Enhancing Bluetooth Music Quality: Q&A on Audio Encoding
With the continuous advancement of transmission technology, Bluetooth music playback has gradually moved from a supporting role to the forefront, and its sound quality has slowly been accepted by discerning audio enthusiasts, becoming an option among audio system sources. Many audio products priced at tens of thousands of dollars now integrate Bluetooth music playback functionality. In this issue, we have selected 10 products with Bluetooth music receiving capabilities to share with everyone. These 10 products all use the most advanced Bluetooth receiving modules currently available, supporting industry-trusted transmission protocols such as AptX-HD or LDAC, along with careful tuning by manufacturers, making it possible for Bluetooth music to achieve Hi-Fi quality.Bluetooth Audio Encoding Technology Q&A
> What Bluetooth audio encoding technologies are available?Currently, Bluetooth audio encoding technologies include SBC, AAC, aptX, aptX LL, aptX-HD, LDAC, and LHDC. Among these, SBC is the most common encoding and is a mandatory requirement for all Bluetooth devices. AAC is a high-compression audio encoding, commonly used at a bitrate of 256Kbps in Bluetooth, with Apple being its biggest supporter. aptX is an encoding developed by Qualcomm that can transmit audio close to CD quality. aptX LL can be considered a low-latency version of aptX, allowing Bluetooth transmission audio to be highly synchronized with the images you see. aptX-HD is a superior encoding to aptX, capable of transmitting lossless or even high-definition audio. LDAC is an encoding developed by SONY that, like aptX-HD, can transmit lossless or even high-definition audio. LHDC is similar to SONY’s LDAC, both certified by the Japan Audio Society’s Hi-Res Audio Wireless Bluetooth high-quality standard.Among these encodings, aptX-HD, LDAC, and LHDC are the most excellent, followed by aptX, with SBC and AAC trailing behind. In other words, aptX-HD, LDAC, and LHDC offer the best sound quality, aptX is slightly better, while SBC and AAC are quite average.> Do Bluetooth devices that support aptX-HD, LDAC, and LHDC encoding guarantee good sound quality?Overall, supporting the above encodings is one of the conditions for good sound quality. Additionally, it depends on the manufacturer’s design, hardware configuration, and tuning.> Can I use my phone with Bluetooth devices to play high-definition music?The aptX-HD, LDAC, and LHDC encodings provide the foundation for transmitting high-definition music. In theory, a phone that supports aptX-HD, LDAC, and LHDC in conjunction with compatible Bluetooth devices can be used to play high-definition music. However, in practice, most phones are limited by the system, and even if they support the above encodings, they cannot fully present high-definition music; they can play it, but the transmission is not truly high-definition. However, lossless music is still possible, and the LDAC encoding, which is limited by the system, can even transmit 24bit/44.1kHz. Therefore, whether it is high-definition music should not be overly concerned about; otherwise, the author suggests you might as well enjoy digital playback. For Apple phones that do not support the above encodings, playing high-definition Bluetooth music is even more impossible.Purchase Recommendations for Bluetooth Receiving Devices> First, confirm the Bluetooth encoding supported by your mobile deviceOnce, a friend bought a Bluetooth receiver that supported aptX-HD and LDAC encoding, but his phone did not support these encodings and could only play music using SBC encoding, completely unable to experience the joy of lossless music. Therefore, before purchasing related Bluetooth audio receiving devices, ensure that your phone or tablet supports the relevant encodings to avoid confusion, unless you find the sound quality of SBC encoding acceptable.> Next, check the encoding supported by the Bluetooth audio receiving deviceUndoubtedly, among all encodings currently available, aptX-HD, LDAC, and LHDC are the most excellent. However, aptX-HD and LDAC are the more popular encodings, and good Bluetooth receiving devices can support both (or one of them). As long as the phone or tablet is not too outdated, it should support these two encodings. LHDC is relatively niche, so it is recommended not to prioritize it. Therefore, it is suggested to first choose Bluetooth receiving devices that support aptX-HD and LDAC encoding.> It is advisable to choose products with independent decodingCurrently, many Bluetooth Hi-Fi audio receiving devices use Qualcomm’s CSR8675 flagship Bluetooth chip, which integrates audio decoding functionality (similar to a computer’s integrated graphics), allowing for analog signal output without needing an external decoder. However, integrated decoding is always inferior to independent decoding. To enhance sound performance, many manufacturers reserve certain functionalities when using CSR8675, either by changing parameters through settings or bypassing the internal decoder in favor of an independent decoder.> Digital output is preferableMany Bluetooth Hi-Fi audio receiving devices are compact and may not achieve perfection, leading to deficiencies in power supply and configuration, which may result in inadequate quality of analog output. Therefore, many manufacturers provide digital output on their devices, allowing users to connect external decoders to enhance sound performance. Thus, when purchasing, it is best to choose products with digital output.> Finally, testing and listeningOf course, testing involves connection performance, such as connection speed and distance, and whether there are frequent stutters or unexplained disconnections during playback. If everything is normal, then careful listening can proceed.For those who have not listened to devices supporting aptX-HD, LDAC, and LHDC encoding, the first listening experience may bring new sensations. Overall, Bluetooth receiving devices that support the above encodings have significantly improved sound smoothness and texture. If you hear a smooth and natural sound with a sheen, it indicates that the product possesses a certain quality and is worth having.For those with high demands, if conditions allow, further comparisons with other audio sources, such as CD players and digital players, can be made. However, it should be noted that the better the performance and the higher the configuration of Bluetooth music devices, the higher the price will be. Whether it is worth purchasing depends on your needs and affordability.
