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Comment by filoeleven | Hacker News Reader

> That would mean losing the USB-C connector and going all-in on wireless charging and syncing data with the cloud. The world is probably ready for this change.

Not if you make any kind of music with an iOS device. AirPods reportedly come in at ~160ms, which is way too high for playing anything live. There are dozens of great apps, and ways to link them all together into a robust setup. I'm still mad about the missing headphone jack, but there are USB devices for that. Bluetooth needs to get to reliably under 50ms for it to be viable.

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> Not if you make any kind of music with an iOS device. AirPods reportedly come in at ~160ms, which is way too high for playing anything live.

That latency is why Apple’s been preparing to switch to UWB for wireless audio, which is one of the reasons they’ve shipped UWB on nearly all iPhones since the iPhone 11.

UWB audio latency will be far under 50ms for uncompressed/losslessly-compresssed audio.

I remember reading UWB audio latency to be under 10ms which is bonkers consider you cant even get a pixel to print out on screen End to end under that time in most cases. Input Lag, OS Lag, GPU Frame Buffer and DisplayPort / HDMI Lag + Display Panel Lag.

But that was quite some time again we still haven't seen any standard for UWB Audio. Meanwhile WiFi Audio is out already and seems to do better than most expected.

Since you mentioned the 3.5mm headphone port: I recently found out that USBC audio accessory spec was deprecated in 2023. Means those cheap usbc to 3.5mm adapters are going to be useless soon since there is no obligation to support audio through usbc. Only the relatively more expensive DACs remain.

https://x.com/nileshtrivedi/status/1901512841318072572

(I am not the tweet author)

On the bright side, the official apple adapters are $10 and have a legitimately alright DAC in them (including mic input). I picked up a couple to use with pcs and laptops since I generally have better luck with the OEM apple adapters vs the onboard audio (which usually applies weird EQ and FX - looking at you, Dell).

Right, but the cheapest ones with a DAC are $4 on AliExpress.

I don't know whether they also do ADC for the mic input.

The numbers per [1] are:

- 243 ms for AirPods 4 ANC

- 215 ms for AirPods 4

- 185 ms for AirPods Max

- 160 ms for AirPods Pro 2nd gen

Per [2] lowest you can get with properiary dongle is 11ms, and with Bluetooth using SBC, which AirPods use, 85ms. Lowest latency possible using aptX LL Bluetooth headphones is 54 ms. For comparison, wired headphones bring it to as low as 0.1 ms with analog plug and 8 ms via USB

[1]: https://www.rtings.com/headphones/reviews/apple

[2]: https://www.rtings.com/headphones/tools/table, search for "latency" in custom columns

>wired headphones bring it to as low as 0.1 ms

I love this. Didn't know it could go down to 0.1ms.

There is no physical reason for signals to take that long to play in your earphones. Signals across the ocean take less time to transmit.

I am so surprised that a trillion dollar company cannot spare the resources to fund a replacement standard for Bluetooth. When clearly Bluetooth can't be fixed.

This might not be enough reason for the full extent of 160ms, but I'd imagine something like, from low to higher latency impact:

- Digitized music needs a DAC, and this conversion takes non-zero time (few us) - Compressed data is frequently chunked, thus not realtime (few ms) - Data streams are buffered, because the channel (wireless) is quite lossy and may need multiple retransmissions. (few ms more)

> - Digitized music needs a DAC, and this conversion takes non-zero time (few us)

Digital musical instruments exist who also need DACs and they produce near real time audio.

> - Compressed data is frequently chunked, thus not realtime (few ms)

This is a problem with the limited bandwidth of Bluetooth. If Bluetooth had more bandwidth, you wouldn't need to compress as much or at all.

> - Data streams are buffered, because the channel (wireless) is quite lossy and may need multiple retransmissions.

Again a problem with Bluetooth. You can play computer games over wifi with others across the world with less than 30ms of ping. If you have more bandwidth, you don't have to retransmit. You just use an error-correcting code.

I wouldn't fully blame Bluetooth. Part of the problem with streaming audio is how you tolerate lag. Playback requires a constant sample rate of audio but your network is not guaranteed to deliver data at a constant rate. Designs need to accommodate for this and one of the solutions is to have larger buffers to tolerate some network lag.

For live music, as thread OP wants, you can simply switch to a different transmission mode with minimal buffer. It would then be up to the user to ensure direct line of sight between the receiver and transmitter, and do other things necessary to ensure good signal quality.

Active noise cancelation is undoubtedly a factor. You can't cancel noise in real time.

Also, the market doesn't care about latency.

The primary problem with Bluetooth is that you can't simultaneously transmit high quality audio and receive high quality audio. There isn't enough bandwidth to do this. Apple kinds of works around it by using the mic of a nearby device, but this is less than ideal.

A new standard would fix this problem by increasing the bandwidth.

And also not if you value your battery life and good charging speeds.

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