[Roen]

I am prepared to be corrected but I did not think that was the case and I was of the view that the way BT AAC and APTX HD or LDAC work was different. My understanding is as follows:


AAC – Is re-encoded before being passed to headphones and then will of course be processed by the DAC in the headphones


LDAC/APTX-HD – Passed as-is to the headphones and the processed by the DAC


So for LDAC/APTX-HD a 328kbps Spotify file will be passed at it’s full bitrate as will the 500 kbps Opus file. FLAC is slightly more complex so not sure what would happen there?


So if the above is correct then on an iPhone anything above 256 kbps is a waste over BT whereas some android devices have way more headroom. On an iPhone though it does seem that Spotify or any other non- AAC service is compromised, maybe why a lot of reviews say that Apple music has the best audio quality??

Pretty sure all BT transmission codecs need PCM as an input, so there wouldn't be any passthrough unless a codec explicitly supports passthrough.

 

[Koolpep]

Pretty sure all BT transmission codecs need PCM as an input, so there wouldn't be any passthrough unless a codec explicitly supports passthrough.

Yes, that might be - but even then AAC is transparent - meaning you can decode and re-encode 100 times without significant quality loss.

 

[Roen]

Yes, that might be - but even then AAC is transparent - meaning you can decode and re-encode 100 times without significant quality loss.

Only if subsequent AAC encodes are at or greater than the bitrate of the original.

i.e. 256 -> 320 might be transparent, but 320 -> 256 could not logically be transparent.

 

[Koolpep]

Only if subsequent AAC encodes are at or greater than the bitrate of the original.

i.e. 256 -> 320 might be transparent, but 320 -> 256 could not logically be transparent.

Of course - I am talking about the same bitrate 256 to 256 you can do the test yourself - re-encode the same 256kbit/s file a couple of time sequentially - and listen. Or put it in a spectograph.

Cheers!

 

[Roen]

Of course - I am talking about the same bitrate 256 to 256 you can do the test yourself - re-encode the same 256kbit/s file a couple of time sequentially - and listen. Or put it in a spectograph.

Cheers!

This just makes me happier to use my 1000XM4 with my iOS over AAC.