Apple Reportedly Developing High-Definition Audio Format with 'Adaptive Streaming'

[petsounds]

The only catch being AirPlay will down sample ALAC to 16bit/44khz - but hopefully this will change when / if they introduce this.

John Atkinson of Stereophile magazine tested the Airport Express and found the digital output of a 24-bit file was bit-for-bit the same. (The article isn't archived on their site unfortunately, but those guys generally know their stuff)

This was surprising to me also, because I thought the chip in the aging Airport Express only handled 16/44.1, unless they've silently replaced it. Regardless, if there is a downsampling occurring, I believe it is not via AirPlay itself. I do wish Apple would introduce an audiophile version of the Airport Express with a better D/A chip. Perhaps with this new format…

 

[.Locke]

How did you read "Apple developing an HD audio format" into the actual news "Apple developing a new audio format with 'adaptive streaming'"?



No one claiming stuff like this ever passed a blind-test, no one ever could even tell 256kb/s AAC files and a CD apart. Frequencies you don't hear don't alter the perception of frequencies you hear, that's audiophile mumbo-jambo.

*edit* Also, even higher or lower frequencies are probably not even recorded by a standard studio microphone in the first place, because recording equipment is based on scientific knowledge about acoustics as well.

Trust me when I tell you these are not audiophile mumbo-jambo!!
If you have speakers >1000€ / pair and a descent amp to drive them, then the difference between 256kb/s AAC and a CD is audible. The more expensive your equipment, the more obvious the difference! If however you use a crapy pair of buds to listen on the go, you probably couldn't tell the difference...
With SACD and DVD-Audio however, it's a different thing! If you hear those formats on a good rig, with a proper setup, on a properly treated room, you will never go back to CD!! (of course I still have some cd's that I cannot find in other formats)
The recordings for those formats are made with microphones that can record up to 96khz (at 192khz sampling) or in some cases even higher! (for other formats - mostly archival at the moment)
One of the key differences between a digital and an analog format is that when you record in analog you have infinite samples! You are recording every pSec of what you perceive as reality. In a digital recording you have a specific amount of samples/sec (hz) which, in the case of a CD, are not enough to capture the whole musical reality!

Here is a link you may find interesting
http://www.cco.caltech.edu/~boyk/spectra/spectra.htm

 

[mijail]

One of the key differences between a digital and an analog format is that when you record in analog you have infinite samples!

Absurdly wrong. (yeah, here we go again against the Analog Myth)
Just tell me, where are you storing those infinite samples? In some magical finite medium?

 

[gnasher729]

Although I'm a long time Apple user I really am distressed Apple is not supporting FLAC. Basically they want to control music sales. FLACs are open.

Well, ALAC is open. And anyone can write a Quicktime plugin to support FLAC, and then publish it widely. Just nobody has done so yet. And then there is the question whether there are any patents covering FLAC. As long as nobody with deep pockets (like Apple) supports it, we won't know.

So now we ll have to buy again from the AAC compressed crap they VE been selling so far?

Most people don't. But Apple observes these boards, and if they find anyone posting questions like that, all the AAC files on their computer will stop working, and they have to buy again. Everyone else, they just re-download everything from iTunes Match.

Theoretically, what's better: If "Mastered for iTunes" files for us to buy on iTunes will be 24bit/96kHz but lossy VERSUS Apple Lossless (from a CD) that's 16bit/44kHz and lossless? Apple Lossless (ALAC) would sound like a CD. "Mastered for iTunes" has a better bit depth of 24 bit and a better sample rate of 96kHz than a CD, but "Mastered for iTunes" is lossy.

Theoretically, it could go either way. The biggest difference is in the original source. If you bought a CD that was created from some second class master, and then the company digs out a better master and submits it to the iTunes store, then the AAC version may very well be better. If they start with 24bit/96KHz, then create a CD from it _and_ submit the 24bit/96KHz to iTunes, then the CD will very likely be better. The important thing is that 24bit -> AAC is better than 24bit -> CD -> AAC, so "Mastered for iTunes" should always be better than your CD ripped to AAC in iTunes.

 

[.Locke]

Absurdly wrong. (yeah, here we go again against the Analog Myth)
Just tell me, where are you storing those infinite samples? In some magical finite medium?

What I wanted to point out is that when you make an analog recording you do not take samples.
Let's say that you are writing on a vinyl a violin playing. The head touches down at the beginning of the recording and is released at the end. During the hole time the head is in touch with the vinyl plate and is recording the sounds coming from the violin. The CD takes samples 44100 times a sec. In comparison, the head (in the above example) would be touching down and releasing from the vinyl plate 44100 times a sec. In other words you would lose information!
All I'm trying to point out is that a sample of 44.1khz is not enough. A higher sample rate not only gives you the ability to record higher frequencies and harmonics, but also captures MORE of the actual music event. That's why DVD-Audio stores files at 24bit/96khz and SACD at 1bit/2.8Mhz
Is it an audible difference? YES... IF you have a proper setup with good equipment...

 

[Diode]

John Atkinson of Stereophile magazine tested the Airport Express and found the digital output of a 24-bit file was bit-for-bit the same. (The article isn't archived on their site unfortunately, but those guys generally know their stuff)

This was surprising to me also, because I thought the chip in the aging Airport Express only handled 16/44.1, unless they've silently replaced it. Regardless, if there is a downsampling occurring, I believe it is not via AirPlay itself. I do wish Apple would introduce an audiophile version of the Airport Express with a better D/A chip. Perhaps with this new format…

You are correct - Airplay is not limited to 16/44.1 as a protocol (for those that don't know AirPlay is simply a Apple-lossless stream) but it seems to be a limitation now. Speculation is it's either hardcoded in iTunes or via the Midi sound app (Where you set your sampling output etc).

You can trick the AE through command lines to output 24bit but all you get is noise at the moment. The AE should be able to pass on 24/192 files as it's just passing through the stream and letting an external DAC handle the file - it would only be a problem if you were using analog output because it would be using it's own DAC.

There's a good thread going on at the Apple forums discussing this limitation.

----------

Theoretically, what's better: If "Mastered for iTunes" files for us to buy on iTunes will be 24bit/96kHz but lossy VERSUS Apple Lossless (from a CD) that's 16bit/44kHz and lossless? Apple Lossless (ALAC) would sound like a CD. "Mastered for iTunes" has a better bit depth of 24 bit and a better sample rate of 96kHz than a CD, but "Mastered for iTunes" is lossy.

Ideally, the best would be 24/96 and lossless, which I believe is the same as the studio digital master, correct?

BTW, if Apple were to offer in the future 24/96 lossless, would that, could that also be called Apple Lossless (ALAC)? Or would another name for the format be needed? Can I now rip a SACD that's 24bit/96kHz into ALAC format into iTunes?

Thanks!

The current implementation of "Mastered for iTunes" has studios encoding the songs for iTunes from the source - IE the original studio recording (or master). It is still a lossy format so it would not be a bit for bit copy of the original.

A ALAC copy from a CD (or Vinyl rip) will still be a better sounding file if the CD is off good quality (Which is not always the case).

However, if speculation holds true and Apple begins providing lossless files mastered from the source, then they will sound much better then CD's sound currently.

While SCAD ripping is *possible* it's left for other forums....

 

[rhett7660]

Although I'm a long time Apple user I really am distressed Apple is not supporting FLAC. Basically they want to control music sales. FLACs are open.

It would be a terrible shame if the computer business ever standardized on a closed source like Apple's. Fewer machines would be capable of playback.

Archive.org allows free downloads of legal music. Some of it is great. Anyone who likes the Grateful Dead should visit. Trent Reznor put his entire Ghosts I-IV album on archive at 24bit 96khz for anyone to download free of charge. How cool is that.

I'm also going to put in a plug for a talent worthy of more recognition:

http://www.archive.org/details/Transcendissonance

----------



I used to think that too. I once had 20,000 records. But you know moving those beasts around... well you know.

I really think that 24bit files will change your attitude someday. Trust me they sound so damn good you won't believe it. I personally can't hear past 24bit 48khz. Some people say they can. But like I mentioned in the previous, Trent Reznors Ghosts I-IV is available at 24/96 right now, free AND legal:

http://www.archive.org/details/NineInchNailsGhostsI-Ivblu-ray24bit96khz

Try it out on your computer using headphones. This is the future for audiophiles IMHO. We are a small portion of the listening public, perhaps 5% or less. Most people are fine with mp3. They listen for different things.

Thanks for the info,,,,,,, I knew he was doing MP3, didn't know about the high rez versions.....

 

[milo]

Harmonics anyone?
Instruments produce musical information well beyond 15khz! (some instruments beyond 100khz as a matter of fact!!) The frequencies beyond 15khz affect the frequencies we hear, thus altering the musical perception of an instrument! That's why a violin, when reproduced from a CD, will never sound like the real thing... With DVD-Audio and SACD thought it's a different story.

Of course instruments produce frequencies over 20k, nobody has said otherwise. People just can't hear those frequencies. Or are you talking about how higher frequencies can change audible frequencies - in that case the interaction happens before the sounds get to the mic so it still doesn't matter that the inaudible frequencies aren't recorded.

And NO recording of a violin will sound exactly like the original instrument, but that's a limitation of the mics and speakers as much as any recording medium.

Standard physics. If you understand that all sound waves have the capability of interacting with each other you'll understand. All sound is air pressure variations on the ear.

Think two strobe lights blinking at different rates.

All surfers know this phenomenon. They evaluate waves. They call them "sets." Surfers know that waves coming from two different directions cause some waves to be bigger and some to be smaller. Depending on the periodicity of the two sets of waves sets can come every few minutes to 20 minutes or more. Surfers try to catch the larger waves of the sets generally and wait out the smaller waves.

"Standard physics"? Your post is completely irrelevant. Nobody disputes that higher frequencies EXIST. The point is that people can't hear those higher frequencies, and nothing you said has anything to do with that.

You are not seeing the FULL picture.

http://www.stereophile.com/features/308mp3cd/index.html

That article has a bunch of analysis of frequencies and tones and waveforms but doesn't mention a single listening test. Lossy audio isn't the exact audio as the uncompressed version, nobody has ever disputed that. The point is that the differences are supposed to be inaudible to the human ear. Whether that is the case is determined by blind listening tests.


Speaking of, as part of their new tools Apple has a plugin that includes an ABX blind listening test feature. Runs as an AU plugin, anyone who has Garageband or any other audio app can do the comparison. Anyone claiming they can hear various differences, I'd encourage you to download it and actually test yourself. Plenty of people are convinced they can hear a difference but fail when doing an actual blind comparison.

http://www.apple.com/itunes/mastered-for-itunes/

 

[mijail]

During the hole time the head is in touch with the vinyl plate and is recording the sounds coming from the violin.

No.

The needle and the arm supporting it have a mass, which has to be moved by the vinyl grooves. But mass on movement has inertia. If you have a big change in the surface of the vinyl, the needle won't be able to track the change. It will jump over a big pit, for example, so you'll have an unknown, uncontrolled period of silence until the needle lands - which further produces an unknown, uncontrolled signal peak.
That's about the big details (a big signal peak followed by small signal). And about small details, the vinyl has a "resolution": the granularity of the vinyl, or the smallest pit that you can actually press on it. Extreme example: you can't engrave a detail smaller than a vinyl molecule.

And that's not even taking into account the need of the vinyl to be in virgin state (so every pit is where it is supposed to be, without any deformation or even wearing out). Nor the need for the turntable being perfectly stable and horizontal and isolated from movement (typically, floor vibrations can be felt in the audio anyway). Nor the need for the needle and arm to be perfectly stabilized as well. And that pesky static electricity and the dust! And those greasy fingerprints!

So, to summarize: vinyl = too many things uncontrolled. If you are thinking you have a perfect reproduction, you are kidding youself. A lot.

If would be less bad if you tried with laserdiscs, which were also analog, but didn't have the needle/arm problem.

The CD takes samples 44100 times a sec. In comparison, the head (in the above example) would be touching down and releasing from the vinyl plate 44100 times a sec. In other words you would lose information!

A digital recording defines exactly what it records - and what it doesn't. You want more information recorded? you only need to push up the specs.

The point is, you always lose information. With analog, it's difficult to know exactly how much you lose. But with digital recording, you at least get to define exactly which part of the information you want to keep.

And as a bonus, you can then reproduce and process that information with less problems.

All I'm trying to point out is that a sample of 44.1khz is not enough. A higher sample rate not only gives you the ability to record higher frequencies and harmonics, but also captures MORE of the actual music event. That's why DVD-Audio stores files at 24bit/96khz and SACD at 1bit/2.8Mhz
Is it an audible difference? YES... IF you have a proper setup with good equipment...

So, push for those better specs, of course.
But going analog doesn't help at all.

 

[Otto J]

LOL what. Hate to burst your monopolistic bubble, but AAC is an open standard. I'm not even sure that Apple was part of the original standards group. And guess what, even your evil Flash Player can play AAC files too.

Open standards are good things. If Apple developed a truly-closed music format, you'd only be able to play them on (some) Apple products. Maybe that's all you care about, but compatibility with other services and products is important for most people.

You're right, I put that wrong: I would prefer a good, but closed standard over a poor, but open standard. Obviously good AND open is #1, and I do believe that Apple agree. I don't want standards to be closed as such, but I do want them to actually be STANDARDS, as in not including several different ways of doing stuff.

 

[dashiel]

You are entitled to your own opinion I suppose, but it just happens to be wrong. Apple's worst product ever!

As the “proud” owner of a PowerBook 5300ce I can categorically state the earbuds are not even close to being Apple’s worst product.

 

[.Locke]

No.

The needle and the arm supporting it have a mass, which has to be moved by the vinyl grooves. But mass on movement has inertia. If you have a big change in the surface of the vinyl, the needle won't be able to track the change. It will jump over a big pit, for example, so you'll have an unknown, uncontrolled period of silence until the needle lands - which further produces an unknown, uncontrolled signal peak.
That's about the big details (a big signal peak followed by small signal). And about small details, the vinyl has a "resolution": the granularity of the vinyl, or the smallest pit that you can actually press on it. Extreme example: you can't engrave a detail smaller than a vinyl molecule.

And that's not even taking into account the need of the vinyl to be in virgin state (so every pit is where it is supposed to be, without any deformation or even wearing out). Nor the need for the turntable being perfectly stable and horizontal and isolated from movement (typically, floor vibrations can be felt in the audio anyway). Nor the need for the needle and arm to be perfectly stabilized as well. And that pesky static electricity and the dust! And those greasy fingerprints!

So, to summarize: vinyl = too many things uncontrolled. If you are thinking you have a perfect reproduction, you are kidding youself. A lot.

If would be less bad if you tried with laserdiscs, which were also analog, but didn't have the needle/arm problem.



A digital recording defines exactly what it records - and what it doesn't. You want more information recorded? you only need to push up the specs.

The point is, you always lose information. With analog, it's difficult to know exactly how much you lose. But with digital recording, you at least get to define exactly which part of the information you want to keep.

And as a bonus, you can then reproduce and process that information with less problems.



So, push for those better specs, of course.
But going analog doesn't help at all.

Don't get me wrong, I don't think that vinyl is the way to go... I just don't think that CD is the way to go either!

 

[pika2000]

Trust me when I tell you these are not audiophile mumbo-jambo!!
If you have speakers >1000€ / pair and a descent amp to drive them, then the difference between 256kb/s AAC and a CD is audible. The more expensive your equipment, the more obvious the difference! If however you use a crapy pair of buds to listen on the go, you probably couldn't tell the difference...
With SACD and DVD-Audio however, it's a different thing! If you hear those formats on a good rig, with a proper setup, on a properly treated room, you will never go back to CD!! (of course I still have some cd's that I cannot find in other formats)
The recordings for those formats are made with microphones that can record up to 96khz (at 192khz sampling) or in some cases even higher! (for other formats - mostly archival at the moment)
One of the key differences between a digital and an analog format is that when you record in analog you have infinite samples! You are recording every pSec of what you perceive as reality. In a digital recording you have a specific amount of samples/sec (hz) which, in the case of a CD, are not enough to capture the whole musical reality!

It is mumbo jumbo. Go do an ABX test and come back.

 

[.Locke]

It is mumbo jumbo. Go do an ABX test and come back.

I have done ABX tests...
Do you honestly think that you cannot hear the differences between a
DVD-Audio or SACD and a CD?
So according to you there is no need for a 24bit/96khz signal?

 

[pika2000]

I have done ABX tests...
Do you honestly think that you cannot hear the differences between a
DVD-Audio or SACD and a CD?
So according to you there is no need for a 24bit/96khz signal?

Then show me the result of the ABX test then.
Who said that there's no need for higher resolution signal? Having archives at the highest resolution possible is great. Buy your audiophile mumbo jumbo is still a mumbo jumbo.

 

[Luba]

All I'm trying to point out is that a sample of 44.1khz is not enough. A higher sample rate not only gives you the ability to record higher frequencies and harmonics, but also captures MORE of the actual music event. That's why DVD-Audio stores files at 24bit/96khz and SACD at 1bit/2.8Mhz
Is it an audible difference? YES... IF you have a proper setup with good equipment...

So the most important aspect is sample rate? I thought the bit rate was the most important as it gives an overall quality statistic. Didn't know SACD sampled at 2.8Mhz!! BUT the bit depth is only 1 bit!! I thought that was a typo so I go to Wiki and find out SACD is indeed at 1 bit for the bit depth, although it's done at DSD (Direct Stream Digital). How is DSD different and perhaps better than PCM (Pulse Code Modulation) that a CD uses?

 

[BubbaMc]

I have done ABX tests...
Do you honestly think that you cannot hear the differences between a
DVD-Audio or SACD and a CD?
So according to you there is no need for a 24bit/96khz signal?

I don't think, I know.

There is definitely a need for 24/96, in digital audio production and editing, NOT audio playback!

 

[.Locke]

I don't think, I know.

There is definitely a need for 24/96, in digital audio production and editing, NOT audio playback!

I'm shocked that so many people think that there is no need for something better than CD! So I imagine that to you DolbyTruHD and DTS-HD MA are a waste of time and resources too? I bet you cannot hear the sound improvement there either...
Just out of curiosity, what speakers-amp-player did you use when you listened to DVD-Audio or SACD?

 

[d0vr]

Why would anyone think that CD quality is a high enough audio quality? I just don't understand. Even before there were HD audio formats I always thought that CD was lacking.

Only now with retina displays where you can barely see the pixel, 4K video, and HD audio where a very large majority of people can't hear a difference (there is a difference between HD audio and CD quality audio) am I starting to feel satisfied with the media formats.

 

[localoid]

Of course instruments produce frequencies over 20k, nobody has said otherwise. People just can't hear those frequencies. Or are you talking about how higher frequencies can change audible frequencies - in that case the interaction happens before the sounds get to the mic so it still doesn't matter that the inaudible frequencies aren't recorded.

...

And NO recording of a violin will sound exactly like the original instrument, but that's a limitation of the mics and speakers as much as any recording medium.

While I agree that limits of current technology prevents the recording of a violin that sounds exactly like the original sound, here's a couple of points to consider...

1: "Several investigators have reported that high-intensity, bone-conducted sounds in the ultrasonic region above 20 kc/sec can produce auditory sensations in individuals with normal hearing" according to this article.

2: Mics that record beyond 20k are readily available, such as the Sennheiser MKH 800-P48 (frequency response of up to 50 kHz) and even DIY ultrasonic mics.

I'll also note that I've taken part in some rather informal experiments where ultrasonic sound was played back over speaker systems capable of >20k sound reproduction. Although I couldn't actually hear any sound, I could begin to feel the sound after being exposed to it for a few minutes. Some of the other participants also began to feel a headache in addition to feeling the sound itself.

 

[BubbaMc]

I'm shocked that so many people think that there is no need for something better than CD! So I imagine that to you DolbyTruHD and DTS-HD MA are a waste of time and resources too? I bet you cannot hear the sound improvement there either...
Just out of curiosity, what speakers-amp-player did you use when you listened to DVD-Audio or SACD?

Toshiba SD-9500 DVD-A player, Marantz Esotec amp, Dynaudio speakers. Also I used a high quality headphone rig and maintain a large DVD-A library.

I used to be of the same opinion, but after studying electronics engineering and PCM communication systems, and doing a series of blind tests I changed my mind pretty quickly.

Fact is, if you hear a difference, it's due to different mastering between the formats (and a majority of DVD-A's use different masters than the CD version, the master is usually more dynamic and not subject to the 'loudness' treatment that most modern CD albums are).

Take a 24/96 WAV or FLAC file. Make a copy convert it yourself to 16/44.1, then back to 24/96. Then do an A/B blind test, using the same (high quality) DAC for both and let me know your result.

SACD is a different story. DSD DACs sound different to PCM DACs, hence the subtle difference in sound.

16bit 44.1khz PCM is perfectly adequate for high quality audio playback. Ever listened on a really good CD player?

And no I don't think Dolby/DTS HD are pointless. Anything lossless is a great deal better than the butchered DD and DTS soundtracks of the past.

 

[BubbaMc]

Why would anyone think that CD quality is a high enough audio quality? I just don't understand. Even before there were HD audio formats I always thought that CD was lacking.

You've never listened using a decent CD player have you?

 

[d0vr]

You've never listened using a decent CD player have you?

No, all they had at the School of Audio Engineering were these really sub standard CD players. It was terrible.

 

[mnmlist]

So is Apple expected to release something this week regarding this topic? HD-AAC maybe? ALAC?

If I read the story correctly, if I have iTunes purchases they would automatically be updated with the new file format and I don't have to do anything? Is that correct?

 

[milo]

Then show me the result of the ABX test then.

Totally agree. What software did you use for ABX? What material? Did the ABX software generate the second version of the file and if not, what was used?

1: "Several investigators have reported that high-intensity, bone-conducted sounds in the ultrasonic region above 20 kc/sec can produce auditory sensations in individuals with normal hearing" according to this article.

And is there any evidence that people can actually hear over 20k in musical recordings? Or just "produce auditory sensations" with sounds generated from a crystal in an anechoic chamber? If people can't tell the difference listening to music in an ABX test, a test like that isn't really relevant.

2: Mics that record beyond 20k are readily available

Lots of things are for sale. But being for sale doesn't mean that they will benefit the end listener.