With the rise of Hi-Res music, wireless transmission systems and technologies are constantly evolving to accommodate ever increasing data rates. After Bluetooth aptX and aptX HD, LDAC and the recent HWA and LHDC, a new even more revolutionary codec has just dropped: SCL6 or MQair. Developed by MQA, it enables wireless transmission of MQA tracks and PCM streams at up to 24-bit/384kHz, with data rates up to 20 Mbps. The promise of wireless, lossless sound?
What is SCL6?
SCL6 is the sixth generation of the scalable codec developed by MQA. Recently certified Hi-Res Audio Wireless by the Japan Audio Society (JAS), this new codec will be launched very soon under the name of MQair. It aims to improve wireless audio quality in Bluetooth, UWB (Ultra Wide Band) and WiFi. Scalability is one of the major arguments of this codec. It can automatically adapt the quality of the link depending on the transmitting and receiving devices or the connection. Its speed can vary from 200 kbps (lossy) to 20 Mbps (lossless). This allows the transmission of Hi-Res files up to a very high resolution of 24-bit/384kHz for PCM streams, but also to stream MQA files. A first!
Thanks to its high data rate, the SCL6 format promises to outperform all other codecs. By comparison, aptX Lossless works from 140 kbps to 1 Mbps and can transmit streams up to 16-bit/48kHz. Bluetooth LDAC has a variable data rate on three levels: 330 kbps, 660 kbps and 990 kbps. It can process audio signals up to 24-bit/96kHz. Far from the 24-bit/384kHz offered by SCL6.
| aptX HD | aptX Lossless | LDAC | SCL6 (MQair) | |
| Minimum data rate | 330 kbps | 140 kbps | 330 kbps | 200 kbps |
| Maximum data rate | 576 kbps | 1 Mbps | 990 kbps | 20 Mbps |
| Maximum resolution | 24-bit/48kHz | 16-bit/48kHz | 24-bit/96kHz | 24-bit/384kHz and MQA |
How does the SCL6 codec improve the listening experience?
In addition to its very high scalability, the SCL6 codec also stands out from other formats because of its ability to influence the timing of the signal. According to MQA, this criterion is an essential element in our perception of high resolution sound. Bob Stuart, founder and CTO of MQA, says, “High resolution is shaped by small elements that convey detail, separation, and the feeling of space. By focusing on the temporal aspect of the signal, the SCL6 format should provide better sound quality, with less artifacts than with current codecs.
How to take advantage of SCL6 (MQair) transmission?
The SCL6 codec will soon be offered to users under the more attractive name of MQair. Thanks to its seamlessly scalable data rate, it will be able to work with Bluetooth transmission, but also with WiFi and Ultra-Wideband (UWB) connections. To enjoy it, it will be necessary to have a source such as a smartphone, a tablet, a computer or a DAP and a receiver such as wireless headphones or an amplifier compatible with the codec. The good news is that this compatibility can be obtained by a simple update on some equipment. The SCL6 format has no hardware requirements. The only condition is that both devices (source and receiver) have a Bluetooth controller powerful enough to process the signals.
SCL6 wireless transmission looks very promising for enjoying true high-fidelity sound with Bluetooth headphones, True Wireless earbuds and connected speakers. This new technology is expected to appear quickly during the year on the latest generation of wireless equipment and devices compatible with the MQair update.
