aptX vs SBC: Latency and Audio Sync Differences

What SBC and aptX Mean

SBC (Subband Coding) is the standard audio codec for Bluetooth Classic streaming. The Bluetooth Classic radio is the radio protocol behind wireless speakers and headphones, as the Bluetooth technology overview states. Every Bluetooth audio product supports SBC, whether or not a listing says so.

aptX is a separate codec that some makers support in addition to SBC. When a listing title names aptX, it tells you the product can use that codec for wireless audio. A codec compresses audio so it fits through the Bluetooth radio, and the source device must support the same codec for that connection to be used.

The comparison between aptX and SBC on this site is a comparison of stated details, not of sound or latency. The guides do not measure how either codec performs; they read the words on the title and point you to the maker's page for the rest.

What Latency Means in Bluetooth Audio

Latency is the delay between the moment a phone or computer sends audio and the moment a listener hears it. Bluetooth streaming involves compressing the audio, transmitting it over the radio, and decoding it in the headphones, and each step takes time.

Some makers state low latency on their product pages. Apple's AirPods Max 2 page describes ultra-low latency audio when the headphones connect to a device through USB-C. AIAIAI describes its TMA-2 DJ Wireless and TMA-2 Studio Wireless headphones as having ultra-low latency audio, and its UNIT-4 speakers as compatible with low latency W+ Link.

The amount of latency for any product is not ranked on this site. The guides compare stated details only and do not measure how much latency a product has. For a closer look at how codecs are compared, see the wireless codecs explainer.

Audio Sync for Video

When you watch a show, the audio should arrive at the same time as the picture. If the audio arrives later, speech and picture look out of sync.

Some video players adjust for audio delay automatically; others expect the viewing device to handle the delay. The source device, the codec, and the headphones all play a part in whether sync holds.

A low-latency path is one way to keep audio and video together. A wired connection removes the Bluetooth encoding step entirely, which is why wired headphones are a common choice for video at a desk. The wired versus wireless latency explainer covers that choice in more detail.

What to Look For on a Listing

A listing title may name a codec. If the title says aptX, the product supports that codec as an option alongside the standard SBC. If the title does not name a codec, the product still supports SBC, because SBC is the standard for Bluetooth audio.

A maker's page may also name low latency. When a maker states low latency, the product was designed with that concern in mind. The site's buying guides compare stated details such as fit, connection, and battery figures; latency is not measured by the guides.

• A codec word such as aptX on the title
• A maker's page statement about low latency
• Whether the product also offers a wired mode
• The stated battery figure if you plan long shows

The Source Device Matters

The codec on a headphone listing only matters if the phone, tablet, or computer also supports that codec. The Bluetooth radio negotiates a codec that both sides share; if the source device does not support aptX, the pair uses SBC instead.

Read a codec word on a title as a capability, not a promise of performance in every setup. For a closer look at how low-latency codecs are described on listings, see the low latency codecs explainer. If wireless video sync matters to you, check the maker's page for latency statements and consider whether the product also offers a wired mode.

What a Codec Word Does Not Tell You

A codec word on a title does not tell you how a product sounds, how much noise it cancels, or how long the battery lasts. The guides do not produce measured claims for any of those details; they compare only what a listing states.

A codec word also does not tell you a latency number. No measured latency figure appears on the catalogue listings, so no latency ranking appears in the guides. The maker's page is the place to look for a latency statement.

Wired vs Wireless for Video

Some wireless headphones also offer a wired mode. If a listing says wireless and wired, the product can be used either way, which gives you a fallback for video at a desk.

For a fixed screen, a wired pair avoids the Bluetooth encoding step. For a phone on the move, wireless headphones are the usual choice, and a codec word such as aptX on the title is a detail to check on the maker's page.

What to pick for your situation

Questions

What is SBC?

SBC (Subband Coding) is the standard audio codec for Bluetooth Classic streaming. Every Bluetooth audio product supports it, so a listing does not need to name it. When a listing does not name a codec, SBC is the default.

What is aptX?

aptX is a separate Bluetooth audio codec that some products support in addition to SBC. When a listing title names aptX, the product can use that codec when the source device also supports it. Both sides must support the codec for it to be used.

Does aptX help with audio sync for video?

The guides do not rank codecs for latency or audio sync. A codec word on a title is a signal to read the maker's page for latency statements, not a measurement of sync performance. Latency figures are not printed on the catalogue listings this site compares.

Why does your audio go out of sync with video?

Bluetooth streaming adds a delay between the source and the headphones. Some players adjust for that delay automatically; others do not. The source device, the codec, and the headphones all play a part in whether the sync holds.

Should I use wired headphones for video?

A wired connection removes the Bluetooth encoding step, which simplifies the audio path. Some wireless headphones also offer a wired mode, giving you a fallback for video at a desk. Check the listing for the words wireless and wired.

What should I check on the maker's page?

Look for a latency statement and for the codecs the product supports. Some makers state low latency directly, as Apple does for AirPods Max 2 over USB-C and AIAIAI does for its wireless headphones. The maker's page is the place for details the listing does not print.