With the same pair of earbuds, the codec that negotiates the link changes how much data actually crosses the air by more than six times: 160kbps for LC3 at its most compact, 990kbps for LDAC at its widest. A codec is not a device that improves sound — it is the rule that decides what gets thrown away over the wireless hop.
Every figure here comes from published specifications. Sony's LDAC developer site states the 990kbps maximum and the best-effort mode that shifts between 330, 660 and 990kbps, while the per-codec bitrate and latency figures follow Feasycom's codec comparison.
Turning bitrate into a compression ratio
A CD stream is 16-bit, 44.1kHz stereo — 1,411kbps. Dividing each codec's bitrate by that number shows how much of the original survives the wireless link. The ratios and hourly data volumes below are calculated directly from the published specs (1MB = 1,000KB).
| Codec | Max bitrate (kbps) | Share of CD stream (%) | Data per hour (MB) | Stated latency (ms) |
|---|---|---|---|---|
| LC3 | 160 | 11.3 | 72 | under 50 possible |
| AAC | 256 | 18.1 | 115 | 120–180 |
| SBC | 328 | 23.2 | 148 | 150–220 |
| aptX | 352 | 24.9 | 158 | 100–120 |
| aptX Adaptive | 420 | 29.8 | 189 | 80 (40 in LL) |
| aptX HD | 576 | 40.8 | 259 | 150+ |
| LDAC | 990 | 70.2 | 446 | 100–150 |
Two things stand out. First, even LDAC at 990kbps carries only 70% of a CD stream — it is not lossless. Second, measured against a 24-bit/96kHz hi-res source (4,608kbps), that 990kbps falls to 21.5%. Sony's hi-res wireless badge at 990kbps certifies a grade, not lossless transport.
The gap between SBC and LDAC is equally plain in raw volume: Sony describes LDAC as carrying roughly three times the data of SBC at 328kbps, which is exactly the 148MB against 446MB per hour in the table.
990kbps is not what you usually get
LDAC's three modes can be pinned manually, but the default is best effort — the link slides between 330, 660 and 990kbps with connection quality. The bottom rung is the problem. SoundGuys' measurements found the 330kbps setting substantially worse than CD quality, with the noise floor rising to -33dB near the cut-off frequency and performance below both aptX and ordinary SBC across all frequencies.
A codec sets the ceiling on quality, not the sound currently reaching your ears.
So an LDAC badge alone guarantees nothing about 990kbps. A congested 2.4GHz environment such as a subway platform, a transmitter buried in a pocket with your body between the two devices, and battery-saver settings that drop codec bitrate all push the link toward the bottom mode. Forcing 990kbps instead trades that away for dropouts.
Latency, counted in video frames
Latency is quoted in milliseconds, but it is felt in video. One frame of 30fps footage is 33.3ms, so converting the stated figures into frames gives a sense of how far lip-sync drifts.
| Codec | Stated latency (ms) | Frames at 30fps | How it reads on video |
|---|---|---|---|
| aptX LL | 32–40 | 1.0–1.2 | Hard to notice |
| aptX Adaptive (LL) | 40 | 1.2 | Hard to notice |
| aptX Adaptive | 80 | 2.4 | Noticeable if sensitive |
| aptX | 100–120 | 3.0–3.6 | Drifts from mouth shapes |
| LDAC | 100–150 | 3.0–4.5 | Drifts from mouth shapes |
| AAC | 120–180 | 3.6–5.4 | Clearly out of sync |
| SBC | 150–220 | 4.5–6.6 | Clearly out of sync |
The ranking by bitrate and the ranking by latency do not match. LDAC, the heaviest carrier, sits mid-pack on delay, while aptX LL shares aptX's bitrate but cuts latency to a third. If video and rhythm games dominate, low-latency mode support matters before any bitrate number. Most video apps compensate for audio delay themselves, so the real pain points are gaming and live calls.
How LC3 lowered the floor
LC3 is the mandatory codec of LE Audio, and the interesting number is its floor rather than its ceiling. Per SoundGuys' LC3 explainer, the codec runs from 345kbps down to 160kbps and holds around 4.5 on the ITU-R BS.1116-3 listening scale even at its lowest quality setting — better than SBC scores at far higher bitrates. On that scale 5.0 means indistinguishable from the source and 4.0 means perceptible but not annoying.
Sending the same sound with less than half the data also improves power draw and link stability. In hourly terms, SBC's 148MB becomes 72MB under LC3.
What to check on the spec sheet
A codec only applies when both the transmitter and the receiver support it; if either side lacks LDAC, the link falls back to SBC. That fallback is guaranteed because SBC is mandatory on every Bluetooth audio device. A list of codecs on a product page means little until your phone supports transmitting one of them.
Sony notes that it contributed LDAC to the Android Open Source Project so manufacturers can implement it under license — the reason LDAC options are widespread on Android. LE Audio and LC3, by contrast, need hardware support on both ends and cannot be unlocked by firmware alone on older devices.
It is also worth separating compression from isolation. Ambient noise bleeding into the mix is a question of attenuation, not of which codec negotiated the link.
Who each option suits
- If streaming apps are the main source, the file is already lossy before the codec touches it — paying extra for LDAC support buys little
- If 24-bit files stored on the device are the source, the ceilings of LDAC and aptX HD start to matter, at the cost of dropouts when 990kbps is pinned
- If video and gaming dominate, low-latency mode support (aptX LL, aptX Adaptive) outranks bitrate
- If most listening happens while moving, quality in the bottom mode is your real quality — judge by the 330kbps measurements
- If the next device is LE Audio, LC3 is mandatory rather than a feature to look for
