aptX HD is Qualcomm's high-bitrate Bluetooth codec: 576 kbps of bandwidth carrying 24-bit audio at up to 48 kHz. The official spec sheet also lists THD+N of -80 dB and SNR of 129 dB, and Qualcomm's product directory covers phones, headphones, transmitters and more. Direct latency numbers are scarce: RTINGS dropped aptX HD from its bench, and the classic aptX fallback measured 316 ms on Android. iPhones negotiate AAC and SBC only.
Figures on this page were checked September 2026. Every table row carries its source and access date.
Spec summary
aptX HD is Qualcomm's high-bitrate Bluetooth codec, documented on Qualcomm's official aptX HD page with a full technical specification sheet.
| Field | Value | Source / as of |
|---|---|---|
| Developer | Qualcomm (Qualcomm Technologies, Inc.) | aptX HD official page, 2026-09-22 |
| Maximum bitrate | 576 Kbits (48 kHz sampling) | aptX HD official page, 2026-09-22 |
| Audio encoding | 24-bit, up to 48 kHz sampling rate | aptX HD official page, 2026-09-22 |
| THD+N @ 1 kHz | -80 dB | aptX HD official page, 2026-09-22 |
| SNR @ 1 kHz | 129 dB | aptX HD official page, 2026-09-22 |
| PEAQ audio quality | -0.05 | aptX HD official page, 2026-09-22 |
| Compatibility | Backwards compatible with existing aptX products | aptX HD official page, 2026-09-22 |
| Listening evidence | Salford University blind test (2015): 24 participants could not consistently detect a difference between 96kHz/24bit audio and 48kHz/24bit aptX HD | Salford test results as quoted on the official aptX HD page, 2026-09-22 |
The listening-test quote sits on the official page, so read it as the codec owner's summary of a 2015 study rather than an independent review. The same page publishes no latency figure at all, which shapes the measurement section below.
Bitrate and real-world behavior
| Codec | Cited rate | Depth / sample rate | Source / as of |
|---|---|---|---|
| aptX HD | 576 kbps | 24-bit, 48 kHz | aptX HD official page + SoundGuys comparison table, 2026-09-22 |
| Classic aptX | 352 kbps | 16-bit, 48 kHz | SoundGuys comparison table, 2026-09-22 |
| SBC | 320 kbps | 16-bit, 48 kHz | SoundGuys comparison table, 2026-09-22 |
There is no bitrate ladder here. aptX HD runs at a single design rate, and its only published flexibility is backward compatibility: a receiver without aptX HD negotiates classic aptX instead. That fallback matters for reading the numbers, because the anchored latency record belongs to classic aptX. The cross-codec rate view is our bitrate bench. Higher-rate codecs from other camps, such as Sony's LDAC, sit outside the aptX family entirely.
Measured latency
| Metric | Measured | Source / as of |
|---|---|---|
| Direct aptX HD average | No aptX HD average in the article text; the average-latency chart carries an aptX HD bar among seven codec bars | RTINGS dropped aptX HD at Test Bench 1.6, "replaced by aptX Adaptive (High Quality)"; SoundGuys text prints SBC, aptX, LDAC and AAC averages while its chart adds aptX HD. Accessed 2026-09-22 |
| Fallback chain: classic aptX | 316 ms average, 25.7 ms typical variance across four Android phones | SoundGuys (Bluetooth receiver + instrumentation rig, not headphones), published 2021-03, accessed 2026-09-22 |
| Consistency across aptX forms | "Most implementations of aptX (any form) should be reasonably consistent and predictable" | RTINGS latency research, accessed 2026-09-22 |
The absence is the datapoint. RTINGS retired aptX HD from its latency bench in favor of aptX Adaptive, and the SoundGuys Android program printed no aptX HD average in its text, though its seven-bar chart carries an aptX HD entry, so no text-anchored number exists for this page to archive. Anyone quoting an aptX HD latency figure is extrapolating from classic aptX, which measured 316 ms on that kind of rig. For film and gaming, the low-latency picks in our Bluetooth audio delay guide are the faster path. The cross-codec round-up is our latency bench.
Device and OS support
| Platform / device | aptX HD support | Source / as of |
|---|---|---|
| Android phones | Found across Qualcomm-powered models; Phones are a category in Qualcomm's aptX HD product directory | aptX HD official product directory, 2026-09-22 |
| iPhone / iPad | No; iPhones negotiate AAC and SBC only | SoundGuys codec support article, 2026-09-22 |
| Windows PCs | No native support; aptX HD is named among the codecs that need special drivers on Windows 11 | Microsoft Learn Q&A, 2026-09-22 |
| Transmitters and receivers | Receivers & Transmitters and Adapters are categories in the same official directory | aptX HD official product directory, 2026-09-22 |
| blafili XLR receiver | aptX HD listed in the product's own specifications | blafili product specifications, 2026-09-22 |
Pairing behavior
A link runs aptX HD only when both ends advertise it. The official backward-compatibility note means the usual fallback lands on classic aptX, and an iPhone source lands on AAC regardless of what the receiver supports. On Windows, aptX HD at all means third-party drivers, so most PC links stay on SBC. Per-model phone detail lives in our iPhone codec compatibility page.
FAQ
No lossless claim exists on Qualcomm's official page. The 576 kbps design rate sits below the 1.4 Mbps raw data rate of CD audio, so data reduction happens on every stream. Lossless transmission belongs to a separate codec in the aptX family, listed as its own entry in codec comparison tables.
No. iPhones negotiate AAC and SBC only, so an aptX HD-rated receiver or headphone falls back the moment the source is an iPhone. Our iPhone codec compatibility page has the per-model detail.
The official page publishes no latency figure, and the two measurement programs this page cites have no direct aptX HD number either: RTINGS replaced aptX HD with aptX Adaptive at Test Bench 1.6, and classic aptX measured 316 ms on the SoundGuys Android rig. For film and gaming, a low-latency chain is the faster path; our Bluetooth audio delay guide covers the options.
Both ends have to advertise the codec. The published fallback is classic aptX, which aptX HD is officially backwards compatible with. A Windows PC without third-party drivers cannot run aptX HD at all, and an iPhone source lands on AAC.
blafili B3 Bluetooth Receiver
XLR, RCA, optical and coax outputs with an OLED front panel, built on the QCC5125 + ES9018K2M platform. A wired amp or receiver, put on a wireless source.
- Qualcomm aptX HD official page: Bit Rate 576 Kbits (48 kHz sampling), Audio Encoding 24-bit up to 48 kHz, THD+N@1kHz -80dB, SNR@1kHz 129dB, PEAQ -0.05, backwards compatible with existing aptX products, Salford University 2015 blind test quote. aptx.com/aptx-hd, accessed 2026-09-22
- Qualcomm aptX HD product directory: category filters for Phones, Headphones, Receivers & Transmitters, Adapters, Speakers, Tablets, Laptops and more. aptx.com/product-listing?aptx_type=2, accessed 2026-09-22
- SoundGuys, Bluetooth codec support for headphones: comparison table (aptX HD 576kbps / 24-bit / 48kHz) and "iPhones only support the AAC and SBC Bluetooth codecs." soundguys.com/bluetooth-codec-support-headphones-61989/, accessed 2026-09-22
- SoundGuys, "Android's Bluetooth latency needs a serious overhaul": classic aptX 316 ms average and 25.7 ms typical variance across four Android phones; measured with a Bluetooth receiver and instrumentation, not headphones. soundguys.com/android-bluetooth-latency-22732/, accessed 2026-09-22
- RTINGS, "Test Bench 1.6: Latency R&D Article": Test Bench 1.6 dropped aptX HD, replaced by aptX Adaptive (High Quality); most aptX implementations of any form reasonably consistent and predictable. rtings.com/headphones/learn/research/latency, accessed 2026-09-22
- Microsoft Learn Q&A, Bluetooth codecs supported in Windows 11: aptX HD named among codecs not natively supported, requiring special drivers. learn.microsoft.com/en-us/answers/questions/5560825/, accessed 2026-09-22