allows adjusting sound quality based on the user's hearing profile. Before using this feature, it is better to reset any EQ settings changed in the previous section to their default state.
To enable Headphone Accommodations, open Settings and navigate to Accessibility, then Custom Audio Setup and Audio & Visual, and select Headphone Accommodations. Turn this feature on and tap Customize Audio. Then choose Continue and, by listening to audio samples, select the setting that suits you best.
To have a more immersive listening experience on AirPods, you can also enable Spatial Audio. This feature creates three-dimensional sound and makes audio seem as if it is coming from around the user.
To enable Spatial Audio, open Control Center and tap the audio bar. Then choose one of the options Fixed or Head Tracked. In the latter mode, the sound changes according to the user's head movement.
If you still seek higher sound quality, using wired headphones can be a suitable option for lossless listening. Since Apple removed the headphone jack in the iPhone 7, to connect headphones with a 3.5 mm jack you must use a USB-C to 3.5 mm adapter.
The iPhone's USB port also supports audio transmission. One available option is the Subynanal USB-C to 3.5 mm headphone and charger adapter for iPhone 15 or newer models. This adapter is priced at $9.99 on Amazon and, besides connecting wired headphones, provides simultaneous charging of the iPhone via a USB-C connector.