Hi All,
Who here has had any firsthand experience comparing Bluetooth Codecs???
I suppose this belongs in the headphones section as Bluetooth mainly impacts mobile headphone users.
For various reasons I have been exploring the Use of Bluetooth connectivity in an Audio context. I know it is not a perfect solution but we as consumers of high-quality music would be wise not to ignore it else it be at our own peril, if not for all our listening but at least our mobile, “on the go” listening habits. I also happen to have a collection of Bluetooth audio receivers. This allows me to connect to my home gear and stream music from a Phone or Tablet. FM reception is very poor in this area so steaming my favourite FM stations is the only option. Also, I now get to listen to BBC3 In Australia, streamed all the way from the UK.
In my current setup I have made some preliminary comparisons with SBC (the default codec) AAC and aptX over a Bluetooth connection. A quick look online would suggest that AAC should be better than SBC, however under Bluetooth AAC has been cobbled at 256kbps (320kbps over a wired connection is its absolute maximum bit rate) where SBC is 328kbps with a strong signal. While AAC is theoretically a better codec, SINAD measurement with AAC codecs show a wide side band either side of the test signal that is quite visible above the noise floor. The aptX and aptXLL codec offers 352 kbps but this codec still displays the wide side band either side of the test signal. On the positive side, the aptX codec does demonstrate lower Audio Latency while aptxLL offers even better Latency, typically around 40ms rather than 200-300ms for SBC.
To my ears I honestly cannot tell the sonic difference between SBC, AAC, and aptX with the exception of aptXLL and this was only the low latency that gave it the advantage, I could not discern any real audio quality difference.
Sony has introduced LDAC that promises higher bit rates up to 990kbps but at the moment this codec is propriety to Sony and its usage amongst non-Sony hardware is very limited, probably due heavy licensing fees and complex licensing agreements. Therefore; at the moment for most applications LDAC is not yet an option on generally available hardware. LDAC also seems very sensitive to Bluetooth signal quality. Some reviewers have commented that the headphones will drop back to SBC as soon as the phone goes into the user’s back pocket. Interestingly though; LDAC’s audio latency is up around 900ms.
I suppose my conclusion is, with the exception of LDAC, that there is no real improvement of overall sound quality. On face value AAC appears to offer better quality compression for a given bitrate but falls short on only offering 256kbps over a Bluetooth connection, it also displays higher levels of IM distortion. aptX gives us back our bitrate but also displays IM artifacts. LDAC offers better sound quality but is not widely supported and soon drops back to lower bit-rates (or even defaults back to SBC) when the connection signal becomes mildly compromised.
I would be interested to hear any comments or experiences.
LPSpinner
Who here has had any firsthand experience comparing Bluetooth Codecs???
I suppose this belongs in the headphones section as Bluetooth mainly impacts mobile headphone users.
For various reasons I have been exploring the Use of Bluetooth connectivity in an Audio context. I know it is not a perfect solution but we as consumers of high-quality music would be wise not to ignore it else it be at our own peril, if not for all our listening but at least our mobile, “on the go” listening habits. I also happen to have a collection of Bluetooth audio receivers. This allows me to connect to my home gear and stream music from a Phone or Tablet. FM reception is very poor in this area so steaming my favourite FM stations is the only option. Also, I now get to listen to BBC3 In Australia, streamed all the way from the UK.
In my current setup I have made some preliminary comparisons with SBC (the default codec) AAC and aptX over a Bluetooth connection. A quick look online would suggest that AAC should be better than SBC, however under Bluetooth AAC has been cobbled at 256kbps (320kbps over a wired connection is its absolute maximum bit rate) where SBC is 328kbps with a strong signal. While AAC is theoretically a better codec, SINAD measurement with AAC codecs show a wide side band either side of the test signal that is quite visible above the noise floor. The aptX and aptXLL codec offers 352 kbps but this codec still displays the wide side band either side of the test signal. On the positive side, the aptX codec does demonstrate lower Audio Latency while aptxLL offers even better Latency, typically around 40ms rather than 200-300ms for SBC.
To my ears I honestly cannot tell the sonic difference between SBC, AAC, and aptX with the exception of aptXLL and this was only the low latency that gave it the advantage, I could not discern any real audio quality difference.
Sony has introduced LDAC that promises higher bit rates up to 990kbps but at the moment this codec is propriety to Sony and its usage amongst non-Sony hardware is very limited, probably due heavy licensing fees and complex licensing agreements. Therefore; at the moment for most applications LDAC is not yet an option on generally available hardware. LDAC also seems very sensitive to Bluetooth signal quality. Some reviewers have commented that the headphones will drop back to SBC as soon as the phone goes into the user’s back pocket. Interestingly though; LDAC’s audio latency is up around 900ms.
I suppose my conclusion is, with the exception of LDAC, that there is no real improvement of overall sound quality. On face value AAC appears to offer better quality compression for a given bitrate but falls short on only offering 256kbps over a Bluetooth connection, it also displays higher levels of IM distortion. aptX gives us back our bitrate but also displays IM artifacts. LDAC offers better sound quality but is not widely supported and soon drops back to lower bit-rates (or even defaults back to SBC) when the connection signal becomes mildly compromised.
I would be interested to hear any comments or experiences.
LPSpinner
