HydrogenAudio

Lossless Audio Compression => FLAC => Topic started by: RichardFlack on 2018-11-06 05:57:57

Title: FLAC & iPhone
Post by: RichardFlack on 2018-11-06 05:57:57
I'm fairly new at this and I want to check that Im going about things in a reasonable manner.
Most of my "serious" music is in FLAC files on my hard drive (I use Logitech Squeezebox for streaming them in the house to NAD amp etc in basement).
I also have Apple Music for casual listening and of course all those tracks are "duplicated" there in lower quality form, which is fine for purpose (Kef ceiling speakers in kitchen, Energy bookshelf in living room old iphone with Harman Kardon CL phones etc).  

I now have an iPhone 8 plus with a lot more storage so I can put a good chunk my music library on it if I wish, and am looking at getting some mid-quality Bluetooth headphones.  So a ton of questions.

1.  Given its iPhone, I should get headphones that support AAC codec in the Blurtooth?  I realise aptX is no use, the question is am I right that AAC will be noticeable versus SBC.  Sennheiser (HD1, PXC550 etc) in particular seem not to support AAC.

2.  With mid quality headphones would I hear the difference between FLAC files transferred direct to the iPhone and played with, say, Foobar 2000 Mobile; versus convert to high bit rate AAC files before transfer to iPhone and then play through iOS Music App).  Or will that cause Apple to convert down to lower bit rate AAC?  Bear in mind I might also use the headphones wired in some cases, if it makes a difference, but Im not wild about the 2 cable thing with iPhone 8).   Im not entirely sure I understand what happens when Foobar2000 plays a FLAC file on the iPhone. 
Title: Re: FLAC & iPhone
Post by: magicgoose on 2018-11-06 08:10:21
1. Why aptX is no use? Yeah SBC will probably not be transparent, there are people who notice SBC distortion.

2. Source format should not cause any audible difference; it's certainly worth trying Opus by the way as it's the state of the art in lossy compression now. AAC won't have advantage because there's no such player that doesn't transcode for Bluetooth and that would make mixing impossible (stuff like other sounds/notifications, etc). But if you have heard about such players, then maybe it's worth testing if it will save some battery life by not transcoding for Bluetooth.

P.S. what is "mid quality headphones" is completely subjective so I'm not using that information in this answer
Title: Re: FLAC & iPhone
Post by: kode54 on 2018-11-06 08:51:38
1. Why aptX is no use? Yeah SBC will probably not be transparent, there are people who notice SBC distortion.
Being that he's talking about an iPhone, and no iOS products have ever supported aptX, that's why it will be no use to buy something that supports aptX. For iOS devices and Macs, you'd want something that supports AAC for listening, or possibly even that for two-way, or at least SBC.

2. Source format should not cause any audible difference; it's certainly worth trying Opus by the way as it's the state of the art in lossy compression now. AAC won't have advantage because there's no such player that doesn't transcode for Bluetooth and that would make mixing impossible (stuff like other sounds/notifications, etc). But if you have heard about such players, then maybe it's worth testing if it will save some battery life by not transcoding for Bluetooth.
That is correct. One should choose a reasonably transparent format for their device storage, and not rely on Bluetooth compression destroying the audio, rather, should have reasonable quality to start with so that it isn't degraded further.

P.S. what is "mid quality headphones" is completely subjective so I'm not using that information in this answer
Correct. It is completely subjective.
Title: Re: FLAC & iPhone
Post by: RichardFlack on 2018-11-06 16:02:20
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For iOS devices and Macs,
I believe at least some Macs DO support aptX (which makes not having it on iOS all the more Applesque  ;D )

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AAC won't have advantage because there's no such player that doesn't transcode for Bluetooth and that would make mixing impossible (stuff like other sounds/notifications, etc). But if you have heard about such players, then maybe it's worth testing if it will save some battery life by not transcoding for Bluetooth.
By "battery life" do you mean play time per charge or the lifetime of the battery?  Not too fussed by the former, within reason.  Of course the former affects the latter (more charges per month).
Id like to be clear, you are suggesting that Foobar would convert FLAC to AAC for broadcast?  I guess that's inevitable.  But I just subscribe to the concept of deferring down conversion as long or far as possible.  The only case for not doing that is if the conversion on desktop could be less lossy somehow than whats done on the phone, but I assume the algorithms are the same?

But you are ALSO saying  that it would also re-convert AAC (to AAC)?   Thats weird (to me anyway).

Mixing ... yeah that's something Id love to turn off, there is nothing more annoying that having the music interrupted, especially when Im using it as background music and then some advert or spam on a web page Im browsing hijacks the sound away from my music.


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Correct. It is completely subjective.
   Indeed.  Just like "mid priced wine" (or amplifier or ...).

On the headphone front the dilemma I have is that I like Sennheiser sound but they dont support AAC (HD1 and PCX 550), which I find rather odd.  Of the sets that do, none is perfect, either too expensive, dont fit too well, or the sound is way too bright, or too boomy.
The trick is probably not to over think it. 

Thanks for all the help.
Title: Re: FLAC & iPhone
Post by: magicgoose on 2018-11-06 22:53:33
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By "battery life" do you mean play time per charge or the lifetime of the battery?  Not too fussed by the former, within reason.  Of course the former affects the latter (more charges per month).
Id like to be clear, you are suggesting that Foobar would convert FLAC to AAC for broadcast?  I guess that's inevitable.
I mean the play time per charge.
It's unlikely that Foobar will do the conversion for broadcast, it's usually a job for a driver or some other OS component.

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But you are ALSO saying  that it would also re-convert AAC (to AAC)?   Thats weird (to me anyway).
Yes
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Mixing ... yeah that's something Id love to turn off, there is nothing more annoying that having the music interrupted, especially when Im using it as background music and then some advert or spam on a web page Im browsing hijacks the sound away from my music.
Need to specifically search for software which can do that.
No regular player can do this.
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On the headphone front the dilemma I have is that I like Sennheiser sound but they dont support AAC (HD1 and PCX 550), which I find rather odd.  Of the sets that do, none is perfect, either too expensive, dont fit too well, or the sound is way too bright, or too boomy.
The trick is probably not to overthink it. 
The trick is to use wired headphones and 3.5mm jack.
This is cheaper and has none of the problems that Bluetooth has.

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The only case for not doing that is if the conversion on desktop could be less lossy somehow than whats done on the phone, but I assume the algorithms are the same?
very hard to say, especially in closed source systems from Apple. you can probably sniff the protocol somehow to see which codec is being used, but even if the codec is the same, encoding method may be different. and it's not even a well defined problem to decide which is "less lossy". but if one can detect it by ear, then it must be bad.

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but they dont support AAC (HD1 and PCX 550), which I find rather odd
I'm pretty sure that AAC requires licensing fees as it's a format burdened by lots of patents, so this could be the reason.