Bluetooth Earbud Latency

ChancedMusic

Curious if anyone has any tips to reduce the latency with Bluetooth earbuds. I just got some Skullcandy Sesh Evos and I’m hoping I can use them for some production when I’m out of the house. However, the latency makes it nearly impossible to play melodies. Of course I can always draw stuff into a piano roll and then hit play, but it would be nice if I could play the on screen keyboard too. I’m trying with NanoStudio 2 and Cubasis 3. Also open to giving Gadget another try if it works better than the others with Bluetooth.

Tarekith

Sadly that's just the nature of Bluetooth, there's really nothing you can do to change the latency.

uncledave

Yeah. Bluetooth audio is digitally compressed to reduce data volume. The bytes must be collected in blocks before compression, so you're always at least one block behind. Unfortunate.

McD

@Tarekith said:
Sadly that's just the nature of Bluetooth, there's really nothing you can do to change the latency.

Gamers want wireless headphones too and PC's usually offer aptX profiles which get latency down to <40 msec. Musicians would probably want less than that. Latency is a
deal killer for for many guitar players NOT using Amp Sims. When you can play 32nd notes you need sonic alignment in milli-seconds.

It's very sad that Apple has not implemented the Qualcomm "aptX" technology. I suspect
Qualcomm would want a fee per device and we're too small a community. But AR/VR devices will require low latency wireless so maybe this will be addressed in a future bluetooth implementation. Apple could design one and make it a standard but Qualcomm might challenge their patent. Of course, someone would have to add the profile/protocol to
commercial silicon implementations.

We'll either get a new wireless networking option for AR/VR or maybe things will go
Wi-Fi with 2-3 msec latencies and no licensing issues, I think. Latency in a VR headset seems like it would cause problems leading to nausea.

rs2000

Only earbuds and headphones with true analog RF or infrared audio transmission have negligible latency.
I have never seen earbuds with an analog infrared or RF link, except you're ready to wear a little receiver box that the earbuds are connected to (wires).

McD

@rs2000 said:
Only earbuds and headphones with true analog RF or infrared audio transmission have negligible latency.
I have never seen earbuds with an analog infrared or RF link, except you're ready to wear a little receiver box that the earbuds are connected to (wires).

Oh yeah. How far it the ear canal from the brain? Wireless assumes energy is transmitted
and then you get into the realm of brain tumors or tumor rumors which is just as bad.

I had a neighbor decide she couldn't live near electric power lines and eventually near the
power meter on her small apartment building. So, she bought a generator and a trailered mobile apartment and bought a piece of land in Arizona off the grid. I suspect she had to move the trailer for the smaller months.

Hope she finds some comfort in these extreme choices. She may find that she just feels bad everywhere and has an immunodeficiency disease. But she swore she always felt better when she went camping. I do too but with a different cause and effect analysis.

I was sleep deprived, caffeine addicted and stressed out for 40 years... good times.

aptX in our devices would be great... maybe Apple can hide the extra cost in their device prices. in the device market Qualcomm competes with Apple as a distant option in
cheaper flip phones. I think there's some qualcomm content required for US cell networks... CDMA vs GSM. I think 5G won that war but Qualcomm probably keeps fighting.

Google shows:
Qualcomm is well positioned as a supplier to the 5G markets.
Qualcomm supplies Apple with modem chips for the iPhone 12
Apple contributes as much as 20% of the company's revenue
The two companies are currently partnered under a multi-year licensing agreement through 2025

Maybe they are chatting about bluetooth chips and protocols too.

Halftone

I wonder if this new codec from google will make Bluetooth audio work

https://venturebeat.com/2021/08/12/googles-soundstream-codec-simultaneously-suppresses-noise-and-compresses-audio/?fbclid=IwAR0AU6G4uJwrloRZ2fkaoGEHuBPjFhTaMnCHyIbIERNzHRdbFwbMsk3R7zI

mojozart

aptX refers to a lot of different things. I've tried several aptX-enabled devices and found them unacceptable for live performance. Confusingly, aptX LL (low latency) has a latency of 40ms.

https://en.m.wikipedia.org/wiki/AptX

I think aptX Live is the ultra-low latency version designed for microphones.

McD

@mojozart said:
aptX refers to a lot of different things. I've tried several aptX-enabled devices and found them unacceptable for live performance. Confusingly, aptX LL (low latency) has a latency of 40ms.

https://en.m.wikipedia.org/wiki/AptX

I think aptX Live is the ultra-low latency version designed for microphones.

Qualcomm has to satisfy the requirements of a myriad of hardware device makers with
7 different profiles implemented.

Apple seems to prioritize audio quality over latency and Qualcomm has a menu of profiles.

This got my attention: "latency of the aptX HD codec can be scaled to as low as 1 ms for 48 kHz sampled audio." I want to experience that in some headphones. I bought a aptX "headphone jack" transmitter and some headphones but never developed the habit of using them. Mostly because the headphones (purchased on the cheap end of the spectrum) gave me great pain to offset the audio improvement.

aptX
The aptX audio codec is used for consumer and automotive wireless audio applications, notably the real-time streaming of lossy stereo audio over the Bluetooth A2DP connection/pairing between a "source" device (such as a smartphone, tablet or laptop) and a "sink" accessory (e.g. a Bluetooth stereo speaker, headset or headphones). The technology must be incorporated in both transmitter and receiver to derive the sonic benefits of aptX audio coding over the default sub-band coding (SBC) mandated by the Bluetooth standard. Products bearing the CSR aptX logo are certified for interoperability with each other.[34]

Enhanced aptX
Enhanced aptX provides coding at 4:1 compression ratios for professional audio broadcast applications and is suitable for AM, FM, DAB, HD Radio and 5.1. Enhanced aptX can handle up to 4 stereo pairs of AES3 audio and compress to 1 AES3 stream for transmit. Enhanced aptX supports bit-depths of 16, 20 or 24 bit. For audio sampled at 48 kHz, the bit-rate for E-aptX is 384 kbit/s (dual channel), 768 kbit/s (quad channel), 1024 kbit/s (5.1-channel), and 1280 kbit/s (5.1 channels plus stereo). Its lowest bit-rate is 60(?) kbit/s for mono audio sampled at 16 kHz, offering about 7.5 kHz frequency response just below that of wideband telephony codecs (which usually operate at 16 kHz sampling rate).[35]

aptX Live
aptX Live is a low-complexity audio codec that is specifically designed to maximise digital wireless microphone channel density in bandwidth-constrained scenarios, such as live performance (a.k.a. Programme Making and Special Events), where the spectrum-efficiency of radio-based devices (wireless microphones, in-ear monitoring, talk-back systems) is becoming a prime operational consideration. aptX Live offers up to 8:1 compression of 24-bit resolution digital audio streams while maintaining acoustic integrity (approx. 120 dB dynamic range) and ensuring latency of around 1.8 ms at 48 kHz sampling rates. In addition, aptX Live also features techniques that aid connection in situations where the bit error rate (BER) is excessively high.

aptX LL
aptX LL or aptX Low Latency is intended for video and gaming applications requiring comfortable audio-video synchronization whenever the stereo audio is transmitted over short-range radio to the listener(s) using the Bluetooth A2DP audio profile standard. The technology offers an end-to-end latency of 32 ms over Bluetooth. By comparison, the latency of standard Bluetooth stereo varies greatly depending on the system implementation and buffering. Solutions are available that use standard SBC encoding/decoding that achieve end-to-end latency of less than 40 ms. The recommended latency for Audio to video synchronization in broadcast television is within +40 ms and −60 ms (audio before/after video, respectively).[36] However, AptX Low Latency requires a dedicated, wireless antenna, so it did not achieve much adoption in smartphones and was retired by Qualcomm in favor of aptX Adaptive.[37] Its main competitor is the LLAC.

aptX HD
aptX HD or aptX High Definition has bit-rate of 576 kbit/s. It supports high-definition audio up to 48 kHz sampling rates and sample resolutions up to 24 bits. Unlike the name suggests, the codec is still considered lossy;[38] however, it permits a "hybrid" coding scheme for applications where average or peak compressed data rates must be capped at a constrained level. This involves the dynamic application of "near lossless" coding for those sections of audio where completely lossless coding is impossible due to bandwidth constraints. "Near lossless" coding maintains a high-definition audio quality, retaining audio frequencies up to 20 kHz and a dynamic range of at least 120 dB. Its main competitors are LDAC codec developed by Sony and LHDC.

Another scalable parameter within aptX HD is coding latency. It can be dynamically traded against other parameters such as levels of compression and computational complexity. The latency of the aptX HD codec can be scaled to as low as 1 ms for 48 kHz sampled audio, depending on the settings of other configurable parameters. aptX HD performs particularly well against other lossless codecs when the coding latency is constrained to be small, such as 5 ms or less, making it particularly appropriate for delay-sensitive interactive audio applications.

Many lossless codecs possess the benefit of a low computational overhead compared to well-known lossy codecs, such as MP3 and AAC. This is particularly important for deeply embedded audio applications running on low-power mobile devices. aptX HD promotes low computational overhead by dynamically selecting the simplest coding functions for each short segment of audio whilst complying with other operational constraints, such as levels of compression and coding delay. Depending on the settings of other scalable parameters, aptX HD can encode a 48 kHz 16-bit stereo audio stream using only 10 MIPS on a modern RISC processor with signal processing extensions. The corresponding decoder represents only 6 MIPS on the same platform.

User metadata and special synchronization data can be incorporated into the compressed format at configurable rates. The latter permits rapid decoder resynchronization in the event of data corruption or loss over communications links where quality of service (QoS) can vary rapidly. Depending on the settings of parameters, decoder resynchronization can occur within 1–2 ms.[39][40]

aptX Adaptive
aptX Adaptive is a next-generation dynamically adjustable audio codec intended for premium audio quality and low-latency. aptX Adaptive’s bitrate scales dynamically between 279kbps and 420kbps. It also works with a shared, rather than dedicated, wireless antenna.[37] Qualcomm claims their new compression algorithm provides a compression ratio between 5:1 to 10:1. This allows aptX Adaptive at 279kbps and 420kbps to produce the same sound quality as aptX at 352kbps and aptX HD at 576kbps. aptX Adaptive supports 16 and 24 bit-depths at 44.1, 48, and 96 kHz sample rates. Hardware aptX Adaptive has end-to-end latency of 80ms,[30] but most phones are using a software transmitter - which does not have any latency advantages over other codecs.[41] aptX Adaptive is also backward compatible with older aptX codecs.[37][42][43][44]

aptX Voice
aptX Voice is a new feature of aptX Adaptive, and is designed to significantly improve the quality of voice for those using Bluetooth accessories to make voice calls. It does this by delivering 32 kHz voice call quality within the Bluetooth Hands-Free Profile.[45]

rs2000

Thanks for doing the research, @McD!

This got my attention: "latency of the aptX HD codec can be scaled to as low as 1 ms for 48 kHz sampled audio."

Does this figure include the time required for Bluetooth transmission, including encryption?

McD

@rs2000 said:
Thanks for doing the research, @McD!

This got my attention: "latency of the aptX HD codec can be scaled to as low as 1 ms for 48 kHz sampled audio."

Does this figure include the time required for Bluetooth transmission, including encryption?

Sorry, looking through the aptX profiles, I don't even see the word encryption used.
Maybe they drop that overhead to lower latency? I'm starting not to care and will keep
using cables for near real audio. We won't see a wireless option until Apple decide to
make one or license the implementation of best available option. MacOS has aptX to serve
the needs of gamers and keep the Mac relevant in that segment. Maybe pressure on IOS game share will get us a solution for music too.

AlmostAnonymous

https://store.kokkia.com/kokkiai10lprodigitalbluetoothsplitterwithswitchableaptxlow-latencyaptxfaststreamsbcforiphoneipadipodtouchwithlightningconnector.aspx

I use the 30 pin one on my ipod classic. Its a player, so i havent really measured latency.
Sound quality is a bit better (i guess), but could be placebo. im not very good at double blind A/B test of flac vs aac, but then again, no one really is.

ChancedMusic

Thanks everyone for chiming in. I really hope then that Apple doesn’t follow through with the “portless” concept that was rumored a year or two ago.

AndyPlankton

Depeneding on where out of the house you mean, and how quiet you need to be, you could always use the speaker when trying to play melodies, maybe not ideal but better than not at all !

ChrisG

Maybe Bluetooth 5.2 will bring something (LE Audio is one thing, no idea about the latency on that though).

Personally I buy the trashiest and cheapest BT 2/3 receiver. I use that when I’m just fooling around with random iOS synths etc on random speakers. The audio is not good, but the latency is low enough to let you mess around.

israelite

The newest implementation of Bluetooth promises 50ms lower latency. Does anyone has any experience with it in the context of making music on iOS?

rs2000

@israelite said:
The newest implementation of Bluetooth promises 50ms lower latency. Does anyone has any experience with it in the context of making music on iOS?

Still too high for my taste (remember that it will add to the latency of the app itself!) when playing live, especially when playing drums or percussive instruments but usually good enough when I'm using step sequencers and piano rolls to compose. But so was the older Bluetooth version.

israelite

@rs2000 said:

@israelite said:
The newest implementation of Bluetooth promises 50ms lower latency. Does anyone has any experience with it in the context of making music on iOS?

Still too high for my taste (remember that it will add to the latency of the app itself!) when playing live, especially when playing drums or percussive instruments but usually good enough when I'm using step sequencers and piano rolls to compose. But so was the older Bluetooth version.

Thanks for your input buddy. This technology surely could be improved. Hopefully we will see some progress in the near future. It's really cool to make music on ipad having the headphones and no wires.

dhsherbert

My wife uses BT earbuds (aptXLL) and has no latency issues. The catch is, we run audio from both iPads into audio interfaces and each interface is routed to a mixer. The headphone audio from the mixer is routed to a headphone amp that we both use for our IEMs. Her channel has a BT transmitter that links to her earbuds. We were already using the audio interfaces for our performances, so the addition of the transmitter was a small cost increase to our existing setup.

Samu

When we're down to 20ms for lossless BT audio I'll re-consider it.

Why 20ms? Because that's a latency I'm quite used to dating all the way back to the C64 / Amiga Trackers where 'everything' got updated each frame at 50 frames per second...

rs2000

@israelite said:

@rs2000 said:

@israelite said:
The newest implementation of Bluetooth promises 50ms lower latency. Does anyone has any experience with it in the context of making music on iOS?

Still too high for my taste (remember that it will add to the latency of the app itself!) when playing live, especially when playing drums or percussive instruments but usually good enough when I'm using step sequencers and piano rolls to compose. But so was the older Bluetooth version.

Thanks for your input buddy. This technology surely could be improved. Hopefully we will see some progress in the near future. It's really cool to make music on ipad having the headphones and no wires.

You're welcome!
Yes, wireless is cool.

A few numbers:

Source:
https://avantree.com/eu/knowledge-base/general-different-bluetooth-codecs-latency/?___store=eu&___from_store=default

AlmostAnonymous

@dhsherbert said:
My wife uses BT earbuds (aptXLL) and has no latency issues. The catch is, we run audio from both iPads into audio interfaces and each interface is routed to a mixer. The headphone audio from the mixer is routed to a headphone amp that we both use for our IEMs. Her channel has a BT transmitter that links to her earbuds. We were already using the audio interfaces for our performances, so the addition of the transmitter was a small cost increase to our existing setup.

If you wanna run AptXLL straight out of the iPad: https://us.creative.com/p/accessories/creative-bt-w3
This bypasses the internal BT of iOS.