Bluetooth to Unitiqute2 Apt-x vs AAC
Posted by: Nic-collins on 06 January 2017
I stream Tidal (Hi Fi) to my Unitiqute2 via Bluetooth to get round dropouts experienced with the Naim Tidal app. When I stream from an Ipad the Unitiqute2 shows AAC on the track display but if I stream from my Samsung S6 it shows Apt-x and sounds much better. Am I correct in thinking that AAC from an iPad compresses the HiFi stream from Tidal much more than Apt -x from an Android device?
I read somewhere that apple does not support aptx so then only use standard bluetooth connection. So I think you're right since it's only using low quality bluetooth connection which is not aac afaik.
Apple wants you to use Airplay for higher quality. Sometimes I'm surprised they even implemented Bluetooth.
Ah yes, the iPad Mini 4 only uses Bluetooth 4.2 so my elderly ears were quite correct when they noticed a big difference when streaming from my android phone! Once again Apple shoot themselves in the foot!
This has nothing to do with the Bluetooth version. BTW, BT 4.2 is the current version, so it is quite appropriate that the iPad only uses it.
For some reason, Apple only supports the apx-X codec in mac OS (along with AAC and the BT-mandatory SBC codec), but only AAC and SBC in iOS. And even then, you have to use a (registered developer only) tool to enable it in macOS.
The AAC codec in iOS uses an audio bitrate of 256 kB/s (+ some header data). Basically, this is the same quality as in the iTunes Store / Apple Music (PDF below, Page 16).
https://developer.apple.com/ha...DesignGuidelines.pdf
The apt-X Standard codec does indeed sport a bitrate which is a bit higher (350something kB/s gross data rate, I don't remember what the net audio data rate is), but the difference is not as big as to support a massive improvement in sound quality over 256 kB/s AAC. But there are apt-X variants (Enhanced, Lossless – which even supports HD audio) which use much higher data rates.
Is there some information on the Naim what exact apt-X codec is used (Standard, Enhanced, Lossless etc.), the data rate etc.?
I'm guessing the Apt -x codec is lossless because listening to Tidal Hi Fi streamed from my Samsung S6 sounds the same as all my other WAV and FLAC files streamed from my NAS, whereas Tidal streamed from the iPad sounds like average MP3.
According to the tech specs, it it not lossless (spec says aptX "Classic" which I translate to bog-standard aptX).
So the question still is, why does the apt-X codec sound so much better than AAC, because standard aptX and AAC are more or less the same, quality-wise (same sample rate, similar compression ratio etc.).
The thing is, I have an Arcam BT receiver connected to my (non-BT) 172 XS and there is no discernible quality difference between apt-X and AAC codecs. On the other hand, Naim recently has a mediocre (at best) track record in terms of software implementation, so I would not be surprised If they botched something up here.
Did you check the Tidal iOS app's audio quality settings?
Oh yes it's set to Hi Fi, it would appear that the Apt X codec allows much higher quality streaming even though it may not be 'lossless'. Of course I'd be much happier if the Unitiqute2 could manage to stream Tidal without dropouts using its built in app :-(