There are several reasons why Bluetooth headphones don’t sound as good as wired ones.
Compression
Bluetooth headphones use a compression algorithm for wireless audio transmission. This compression can result in a loss of audio quality, especially with inferior codecs like SBC. Higher quality codecs like AAC and aptX address this problem, but are not always supported by all devices.
So, depending on the codec quality, you can hear differences in a direct comparison with wired headphones.
Latency
Bluetooth has a latency (time delay) due to the time it takes to encode and decode audio signals. This latency can cause problems when synchronizing with video content and can also affect the overall sound quality.
Bandwidth
Bluetooth has limited bandwidth compared to wired connections. This means that the amount of data that can be transmitted wirelessly is limited, which can lead to a loss of detail and resolution in the audio signal.
Interference
Bluetooth headphones can be affected by interference from other wireless devices or environmental factors such as walls or metal objects. This interference can result in a loss of signal strength and overall sound quality.
So do wired headphones always sound better than Bluetooth headphones?
Quite a few years ago, when asked about a difference in quality, we would have answered with a resounding “yes”. This is more difficult to judge in view of current developments. For example, if you consistently rely on the aptX Lossless codec, you will not notice any differences, if at all. In a blind audition, it was thus not possible for us to determine which headphone came with or without a cable.
However, if you are looking for the best possible transmission quality, you should go for wired headphones: With wired headphones, nothing has to be reduced, so simply put, there is no sound degradation here.
High-quality codecs – this is what you should look for when buying a Bluetooth headset.
When buying Bluetooth headphones, make sure that they (and of course your smartphone, tablet, etc.) support high-quality codecs. Why? The higher the quality of the codec, the higher its bit rate. For example, Qualcomm’s aptX Lossless codec can upscale to lossless CD audio quality – depending on the quality of the Bluetooth connection – and users can choose between lossless CD audio (44.1 kHz) and lossy 24-bit audio (96 kHz). But Sony has also developed a technology with the LDAC codec, which can transfer high-res audio content with a maximum transfer rate of 990 kbps. A depth of 24 bits and a sampling rate of 96 kHz currently exhausts what is technically feasible, but unfortunately this codec is currently only found in a few products. For example, the Sony WH-1000XM5, the Huawei FreeBuds 5i or the Soundcore Space A40 by Anker are among the few that support this transmission codec.
If you want to know more, you should take a look at our guide “SBC, aptX and AAC: Bluetooth standards simply explained“. Here we explain what Bluetooth actually is and which codecs are high-quality.
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