How USB-C headphones work (2024)

On September 23, 2021, the European Commission released a proposal that would make USB-C charging mandatory on most electronics (like smartphones and headphones) sold in the EU. This news will likely expand the market for USB Type-C headphones and dongles further, since smartphone manufacturers all but abandoned the tried and tested 3.5mm connector for the standard. The move to a primarily digital interface for headphones remains controversial, and the costs and ecosystem compatibility problems have proven more than a little problematic.

If you’ve wondered just what the differences between USB-C and traditional headphones are, then look no further. We’re going to dive into how this technology works: its pros, cons, and pretty much everything else you’ll ever want to know.

Editor’s note: this article was updated on March 22, 2023, for changes to update style, and add user-submitted FAQ.

What are the pros and cons of a digital audio interface?

The whole purpose of moving over to USB audio is to go digital. That is, to keep the signal in the digital domain for longer before converting to analog, preserving signal quality for as long as possible. Digital devices like smartphones are hotbeds of high-frequency clock signals and power lines—not the type of circuitry that you want to run your high-quality analog audio signals near. Give this link a read if you need a primer on digital vs analog signals.

The main advantage of switching to USB audio is that it moves the DAC and amp components from inside the source (smartphone) to the inside of the headphones or dongle. As each audio peripheral can now have its own DAC circuitry, this is more expensive in the long term. But now that headphone companies are in charge of these circuits, customers should experience better quality audio just by purchasing good headphones—in theory.

Music remains in digital form across the cable with USB Type-C headphones. But this requires more components than the old approach.

The move also introduces additional complexity when it comes to sending the audio signal. USB audio data transmits information as packets rather than a continuous stream of PCM audio and also requires a clock signal to keep everything in time when the data reaches the DAC. After USB transfer, data packets are decoded into a single audio data stream format that a DAC understands, such as I²S. The choice of clock system is actually very important for USB audio.

USB data and clock jitter

There are many ways to send data over USB:Asynchronous transfer is where the audio device’s oscillator determines the synchronizing USB clock and also links this to the speed of the DAC, therefore minimizing the risk of jitter. Jitter, by the way, occurs when a clock goes out of sync, causing data to be misread or miswritten.

How USB-C headphones work (2)

Unstable clocks jitter, which results in data read and write errors, and DAC timing distortion.

USB audio isn't just about data transfer, it also includes digital communication for on-device features.

Isochronous transfer is popular because higher speed data transfer allows for data to be re-sent in time if an error is detected. The latest USB 3.1 specification includes a more robust synchronization scheme for these transfers, and is an optional feature for the latest USB Audio Class 3.0 specification for audio products. USB audio isn’t just about data transfer, it also includes digital communications for on-device feature controls that you don’t get with analog audio. For that, we need to know a little more about USB Audio Classes.

What are the USB Audio Classes?

The USB Audio Class specification allows a USB device to identify itself as an audio peripheral. This specification also determines a USB device’scompatibility with a range of specific USB functions and communication types suitable for audio. USB Audio Classes predate USB Type-C and work with both the new and legacy connectors.

Digital data for both audio and function controls are transmitted over the data (D+ and D-) USB pins, although there are a few different specifications that define exactly what information to transmit over those pins. Using a USB on the go (OTG) cableto turn external audiophile DACs into host devices has been a bit of a workaround for a while. However, this only transfers audio data. The best way to use the full set of available audio features over a USB port is tobuild devices, like headphones, that work with the USB Audio Device Class (ADC) specifications. Version 1.0 dates back to 1998 and still works well, but the latest 3.0 revision is far more interesting and important for modern headphones.

USB ADC 1.0 and 2.0

All of the audio class specifications break down into three parts—AudioControl for inner function controls like volume or EQ, MIDIStreaming for MIDI data, and AudioStreaming for the PCM audio data both to and from the headphones. Android smartphones running 5.0 Lollipop or newer all support a subset of version 1.0 as a minimum, and many newer devices support class 2.0 and even 3.0 too.

One big difference between Audio Class 1.0 and 2.0 is speed. Version 1.0 existed before High-Speed USB 2.0. Data speeds cap at 12Mbps with USB 1.0, and ADC 1.0 maxes out at 8.2Mbps. Audio Device Class 2.0 works with speeds up to 480Mbps and uses up to 196.6 Mbps for audio. Both are more than fast enough for high-quality stereo music streams and the biggest difference is in the number of channels each can support.

USB Audio Class 1.0 supports up to 32-bit/96kHz or 16-bit/192kHz stereo audio. However, Android’s default implementation caps this to 24-bit/48kHz. Version 2.0 boosts this to 32-bit/384kHz, although this faster speed comes at the cost of higher power consumption making it less ideal for portable devices like smartphones.

How USB-C headphones work (3)

USB IF USB Audio Class transfers more than just audio data. The AudioControl interface grants control over headset features like microphone volume, channel mixing, and even on-device EQ, if supported by the headphone.

New USB ADC 3.0

USB Audio Class 3.0 isn’t any faster for stereo audio, but it does offer some important new features for modern headphones. The standard reduces power consumption with support for power idling between isochronous data transfers, making power consumption more competitive with the traditional 3.5mm jack. It also offers a more robust packet error protection scheme, making it less susceptible to jitter and data loss.

Audio Class 3.0's main benefits are better power efficiency and support for advanced processing features.

The standard mandatesUSB Basic Audio Device Definition (BADD) declaration for hardware, which defines common features sets like microphone controls. The standard also introduces moreAudioControl functions for advanced features like noise and echo cancellation. This is important to correctly expose these features to software over USB controls so that music player apps can take control of these functions without the need for proprietary software or USB communication methods.

Can you get analog audio over USB?

USB Type-C audio connections don’t actually have to be digital: you can actually get analog audio out too. The USB standard also supports “Audio Accessory Mode”, whereby the D+/D- pins switch roles to support analog audio signals—again, this isn’t new to USB Type-C. Many phones with and without the new connector are designed to handle the negative voltage swing of the analog audio signal. AccessoryMode is popular with older USB audio dock devices and the Android Open Accessory Protocol 2.0 with audio support has been around since Android 4.1.

How USB-C headphones work (4)

Texas Instruments An example of how audio accessory mode is supported over USB Type-C.

Routing audio this way is no better than the old system using the 3.5mm audio jack (since digital signals aren’t employed) and is often worse: the output devices used aren’t generally optimized for audio, and the analog signal is close to noisy power and high-speed data lines, potentially reducing performance due to interference and noise. Unfortunately, many new USB Type-C dongles and headphones do make use of this mode, and support isn’t universal in the smartphone space either. This leads to many compatibility problems, which makes for a frustrating end user experience.

What’s the difference between active and passive USB-C adapters?

All of the above applies to the new market for USB Type-C headphones, as well as USB Type-C to 3.5mm cables, dongles, and adapters, whichalso come in both active and passive varieties.

Audio Accessory Mode is not universally supported by smartphones, causing headphones and dongle compatibility issues.

The former benefits from digital audio and an integrated DAC, just like “digital” USB headphones. These can support USB Audio Class specifications too, although most of them will just implement a DAC and amplifier rather than any post-processing components. Passive dongles work by exploiting USB Audio Accessory Mode to obtain an analog signal from your smartphone, and as such are usually the cheaper, and—as explained above—lower quality option.

As you can see, there are a lot of options in the USB audio space which can and has led to confusion. Unfortunately, there often isn’t an easy way to tell how nicely two devices will play with each other, or which features are supported. For now, your best bet is to dive into product spec sheets and try to find out which version of USB Audio Class it supports. Either that or just stick to Bluetooth headsets!

Frequently asked questions

If they’re set up without an app in mind, just connect the headphones to your phone’s USB-C port and the other end to your headphones and that should take care of it. You may need to enable an app to communicate with your headphones, but it should become clear pretty quickly if your headphones are compatible.

Yeah, USB audio is decent when it works—it avoids some headaches introduced by wireless tech at the expense of wired ones, but that’s not really a big deal if you’re chasing audio quality.

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How USB-C headphones work (2024)

FAQs

How do Type-C headphones work? ›

USB-C, in its general form, outputs digital audio instead. In such cases, the headphones or connected device needs to handle the conversion. That's why you find a chip inside some USB-C to 3.5 mm converters. But if the phone comes with a DAC for wired audio, the USB-C can offer converted analog audio output.

How do I enable USB Type-C headphones? ›

Set up your Google Assistant
  1. Plug your Pixel USB-C earbuds into your phone.
  2. Start setup: If you see a notification that says "Pixel USB-C earbuds connected," tap Finish setup. If you don't see a notification, press and hold Home . Then tap Finish headphones setup.
  3. Follow the steps on the screen.

How do I use USB-C headphone adapter? ›

Use Surface USB-C to 3.5mm Audio Adapter
  1. Plug your 3.5mm accessory headphone jack into the 3.5mm port of your Surface USB-C to 3.5mm Audio Adapter.
  2. Connect the USB-C connector on the adapter to the USB-C port on your Surface. The adapter will automatically be set up and ready to go.

Can you listen to audio through USB-C? ›

If your main switching device does not have a headphone jack or Lightning port, you can route external audio into the device using the USB-C port.

Why don't USB-C earphones work? ›

Either the USB-C port isn't connected to the motherboard. This can be from dropping the phone, or from rough treatment plugging and unplugging the connector or, if the port is plugged into the motherboard, the plug could have worked loose. Or it's a strange software problem.

What are the advantages of USB-C headphones? ›

In general, USB-C headsets may offer a slightly better sound quality compared to those that use a traditional 3.5mm headphone jack, because the digital signal can be transmitted more accurately over a USB-C connection.

How do I get my USB headphones to work? ›

How to setup a USB headset with Windows 10
  1. Plug the USB plug into the USB port. Make sure the USB plug is completely plugged into the USB port.
  2. Double check the headset mute button. ...
  3. Open Sound Settings. ...
  4. Set the USB headset as the output device. ...
  5. Set the USB headset as the input device.

Can I use C type headphones on my laptop? ›

An USB-C to USB adapter is included in the pack. This little accessory enables your TYPE-C headphones and its built-in microphone on the PCs which only equipped USB port. It provides you the most compatibility and convenience.

Does USB-C to headphone jack work? ›

A: Yes, the USB-C to 3.5 mm female adaptor does work with headphones that have a microphone built in.

Can you convert headphone jack to USB-C? ›

The USB-C to 3.5mm Headphone Jack Adapter lets you connect devices that use a standard 3.5mm audio plug — like headphones or speakers — to your USB-C devices.

What is USB-C digital audio? ›

This USB-C adapter lets you listen to music from your device's USB-C port using regular headphones. A built-in DAC outputs high-resolution audio and features a Class G amplifier (24-bit/192 kHz).

Do all USB-C cables support audio? ›

USB-C, or USB Type-C, is a 24-pin connector (not a protocol) that supersedes previous USB connectors and can carry audio, video and other data, e.g., to drive multiple displays or to store a backup to an external drive.

How do Type-C earphones work? ›

USB Type-C will transmit digital audio instead, leaving it up to your headphones or other listening device to convert this data and amplify the sound. USB-C can also send analog audio output like the headphone jack, as long as it is implemented in the port and your phone has a DAC for wired audio.

What is a Type-C headphone adapter? ›

The USB-C to 3.5mm Headphone Jack Adapter lets you connect devices that use a standard 3.5mm audio plug — like headphones or speakers — to your USB-C devices.

Does the USB-C to audio jack work? ›

Yes, you can use any USB-C to 3.5mm.

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