If a CD is copied into iTunes with Apple Lossless Encoding then played by Airtunes via the Airport Express connected to my BeoSound 4, would it be the same quality as the original CD? 

Yes! Lossless mean that there is absolutely no loss dur to the compression.

That depends upon the equipment you are using to listen. There is actually a perceivable difference, as one BeoWorlder could study last night stating Apple Lossless was rubbish compared to the original CD:

http://forum.beoworld.org/forums/permalink/1154/9443/ShowThread.aspx#9443 

A CD has 16 bit depth and samples the sound at a rate of 44.1 kHz. With 16 bit audio you have 65,536 possible levels the audio energy can be sliced at any given moment in time. The sample rate then decides how many times per second that depth is registered. WIth a CD that comes out at 44.100 slices every second. (Good CD players will upsample that rate by multiples through the DAC).

Audio information with such richness takes up a lot of space. A three minute song at the CD density fills up 30.3 MB, with a bit rate of 1.35Mbit/sec.
An mp3 file needs 2.82 MB to describe the same song, and does so at a bit rate of 0.13Mbit/sec (the standard sample rate of 128kbps) - coming out at about 9% of the original file.

Apple Lossless seeks to capture as much of the audio information as possible, while compressing the size of the original file to between 40-60% (measured). The codec is such that one is not supposed to be able to hear a discernible difference on standard HiFi equipment -- however, if you have good equipment you will hear a difference.
Audiophiles are exploring playback with 24 bit sources giving them 16,777,216 levels of audio. Sample rates can be much higher than 44.1 kHz. THe purpose of achieving these higher rates is to ensure that the original sound is captured with a fidelity that makes it impossible to distinguish it from the recording. Sound engineers claim that such systems achieve total transparency from source to playback.

Apple Lossless, while doing a good job compressing files, does not deliver such transparency. The soundstage is smaller and the various "voices" constituting the sound are less defined. Still for most purposes quite acceptable, and preferable to the sample rates that are usually used to fill iPods with music.
On my audio system the difference is clearly noticeable, as it also was for philipsmz333 when he compared the formats through his new BL5s.

The Lossless Audio Blog is an excellent resource if you want to learn more about this:

http://www.losslessaudioblog.com/ 

soundproof:

That depends upon the equipment you are using to listen. There is actually a perceivable difference, as one BeoWorlder could study last night stating Apple Lossless was rubbish compared to the original CD:

http://forum.beoworld.org/forums/permalink/1154/9443/ShowThread.aspx#9443 

Strange. I'm quoting the actual website that you are referring to: "Lossless audio is audio that preserves audio quality and is identical to the original file. When a CD is compressed to a lossless format there is no loss in quality or data resulting in a exact clone of the original file. Lossless audio files are compressed using various techniques to achieve a smaller more manageable file size. One way to think about lossless files are to compare them to a Zip file, a lossless file is compressed to reduce the size of the file and as it is played it is uncompressed revealing the original quality." Any differences you have experienced are probably due to playback software and/or different d/a converters.

But does the Airport Express also alter the file when it broadcasts it and then does the BeoSound 4 loose anything compared to the BS4 laser reading the information direct from a CD? 

I'm thinking of re-importing my CD collection with iTunes as Apple Lossless in order to get the same quality as CD. I can definetly tell the difference with mp3 at different bit rates and obviously want the best quality with the convenience too.

Actually, transfer from the computer to the Airport Express and on is bit-to-bit true. Stereophile tested this thoroughly, with comparison of files before and after transfer, and found a 100% match when they pulled the signal out of the Toslink optical of the Airport Express. (The same minijack connector supplies a line out and an optical out signal).
However, the DAC (digital to analog converter) inside the Airport Express is not top notch, which means that when you're using regular analog line out from the AE you're getting a reduction in signal resolution.
I like the convenience of iTunes and AE. All my favourite music is sampled at Apple Lossless or in a very few instances uncompressed AIFF or WAV (which iTunes recognizes). Music I enjoy, but wouldn't sit down to listen to attentively, I sample at 320/192. This helps me get room for more on the harddisk.

For all practical purposes, you will get a very acceptable sound out of Apple Lossless - but it's not the same as what's on the CD.
Attempts have been made to reverse engineer the Apple Lossless codec, and there's little doubt that it's a very good one. However, it's a variable sample codec, which means that it will analyze the density and complexity of a track, and then set sample rates on the fly, within its parameters, adapting to the music. This means that it - to some extent - evens out the information that's there, trying to trick the ear while achieving compression. (Just look at the bitrates of the various tracks of an album you've compressed with Lossless. You'll find that each track is sampled at a different bitrate due to variable algorithm employed).

I would think that going straight from the CD in your BS4, to your BL8000s, will give you a richer sound than going from Lossless to AE through a cable to your BS4. But switching CDs isn't handy - and Apple Lossless if far preferable to lower bitrates, still giving you more room for storage than if you went uncompressed.

There's one problem I've noticed with using Apple Lossless. My car's audio system doesn't recognize the Apple codecs. It will accept music that is uncompressed or in MP3, but not the MP4 Apple is using. Which may mean you'll have to recompress music for such uses.

henrik:

soundproof:

That depends upon the equipment you are using to listen. There is actually a perceivable difference, as one BeoWorlder could study last night stating Apple Lossless was rubbish compared to the original CD:

http://forum.beoworld.org/forums/permalink/1154/9443/ShowThread.aspx#9443 

Strange. I'm quoting the actual website that you are referring to: "Lossless audio is audio that preserves audio quality and is identical to the original file. When a CD is compressed to a lossless format there is no loss in quality or data resulting in a exact clone of the original file. Lossless audio files are compressed using various techniques to achieve a smaller more manageable file size. One way to think about lossless files are to compare them to a Zip file, a lossless file is compressed to reduce the size of the file and as it is played it is uncompressed revealing the original quality." Any differences you have experienced are probably due to playback software and/or different d/a converters.

Hi Henrik,

Yes, that's the enviable goal of lossless compression. Yet opinions are, mildly stated, mixed as to whether it's been achieved - with numerous formats jousting for which does the job. And good ears will tell you it's "close, but no cigar."

Lossless sound compression algorithms can take advantage of the repeating patterns shown by the wave-like nature of the data - essentially using models to predict the "next" value and encoding the (hopefully small) difference between the expected value and the actual data. If the difference between the predicted and the actual data (called the "error") tends to be small, then certain difference values (like 0, +1, -1 etc. on sample values) become very frequent, which can be exploited by encoding them in few output bits.

 Close, but no cigar. I want what's there, not a close approximation with the goal of compacting the data. Hard drives are so cheap now that we can begin storing our music uncompressed. And soon we'll be buying it in 24-bit resolution as downloads (already available from specialist suppliers). Just one of many getting ready: http://itrax.com/

That is what I was thinking. With cheap hard drives these days, I want to make an exact backup of all my CD's at the same quality. Then be able to play these tracks via my BS4 knowing that I am listening to the best copy possible.

britops:

That is what I was thinking. With cheap hard drives these days, I want to make an exact backup of all my CD's at the same quality. Then be able to play these tracks via my BS4 knowing that I am listening to the best copy possible.

Have you considered using a Network Attached Server? You can have 1 Terabyte of storage space (well, sky's the limit) and put your photos, HD-video, DVDs and CDs on it, in original quality.

The best one I've come across is Infrant's ReadyNAS NV: http://www.infrant.com/products/products_details.php?name=ReadyNAS%20NVPlus

Very easy to set up. Uses RAID protection of the data, which means that a hard drive can fail (it's got four) and you still have everything. Your iTunes will see it on your network as a shared Library. (Comes with Slimserver installed). MacOSX and Windows compatible.

About GBP 750 where I live. 

 

 

soundproof:

Hi Henrik,

Yes, that's the enviable goal of lossless compression. Yet opinions are, mildly stated, mixed as to whether it's been achieved - with numerous formats jousting for which does the job. And good ears will tell you it's "close, but no cigar."

Lossless sound compression algorithms can take advantage of the repeating patterns shown by the wave-like nature of the data - essentially using models to predict the "next" value and encoding the (hopefully small) difference between the expected value and the actual data. If the difference between the predicted and the actual data (called the "error") tends to be small, then certain difference values (like 0, +1, -1 etc. on sample values) become very frequent, which can be exploited by encoding them in few output bits.

 Close, but no cigar. I want what's there, not a close approximation with the goal of compacting the data. Hard drives are so cheap now that we can begin storing our music uncompressed. And soon we'll be buying it in 24-bit resolution as downloads (already available from specialist suppliers). Just one of many getting ready: http://itrax.com/

Lossless compression IS lossless, you've got your facts a bit mixed up*. Any differences you hear are due to differences in DACs (as you wrote before, the DAC in the Airport Express isn't exactly topnotch but this has nothing to do to with the lossless audio compression) or placebo. This is a fact. If you compare the checksum of the un-compressed file and the lossless compressed and decompressed file you will find that the checksum is the same, so the files are bit-to-bit identical.

It's like compressing a TIFF image file with zip compression - the compression will not alter the original data, the de-compressed file will be bit-to-bit identical with the original file. You can also use a lossy compression algorithm like JPEG and if you choose to do a very high quality JPEG version of your TIFF file, you'll probably won't be able to see any difference but if you compare the actual file data you will se that they are different. It's the same with audio files - if you use a real lossless compression algorithm the sound files will be identical, but if you use a lossy algorithm (such as MP3 or OGG) there will be a difference in the data and you'll maybe be able to hear it.

*What the text you quoted actually means (if i understand it correctly, hehe ;-) ) is that in lossless compression one of the tricks is to describe changes instead of re-stating the actual data/state in every bit. This means that you describe the data in a more "economic" way. Let's say you are monitoring how many people there are in a supermarket. You can do this like "now there are 1356 people here, oops now there are 1355 people here, oh now there are 1357 peple here etc etc". If you instead put this like "Now 1356 people, now -1, now +2 etc etc" you've managed to keep track of the people count using shorter descriptions than before. Lossless compression ;-)

Hi Henrik,

I believe we are talking around one another here.

One point is whether the information stored is the same; another is whether it is played back identically. See below for the first. As I have mentioned in this thread, there are strategies for ensuring that your music reveals the integrity of the original in your room. But thinking that what you get out of Apple Lossless from iTunes is the same as you hear from your CD, without applying those strategies, is wrong.

This is Britops' question:

If a CD is copied into iTunes with Apple Lossless Encoding then played by Airtunes via the Airport Express connected to my BeoSound 4, would it be the same quality as the original CD?

My answer was no. And still is no.

The point you make is that the lossless file is identical to the original file; the point I make is that it won't play back the same unless you are aware of what's happening to your signal on the way. The Airport Express (AE) DAC (digital-to-analog converter) is a cheap one - but the AE can output an optical signal, which means the digital information can remain intact out of the AE. However, since the BS4 doesn't have digital IN, that system won't preserve the integrity of the data. If it was able to recognize the digital source, it could pass it to its own (one hopes better than Apple's) DAC, and then Britop would hear the same from his stored file as he would from a CD in the BS4.

As to files matching. The data will show checksums that match up . (See the bottom of this article, for instance: http://www.bobulous.org.uk/misc/audioFormats.html

For each track, the MD5 checksum of the Wave file converted from FLAC matches exactly the MD5 checksum of the original Wave file. The file sizes match exactly, too. This is very strong evidence that FLAC really is lossless.

There's still discussion on the "very strong evidence" bit. I am personally uncomfortable with the "it's just silence, so that can be described as such in a compressed manner" element of variable lossless compression.
I am very pleased with the sound I get from Apple Lossless on my Apple computer configured as media center through TOSLINK optical to my Benchmark DAC-1, which is then processed by my new (!) Beolab 5000 amp and routed on to its speakers. I'm still more comfortable with playing a CD through the system when I really want to sit down and listen, though. Subjective? You bet! To support your point, I wouldn't swear my ears can tell the difference through that setup.

At any rate, and possibly more important, the use of compression -- both lossy (where you lose information in the data) and lossless (where the checksums match) - came about as an answer to the fact that hard drives and other storage devices were very expensive, and also much smaller than today's.
I paid more money some years ago for my first LaCie with 30GB capacity than I paid for the Infrant NAS I mentioned above, which has 1 Terabyte of capacity and can work as a computer independent server! Today we can easily store all our music and films in the original  formats and not have to worry about any loss of information at all. Sound engineers and audiophiles I know well clearly prefer the uncompressed lossless digital formats to the compressed ones (such as Apple Lossless, Shorten, FLAC, etc.)

I just wish that my ears weren't going to be 50 soon. But the BL5s in my soon ready for prime time music room will make up for my head turning into concrete!

 

 

Yes, you're talking about the limitations of the Airport Express - not about the Apple Lossless format! I didn't think you stated this clear enough before, hence my post.

If the DAC in the BS4 is better than the one in the Airport Express, you'll of course get better sound from the cd in the BS4 but this has of course to do with the Apple Lossless format, it only has to to with differences in DAC quality (as you write in your latest post)

"I am personally uncomfortable with the "it's just silence, so that can be described as such in a compressed manner" element of variable lossless compression."

Lossless is lossless, full stop. Pls see my "people in the supermarket" example. The expanded data is identical to the original data. There is no need to have worries such as the one expressed above. I think that maybe you are a bit confused regarding the differences between lossy algorithms (that uses various psycho-acoustical tricks to reduce the original audio data) and lossless algorithms (that doesn't affect the original audio data, only storing the data in a more efficient way). Why I wrote my first reply in this thread was because I thought that your post could be misleading to the forum members that do not know what lossless data compression is.

henrik:

I think that maybe you are a bit confused regarding the differences between lossy algorithms (that uses various psycho-acoustical tricks to reduce the original audio data) and lossless algorithms (that doesn't affect the original audio data, only storing the data in a more efficient way).

Hi Henrik,

As you'll see from my previous post, I'm aware of the differences between lossy and lossless compression. My answer to Britops dealt with his setup, though did also extensively refer to the perceived lack of transparency in Lossless compression formats when played back. However, as you point out - the data compares between the CD and the Apple Lossless format. The sound out rarely does, as I point out.

Very few people have digitally preserved data chains from stored source to excellent speakers (or their amp) - which means you can not expect a similar sound as that from a CD when using, for instance, Apple Lossless.

Here's the Stereophile article that inspired me into attempting to achieve digital transparency from my Mac. You may find that interesting:

http://www.stereophile.com/accessoryreviews/505apple/index.html 

And here's another on the challenges of doing the same with a Sonos. (There's also a good Stereophile article on the Slimdevices Transporter): http://www.stereophile.com/mediaservers/1006sonos/index.html

Now - what I want is the ease of use of iTunes/Frontrow on the Mac, combined with the great overview and interaction of the Sonos remote, with the quality of the Slimdevices Transporter, without Apple's "you don't need the extra resolution" (see first link), using uncompressed files, piped to B&O's speakers.

It looks like I'm going to get it by using a dedicated wireless capable PDA with Salling Clicker installed, controlling the Mac and thus accessing my NAS, with a Transporter for the main listening room's top speakers and AEs for other rooms, in some with a separate DAC linked to the speakers.

 

What you have to remember is that when iTunes imports something with lossless, while there is no compression going on, QuickTime does do things to the CD when importing it.

Lossless encoding is... lossless: when decompressed the file is idfentical to the original one. Like when you unzip a word document, you haven't lost a letter.

wtlc2zpx:

Lossless encoding is... lossless: when decompressed the file is idfentical to the original one. Like when you unzip a word document, you haven't lost a letter.

However, some CD player may be better at rendering a CD than the Airport express D to A chip.

I would think most CD players with a half decent DAC, if you're using the analog out of the Airport Express. Interestingly, to get bit transparency out of a Mac you have to set the Output Volume to maximum. If you reduce it, the conversion to lower volume reduces the fidelity of the output. Likewise, one should also always set the sample rate of the output to that of the source, which you have to do manually if you switch sources. (Using the Midi app).
If you don't do this, then you won't have true bit transparency even when using the digital out connection on a Mac with OSX.

Found this out when I bought my Benchmark DAC-1. The manufacturer had tested Mac output signals and found the above necessary.