Latency is the time it takes for a signal sent from a source to reach its destination. For headphones, this means the delay between the moment the audio is played and when you actually hear it through the ear cups.
Wireless headphones have a lot of advantages over regular wired models, primarily in range (see our article wired vs wireless headphones). Unfortunately, because they depend on a wireless connection to transmit data, they all suffer from latency. This latency will cause sync issues when gaming or watching movies, which is why popular gaming and home theater headphones have a dedicated transmitters to reduce the amount latency. The ideal wireless headphone is a model that's able to deliver on the benefits of a wireless connection without having any noticeable latency.
Our latency test measures the base RF or SBC Bluetooth latency as well as the time delay of additional codecs like aptX and aptX (low Latency).
When it matters
Wireless headphones with high latency will not be suitable for watching movies or gaming. The audio they reproduce will be significantly out of sync with the images in the video.
It may not be a major concern for you if you only listen to audio with your headphones but when gaming or watching videos, the audio you'll hear will not correspond to the images on screen, which can be a frustrating experience. To give you a better understanding of how latency will affect your videos, we prepared a few samples delayed by 0, 50,100,150 and 200 ms.
We measure the base latency of RF and Bluetooth headphones as well as any additional codecs aptX and aptX (low Latency) that may improve their latency performance.
We measure base latency using a Bluetooth 4.0 dongle that does not have aptX or AAC or the headphones dedicated RF stand. The dongle/stand is then connected to a sound card, which supports ASIO (to limit sync issues) and transmits a click-track generated by a digital audio workstation (DAW). The headphones are recorded through a mic that is fed back into the sound card, creating a loop that shows when the audio signal was sent and when it was received in the DAW software. This is done three times and then averaged, to give the final SBC latency number. Typical SBC latency ranges between 150 and 250ms and RF between 20 and 75ms
We measure aptX with a similar set up as that of the SBC sub-band coding latency. However, in this case, we use a Bluetooth 4.0 dongle with aptX support and measure the feedback delay. This means we measure when the headphones receive the input signal and compare it to when the signal was sent. This test is also done three times and average to get the final aptX latency number. Typical aptX latency ranges between 50ms to 150ms.
Like the SBC and aptX latency test, a click track/input signal is sent to the headphones wirelessly, which is then recorded to determine the delay. For this test, we use a Bluetooth 4.1 dongle with aptX and aptX(LL) support and measure the latency with the DAW software three times to get the final aptX (LL) Latency number. Typical aptX(LL) latency ranges between 30 and 50ms.
What is not included
A few elements that you could care about are not included in the score:
- Bluetooth 5.0
- AAC and aptX(HD) Latency
If you feel there is an item missing that should be included, please let us know in the Q&A section.
Our Latency test measures the delay caused by transmitting data over a wireless connection. For headphones, it's the time it takes for audio to play through the ear cups which might be out of sync when watching videos. We measure the base latency for RF and Bluetooth headphones as well any latency improving codecs such as aptX or aptX (LL). The higher the latency, the more delay there will be between the images you see and what you hear, which could significantly reduce your movie or gaming experience. However, depending on your choice of headphones and listening habit it may not be as big of an issue for you.