iPhone AAC vs. Aptx and Aptx-hd real world
post-14567156
Post #286 of 304

bigshot

Headphoneus Supremus
Joined
Nov 16, 2004
Messages
21,221
Reaction score
3,386
Location
Hollywood USA
Joined
Nov 16, 2004
Location
Hollywood USA
Posts
21,221
Likes
3,386
Website
www.facebook.com
if your headphones are good enough you can easily hear the difference between file capped at 22khz and file capped at 19 Khz
Not likely. The difference between 19kHz and the upper limit of human hearing is a small fraction of a note on the musical scale. Most people over 30 can't even hear up to 19kHz. And it doesn't matter anyway, because recorded music doesn't generally have any audible content up there anyway.
 
     Share This Post       
  • Like
Reactions: pstickne
post-14567199
Post #287 of 304

Vin60

New Head-Fier
Joined
Oct 29, 2018
Messages
8
Reaction score
1
Location
Moscow
Joined
Oct 29, 2018
Location
Moscow
Posts
8
Likes
1
More importantly, one's ears need to be sensitive enough. Most adults can't hear 19KHz, and few humans at all can hear over 20KHz. (The difference between those frequencies, in terms of notes, is tiny.) None of it would be "easily heard".
You are absolutely right - I personally do not hear 20khz. However downsampling means not only the cap in khz, but degrading details as well, as otherwise it would be too simple.
 
     Share This Post       
post-14567230
Post #288 of 304

bigshot

Headphoneus Supremus
Joined
Nov 16, 2004
Messages
21,221
Reaction score
3,386
Location
Hollywood USA
Joined
Nov 16, 2004
Location
Hollywood USA
Posts
21,221
Likes
3,386
Website
www.facebook.com
Have you tested to find out what your threshold of transparency is for various codecs and data rates?
 
     Share This Post       
post-14567343
Post #289 of 304

Vin60

New Head-Fier
Joined
Oct 29, 2018
Messages
8
Reaction score
1
Location
Moscow
Joined
Oct 29, 2018
Location
Moscow
Posts
8
Likes
1
Have you tested to find out what your threshold of transparency is for various codecs and data rates?
Not sure I understand - Hz do not differ from data rates nor codecs. If you mean do I hear difference between Mp3 256 and Mp3 320? - some times yes, some times no, and I do not hear any difference between .flac and AAC 256
 
     Share This Post       
post-14567367
Post #290 of 304

bigshot

Headphoneus Supremus
Joined
Nov 16, 2004
Messages
21,221
Reaction score
3,386
Location
Hollywood USA
Joined
Nov 16, 2004
Location
Hollywood USA
Posts
21,221
Likes
3,386
Website
www.facebook.com
You mentioned that you heard degrading of details, I was just curious where your line of transparency was where there is no degradation any more.
 
     Share This Post       
post-14568241
Post #291 of 304

shortwavelistener

New Head-Fier
Joined
Jun 7, 2018
Messages
35
Reaction score
3
Location
Upstate Johor, Malaysia
Joined
Jun 7, 2018
Location
Upstate Johor, Malaysia
Posts
35
Likes
3
Interesting. I guess I usually use AirPlay and that would play AAC 256 as AAC 256.
Actually, that's because Airplay encodes the audio stream in ALAC (the same goes to it's predecessor, the Airport Express too). Since ALAC is a lossless format just like FLAC, so Airplay will retain all the information of the audio file, regardless of the type of audio file played from the source.
 
Last edited:
     Share This Post       
post-14568244
Post #292 of 304

bigshot

Headphoneus Supremus
Joined
Nov 16, 2004
Messages
21,221
Reaction score
3,386
Location
Hollywood USA
Joined
Nov 16, 2004
Location
Hollywood USA
Posts
21,221
Likes
3,386
Website
www.facebook.com
I didn't know that! Thanks!
 
     Share This Post       
  • Like
Reactions: pstickne
post-14568640
Post #293 of 304

Vin60

New Head-Fier
Joined
Oct 29, 2018
Messages
8
Reaction score
1
Location
Moscow
Joined
Oct 29, 2018
Location
Moscow
Posts
8
Likes
1
You mentioned that you heard degrading of details, I was just curious where your line of transparency was where there is no degradation any more.
Its really depends on content, but I’m sure everyone can hear difference between mp3 128 kbps and mp3 192 kbps. Keeping in mind android encodes in aac over bluetooth in less then 128 kbps mp3 quality (I presume its 96kbps) android users should definitely stick to aptx or its higher equivalents
 
     Share This Post       
  • Like
Reactions: pstickne
post-14568787
Post #294 of 304

AKGForever

New Head-Fier
Joined
Oct 26, 2018
Messages
20
Reaction score
5
Location
New Jersey
Joined
Oct 26, 2018
Location
New Jersey
Posts
20
Likes
5
Mastered for iTunes means that the source is a studio quality master (i.e.: 24/96), and the encoding is customized to make it as efficient and high quality as possible. But the end result is still AAC 256 VBR. That isn't a bad thing though, because AAC 256 VBR is audibly transparent. With human ears, you won't be able to discern it from the master.
What does "Mastered for iTunes " mean when the source was originally recorded in analog? Unfortunately I found nothing in the Apple description saying that the source has to be from original source material. CDs and AAC made from sources made in the 1960s through the 1980s are all over the place quality wise. Some of it is poor recording techniques but a lot of it is because the masters are multi-generational. I also find that compilations, especially those from various artist, tend to be of poorer quality and from a mult-generational source.
 
Last edited:
     Share This Post       
post-14569013
Post #295 of 304

bigshot

Headphoneus Supremus
Joined
Nov 16, 2004
Messages
21,221
Reaction score
3,386
Location
Hollywood USA
Joined
Nov 16, 2004
Location
Hollywood USA
Posts
21,221
Likes
3,386
Website
www.facebook.com
All content distributors are at the mercy of what master the label pulls off the shelf. And "best ofs" and compilations are going to tend to be a hodgepodge of sources.
 
Last edited:
     Share This Post       
post-15000483
Post #296 of 304

pstickne

100+ Head-Fier
Joined
May 25, 2019
Messages
335
Reaction score
176
Location
Portland, OR (USA)
Joined
May 25, 2019
Location
Portland, OR (USA)
Posts
335
Likes
176
I found https://www.soundguys.com/understanding-bluetooth-codecs-15352/ interesting. Some points:
- Bluetooth AAC is highly dependent on the specific encoding stack's implementation (and pre-encoded AAC do not appear to be sent "as they are"). It is effectively only [almost] "CD quality" on iPhone devices. Naturally, it will never have more information that the original source.
- Bluetooth AAC is psychoacoustic whereas aptX is not - so AAC is more akin to an inline 'conversion to MP3' (offending anyone a bit? :D). This is also why AAC requires more power/processing than SBC/aptX and why comparing 'Bluetooth transmission bitrates' between different protocol can be misleading.
 
Last edited:
     Share This Post       
post-15000500
Post #297 of 304

pstickne

100+ Head-Fier
Joined
May 25, 2019
Messages
335
Reaction score
176
Location
Portland, OR (USA)
Joined
May 25, 2019
Location
Portland, OR (USA)
Posts
335
Likes
176
..aptX HD, LDAC, DSD, MQA etc. are gimmicks..
It's a shame really, as the DSD encoding was designed as an alternative/improvement to PCM encoding. Excluding licensing opportunities and the like, one reason was to make hardware simpler and cheaper. (And there isn't anything wrong with that goal.)

It's the re-introduction as a "Hi-Fi" badge as opposed to data representation format that is the gimmicky bit - higher numbers is better? I guess one can always covert CD (eg. "a" PCM encoded source) to DSD and call it a day.. same data, different pattern of bits.
 
Last edited:
     Share This Post       
post-15018336
Post #299 of 304

pstickne

100+ Head-Fier
Joined
May 25, 2019
Messages
335
Reaction score
176
Location
Portland, OR (USA)
Joined
May 25, 2019
Location
Portland, OR (USA)
Posts
335
Likes
176
ios only support aac and aac and aptx has a huge differncen since aptx can send 16/44.1
Uhh, AAC “can send” 16/44 as well. However, such statements add little to no value as discussed in https://en.wikipedia.org/wiki/Audio_bit_depth Remember that both AAC and aptX are lossy and neither is PCM; one has to look at the quality of the resulting decoded (PCM, DSD, whatever) signal**.

Also, AAC is arguably a more transmission-efficient codec (for human consumed audio) as it utilizes stronger psychoacoustic principals so even looking at BT wire bandwidth usage can be very misleading.

**As noted previously, there is a wide range of differences in the quality of AAC encoders, with many Android implementations being subpar.
 
Last edited:
     Share This Post       
  • Like
Reactions: 435279
post-15019830
Post #300 of 304

castleofargh

Sound Science Forum Moderator
Joined
Jul 2, 2011
Messages
8,955
Reaction score
4,294
Joined
Jul 2, 2011
Posts
8,955
Likes
4,294
https://habr.com/en/post/456182/

I don't know enough to say if everything in this article is correct, but the little I know seemed to align.
it certainly is very informative.
 
     Share This Post       
  • Like
Reactions: pstickne

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top