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.
Latency Speech Test: 0 ms
Latency Speech Test: 50 ms
Latency Speech Test: 100 ms
Latency Speech Test: 150 ms
Latency Speech Test: 200 ms
Pattern and Speech test
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.
Bluetooth Latency Test
What it is:
The Base RF latency or the default sub-band coding (SBC) of most Bluetooth headphones.
When it matters:
When watching videos a high latency can cause sync issues between the images you see and the audio you hear.
50ms or less
Base latency refers to the default sub-band coding that most wireless headphones use when connecting via Bluetooth. This typically occurs if the headphones do not have any additional codecs like aptX or AAC. It also happens when the codec is not supported by both Bluetooth devices. We also test the Base RF latency for Radio frequency headphones with the same setup but with the RF transmitter in place of the Bluetooth dongle.
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
What it is:
An audio coding algorithm (Codec) that improves bit rate efficiency. It reduces latency and improves sound quality over Bluetooth.
When it matters:
For better sound quality if your often streaming music over Bluetooth. Also it slightly improves latency when watching videos with wireless headphones.
50ms or less
AptX is a proprietary codec by CSR that improves audio quality and bit rate efficiency. This means headphones with aptX sound a bit better and less compressed when playing audio wirelessly. They also have a bit less latency although not as much as with the dedicated aptX (Low Latency) codec.
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.
What it is:
Low latency variation of aptX that significantly reduces sync issues between video and sound when using Bluetooth headphones.
When it matters:
When watching videos or gaming latency is a lot more noticeable than just listening to music.
50ms or less
AptX Low Latency is the fastest of the aptX codecs designed to reduce sync issues when watching videos or gaming. This codec usually performs much better than the standard aptX codec in terms of latency but does not improve sound quality.
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:
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.
Questions & Answers
5 ANSWERED QUESTIONS
For Wireless Headsets that can also be used as wired (i.e. Bose QuietComfort 35) is the latency issue negated when they are used as wired?
Yes, when the headphones are used with a wired connection they have negligible latency (less than 10ms).
I'm interested in the Plantronics Backbeat PRO 2. I'm looking for a transceiver so I could talk back to say a video conference call, not just listen to movies. Do you guys have any recommendations? I couldn't find a solution myself.
We use the Mee audio connect Bluetooth 4.0 transmitter to measure the latency of the Plantronics Backbeat Pro 2. With this transmitter, we achieved 36ms latency, which should be suitable for watching movies and video conference calls.
I'm glad I stumbled across this site. One thing I wish for is the ability to filter for headphones that use USB-C connectors. There would probably need to be a distinction between using it only for charging (in the case of wired headphones), or being able to also use it for listening (e.g., Bowers & Wilkins PX).
Thank you for your suggestion, we will add it to our next testbench.
You guys are the only good source for codec latency metrics. Thank you!
Are you likely to include AAC & APTX HD measurements at a later date?
Yes, once we have a reliable and consistent way to measure AAC and aptX HD we will add them to a testbench update. AAC and aptX HD are more sound quality codecs so they will most likely negatively impact latency compared to aptX LL but having the latency numbers for those codecs as well as their impact on sound quality would be great additions to our testbench.
I noticed that you do not test for aptX HD. The transmitter I use from Inateck supports aptX, aptX HD, and aptX LL. It also has indicator lights to let you know which codec you are using. You might consider switching to that if you want to include aptX HD in your future tests.
Thank you for your suggestion, we are discussing ways to improve the latency test in a future testbench and adding aptX HD latency will definitely be considered. We will try the Inateck transmitter and if it is reliable then it could be a better option than the transmitters we are currently using.