Can it be possible iTunes MP3's sound as good as an audio CD? - AVS Forum
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post #1 of 17 Old 10-19-2012, 08:20 PM - Thread Starter
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Though I've been researching for a while I really don't have a background for this. Playing an audio CD through my Sony Bluray into an Integra 40.3 and Goldenear Triton II's sounds fantastic. Hooking up my iPod via aux cable to the Integra sounds notably worse. But if I use a Toslink from my mac, iTunes downloads sound as clear as the CD in A/B testing by my ears. My understanding is that when you use the digital out from the mac you bypass the cheap internal DAC and use the one (Burr Brown) from the receiver. However using the "garbage in, garbage out" methodology, how can a 256k (at best) download sound like 16 bit audio? Can the DAC really be that good?
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post #2 of 17 Old 10-19-2012, 10:37 PM
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I'm not saying mine are any better, no experience with your setup, but maybe your ears aren't up to it. Just what is the max bitrate from itunes? I thought they normally did 128 and only 256 in some circumstances but don't download from itunes so not sure. BurrBrown DACs are well considered from what I've seen...but no experience there.

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post #3 of 17 Old 10-20-2012, 12:12 AM
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It's not the DAC. In a fair test (which almost no audiophiles ever do), it is close to impossible to tell the difference between CD and a 256 Kbps MP3, on a typical music program. If you trained yourself very carefully and used what the codec guys call "killer files," you could hear a difference.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #4 of 17 Old 10-20-2012, 10:02 AM
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First, the iPod vs Toslink comparison: You're comparing the analog out of the iPod to a digital stream. Probably not level matched, and not a fair comparison. Btw how much do you think that Burr Brown DAC in your Integra cost? Like mcnarus said, the DACs are not the weak link.

Second, mp3 vs CD. It's hard for most people to tell a good mp3 encoding from its source, whether that's CD, LP, hi-rez, whatever. Nothing unusual about that...it's what every fair test has shown to date. Audiophiles simply refuse to believe it.
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post #5 of 17 Old 10-20-2012, 10:43 PM - Thread Starter
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Thank you all! I'm a newbie to this so maybe I should explain what my thought process has been. For the past six years or so I listened solely to iTunes downloads on an iPod, being oblivious to lossless music. After buying my stereo last year I started to experiment with CD's again and couldn't believe what I was missing for so long and just figured the difference would always be there. I started to buy CD's (great deals on used ones) to convert my library to ALAC and also was planning to give 24 bit downloads a try. That's why I got the Toslink, that was the only way I found not to degrade a 24 bit signal. However when I tried using the cable with the downloads vs. playing a CD I was shocked not to hear a difference--and after everything I've read on lossless that sounds crazy! (although I now understand 24 bit is more hype than anything)

I guess my main question is, how do I get the best sound from my system, am I not looking in the right place? I realize this could be a broad answer but any help will be appreciated.
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post #6 of 17 Old 10-21-2012, 08:06 AM
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Thank you all! I'm a newbie to this so maybe I should explain what my thought process has been. For the past six years or so I listened solely to iTunes downloads on an iPod, being oblivious to lossless music. After buying my stereo last year I started to experiment with CD's again and couldn't believe what I was missing for so long and just figured the difference would always be there.
So you compared listening to AACs on an iPod to listening to CDs on a home stereo system, and concluded that the difference you heard was largely attributable to the difference in sources, rather than the difference between earbuds and loudspeakers. I'm gonna assume you're an intelligent guy who can now figure out the flaw in that thinking!
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I guess my main question is, how do I get the best sound from my system, am I not looking in the right place?
Assuming you're happy with your speakers, the answer is to work on improving your room. As should be obvious by now, everything else is fine.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #7 of 17 Old 10-21-2012, 10:33 AM
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Originally Posted by Mikesculpt View Post

Though I've been researching for a while I really don't have a background for this. Playing an audio CD through my Sony Bluray into an Integra 40.3 and Goldenear Triton II's sounds fantastic.

Good.
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Hooking up my iPod via aux cable to the Integra sounds notably worse.

Your Bluray probably puts out a signal that is about twice or more that coming out of the iPod. A stand-alone home audio optical disc player usually puts out 2-2.5 volts peak. An ipod is usually limited to about 1 volt.

Peak signal voltage differences are usually thought to be different than inherent sound quality differences. If you want to to a fair comparison, you'd first make them the same.

Also, the production that goes into downloads from wherever varies. It is possible for iTunes downloads to have excellent sound quality, but when you start comparing specific files, they are what they are.

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But if I use a Toslink from my mac, iTunes downloads sound as clear as the CD in A/B testing by my ears.

That may go a long way to equalizing signal levels. Or not. Apparently it does.
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My understanding is that when you use the digital out from the mac you bypass the cheap internal DAC and use the one (Burr Brown) from the receiver.

The converters in Macs are supposed to be pretty good. The ones in iPods are supposed to be pretty good. I wouldn't expect any of them to be significantly better sounding than any of the rest in a good, fair test.
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However using the "garbage in, garbage out" methodology, how can a 256k (at best) download sound like 16 bit audio?

The answer is that 256k does not represent enough lossy compression to cause night-and-day signal quality losses, if you actually do a fair comparison. This is especially true if we are talking AAC, but a well-made 256k or 320k MP3 can work a treat.
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Can the DAC really be that good?

Even fairly inexpensive but good DACs can be undetectable in comparisons with a straight piece of wire. Most of what you read from audiophiles and journalists saying otherwise is based on poorly-done listening tests.

Most people are pretty mind blown about what they hear sounding like other things they dispise in well-run listening tests. A lot of current public wisdom about DAC SQ traces back to the bad old days in the early 1980s.
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post #8 of 17 Old 10-21-2012, 07:44 PM - Thread Starter
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Originally Posted by mcnarus View Post

So you compared listening to AACs on an iPod to listening to CDs on a home stereo system, and concluded that the difference you heard was largely attributable to the difference in sources, rather than the difference between earbuds and loudspeakers.

While I'm lost on the finer points of this thread (level matched, peak voltage,) yes, I did know enough not to compare earbuds to floorstanding speakers. The iPod (aux,) mac (toslink,) and bluray (hdmi) were all connected to the receiver and playing the same song and I was just switching between sources.


So it looks like my main misunderstanding is with lossy/lossless files. I was under the impression mp3's of 256k and less couldn't sound good no matter what, once encoded you were better off with a cassette. This is why I couldn't figure out why the mac and bluray were sounding the same, I expected the mac to sound like the iPod. So if I'm understanding this correctly, all I had to do was switch the aux for a toslink?
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Assuming you're happy with your speakers, the answer is to work on improving your room. As should be obvious by now, everything else is fine.

What do you mean by "improving your room?"
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post #9 of 17 Old 10-22-2012, 04:59 AM
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Originally Posted by Mikesculpt View Post


So it looks like my main misunderstanding is with lossy/lossless files. I was under the impression mp3's of 256k and less couldn't sound good no matter what, once encoded you were better off with a cassette.

You've apparently been listening to people who are heavily biased against MP3s and probably feel the same way about other lossy file formats including AAC.

High bitrate MP3s, when compared to original source files IOW .wav files or Flac files, are generally hard to distinguish given that people take the trouble to do a good listening test.

I feel like a !@$ broken record, but almost nobody does proper listening tests before they open their pie holes. The people who develop lossy file encoding software and do formal testing of both their lossy encoders adn the competition generally have very high standards and routinely do very good listening tests.

If you invest 256-320 kbps sized chunks of bandwidth and file space in a stereo music file, it should be very, very hard to distinguish from the original sources. Acceptable performance is that trained listeners can reliably hear minor differences with only a tiny fraction of all music. The rest will stump them.

Comparing a high bitrate or even a modest bitrate music file to a cassette recording is a bad joke. I've never heard a cassette that sounded enough like the original source to make me even listen hard in a proper blind test. I'm including the results of using the best commercial metal tapes recorded on high end cassette machines such as those made by Nakamichi during the golden age of the cassette.

It turns out that well-done blind tests can reliably detect the SQ damage done by the best high speed studio tape machines running on half-track high quality tape running at 15 and 30 ips. In general a well-done MP3 or AAC file can stump the same experts, but there are a few pathological pieces of music that cannot be encoded with perfect transparency. They don't sound bad at all, but trained experts who go over the tiny minority of patholgical recordings with fine toothed combs can hear small differences.

My point is that 15 ips half-track tapes can't be audibly perfect, how good can cassette be if it runs at 1/8h the speed and on tracks 4 times narrower, given that speed and track width are the analog tape equivalent of bitrate?

Bottom line is that no way are you better off with cassette. Back during the golden age of the cassette, a fresh LP played well was generally agreed to sound better. And that is setting the bar pretty low! ;-)
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post #10 of 17 Old 10-22-2012, 05:01 AM
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Originally Posted by Mikesculpt View Post

What do you mean by "improving your room?"

Careful location and orientation of your speakers, the use of custom equalization to optimize the matching of your electronics and speakers to the room, and acoustic treatments such as strategically-located thick absorptive wall panels and bass traps.
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post #11 of 17 Old 10-22-2012, 02:06 PM
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Originally Posted by Mikesculpt View Post

I guess my main question is, how do I get the best sound from my system, am I not looking in the right place? I realize this could be a broad answer but any help will be appreciated.

"the best" is a slippery slope term.

For digital stereo redbook music (ripped from CD disc), store it on your computer's HDD in .flac format and leave it intact. Meaning 16/44.1 redbook format. When playing it back, make sure your OS and software player do not convert it; meaning leave it intact in 16/44.1 format.

While .alac is a lossless format (same bits as the larger file in .wav format), .alac is specific to Apple, just as Microsoft has it's own lossless format.

Beyond that, the best way to get the music out of your Mac is as a digital signal via a digital capable cable. That can be either HDMI or Toslink/optical or coax-RCA or USB. Almost all of my own recent experience is on a PC using a coax-RCA cable for digital output.

With regard to hi-rez (> 16/44.1), leave that to absolute last as it's more complicated and diminishing returns sets in in a very serious way. And don't spend a penny on it. Start with 2L where you can d/l quite a bit of their excellent and *free* hi-rez samples of their stereo and 5.1 music. That gets you some insight as to what additional things you need to do, as well as how much more space it is likely go to take up on your computer's HDD.

The best is the enemy of the good. Voltaire (1694-1778)

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post #12 of 17 Old 10-22-2012, 05:59 PM
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I have a similar experience. I have a PS3, Denon 2112 and Energy RC speakers. CD's sound fantastic, Apple airplay to the Denon from my ipod sounds like absolute garbage... but when I stream those same files from my PC to the PS3 I can't tell the difference from the CD's.

I believe my entire library was ripped using AAC encoder at 256 kbps.
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post #13 of 17 Old 10-22-2012, 07:51 PM - Thread Starter
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Thank you everyone for contributing, you've all been a great help. Mcnarus and Arnyk pretty much nailed my problem: I've spent waaaay too much time reading bad information on the internet from people who thought they knew what they were talking about, and here I thought the web never lied.

It looks as though my setup is where it needs to be for me. Aahhhhh, I can sleep again.

MuaySteve I wish you the best in your quest for high fidelity, you're in the right place with these guys (or girls?) I'll be sure to check back to see if I can learn anything from your situation but I'm certainly not the one to give advice--I'd put you in the same trap that I fell in.

Cheers
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post #14 of 17 Old 10-22-2012, 11:39 PM
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Originally Posted by OtherSongs View Post

For digital stereo redbook music (ripped from CD disc), store it on your computer's HDD in .flac format and leave it intact. Meaning 16/44.1 redbook format. When playing it back, make sure your OS and software player do not convert it; meaning leave it intact in 16/44.1 format.
FLAC is not Redbook. When you record it from the CD it will be a wav that is converted to a FLAC. When replayed the FLAC will need to be unpacked to make it a wav.
Do this and there is no data loss from CD to HDD storage to later replay.
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post #15 of 17 Old 10-23-2012, 06:25 PM
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Originally Posted by A9X-308 View Post

FLAC is not Redbook. When you record it from the CD it will be a wav that is converted to a FLAC. When replayed the FLAC will need to be unpacked to make it a wav.
wav is a specific storage file format. It actually competes with .flac as a "container" format. If you are ripping into .flac/playing, nothing is converted to and from .wav. You are simply compressing and decompressing PCM audio samples to and from .flac file. That operation happens in memory and there is no reason to create an intermediate .wav file to play or compress bits.

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post #16 of 17 Old 10-23-2012, 11:26 PM
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Originally Posted by amirm View Post

wav is a specific storage file format. It actually competes with .flac as a "container" format. If you are ripping into .flac/playing, nothing is converted to and from .wav. You are simply compressing and decompressing PCM audio samples to and from .flac file. That operation happens in memory and there is no reason to create an intermediate .wav file to play or compress bits.
My main point was my first sentence - FLAC is not Redbook. It may be a lossless data compression of what comes off the disc, but they are not the same. You are correct that there is no need to convert it to a wav first and many programs will do the rip and FLAC conversion directly.
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post #17 of 17 Old 10-24-2012, 12:12 PM
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Originally Posted by A9X-308 View Post

My main point was my first sentence - FLAC is not Redbook. It may be a lossless data compression of what comes off the disc, but they are not the same. You are correct that there is no need to convert it to a wav first and many programs will do the rip and FLAC conversion directly.

".flac" music files is an open format with royalty-free licensing and stands for Free Lossless Audio Codec; see: http://en.wikipedia.org/wiki/Free_Lossless_Audio_Codec

For "Red Book (CD standard)" see: http://en.wikipedia.org/wiki/Red_Book_%28CD_standard%29

The best is the enemy of the good. Voltaire (1694-1778)

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