Why Auracast Sounds Better: LC3 vs SBC Audio Quality Explained

Bluetooth LE Audio and Auracast™ are often described as “next-generation Bluetooth audio.”
However, the audio quality improvement is not a matter of marketing positioning or theoretical codec design — it is backed by standardized listening tests published by the Bluetooth SIG.

This article focuses on the actual subjective audio quality results comparing the LC3 codec used in Bluetooth LE Audio with the SBC codec used in classic Bluetooth A2DP, and explains why these results matter at a system and application level.

Classic Bluetooth Audio vs LE Audio

Classic Bluetooth audio relies on the A2DP (Advanced Audio Distribution Profile), with SBC as its mandatory baseline codec. SBC was designed primarily for interoperability rather than compression efficiency, and requires relatively high bitrates to achieve acceptable perceived audio quality.

Bluetooth LE Audio introduces a new audio architecture based on:

• Low Energy transport

• A flexible connection and broadcast model

• A mandatory next-generation codec: LC3 (Low Complexity Communication Codec)

Unlike A2DP, LE Audio is designed to operate efficiently at low bitrates while supporting low latency and scalable broadcast audio, which are essential for use cases such as Auracast.

SBC and LC3: Codec Design Perspective

SBC is a subband-based codec mandated by classic Bluetooth A2DP. While widely supported, its coding efficiency degrades rapidly as bitrate decreases, making higher data rates necessary to preserve perceived audio quality.

LC3, the mandatory codec for Bluetooth LE Audio, is optimized to deliver high subjective audio quality at significantly lower bitrates. It is also designed to maintain robustness under constrained link budgets and packet loss conditions, which are common in Low Energy and broadcast scenarios.

The practical question is not whether LC3 is newer, but how much more efficient it is in terms of bitrate-to-quality performance.

How Audio Quality Was Evaluated

The audio quality comparison between LC3 and SBC is based on subjective listening tests published by the Bluetooth SIG, following the internationally recognized ITU-R BS.1116-3 methodology for assessing small impairments in intermediate-quality audio codecs.

Test conditions include:

• 48 kHz full-band audio

• Mono and stereo configurations

• Frame durations of 7.5 ms and 10 ms

• Comparison against SBC operating under typical A2DP configurations

Listeners evaluated perceived audio quality relative to an uncompressed reference signal.

LC3 vs SBC: Key Technical Results

Mono, Full-Band (48 kHz)

• LC3 @ 124 kbps delivers audio quality comparable to the uncompressed reference.

• LC3 @ 96 kbps and 80 kbps delivers higher subjective audio quality than SBC @ 198 kbps, corresponding to the A2DP high-quality configuration.

• LC3 @ 96 kbps and 80 kbps delivers significantly better audio quality than SBC @ 132 kbps, corresponding to the A2DP medium-quality configuration.

Mono, Full-Band (48 kHz)

• LC3 @ 124 kbps delivers audio quality comparable to the uncompressed reference.

• LC3 @ 96 kbps and 80 kbps delivers higher subjective audio quality than SBC @ 198 kbps, corresponding to the A2DP high-quality configuration.

• LC3 @ 96 kbps and 80 kbps delivers significantly better audio quality than SBC @ 132 kbps, corresponding to the A2DP medium-quality configuration.

Stereo, Full-Band (48 kHz)

• LC3 @ 2 × 124 kbps achieves audio quality comparable to the uncompressed reference.

• LC3 @ 2 × 96 kbps and 2 × 80 kbps outperforms SBC @ 345 kbps, the A2DP high-quality stereo configuration.

• LC3 @ 2 × 96 kbps and 2 × 80 kbps provides significantly better subjective audio quality than SBC @ 237 kbps, the A2DP medium-quality stereo configuration.

Source: Bluetooth SIG LC3 codec evaluation based on ITU-R BS.1116-3 subjective listening tests

Engineer TL;DR

Under standardized Bluetooth SIG listening tests, LC3 operating at 80–96 kbps consistently outperforms SBC operating at 132–198 kbps, and in stereo configurations surpasses SBC bitrates as high as 345 kbps.

In other words, LC3 delivers higher perceived audio quality using substantially less data.

System-Level Implications

The significance of these results extends beyond codec comparison.

Lower required bitrates directly translate into:

• Reduced RF airtime

• Improved coexistence in congested spectrum

• Lower power consumption for both transmitters and receivers

• Improved robustness under real-world link conditions

For broadcast-based audio systems such as Auracast, codec efficiency is critical. A lower per-stream bitrate enables a single transmitter to serve a large number of listeners simultaneously while maintaining consistent perceived audio quality and link stability.

Why This Matters for Auracast

Auracast is fundamentally a broadcast audio system, not a point-to-point connection. Its feasibility depends on the ability to deliver acceptable audio quality at scale.

The Bluetooth SIG test results show that LC3 moves Bluetooth audio into an operating regime where:

• High perceived audio quality

• Low power consumption

• Scalable broadcast delivery

can be achieved simultaneously — something that is impractical with SBC-based A2DP systems.

Conclusion:

The audio quality advantage of Auracast is not anecdotal or subjective preference. It is rooted in standardized listening tests demonstrating that LC3 fundamentally shifts the bitrate-to-quality efficiency of Bluetooth audio.

By achieving equal or better perceived audio quality at significantly lower bitrates than SBC, LC3 enables the system-level capabilities that define Bluetooth LE Audio and Auracast — including robustness, scalability, and energy efficiency.

For engineers and system designers, LC3 represents not an incremental codec update, but a structural change in what Bluetooth audio systems can practically support.