Maximum bit rate and sampling frequency on iTunes and iPod

Hi there folks,

 

could anyone please tell me what the maximum bit rate and sampling frequency is supported by iTunes and the iPod.

 

That is, can us iPod users get the most out of Linn HQ releases for example?

 

As an aside, after all my years chasing that elusive high end sound, spending thousands of dollars, I have finally found the most musically satisfying sound via my iPod video 30gig and a pair of Sennheiser 580 Jubilee headphones. Just bliss.

 

Hi baxtus - First I have to say you are one lucky person since you've found sonic bliss with a relatively inexpensive system! Now you have much more money to spend on music. It doesn't get much cooler than that. My iPod will not support any of the 24/96 content I've downloaded from Linn, iTrax or MusicGiants. So, to answer your question iPod users won't get the most out of this high resolution content on their current iPods. Hopefully the future will lead to 24/192 iPods!

 

Have you tried a separate headphone amp connected to your iPod?

 

Hi Chris,

 

Thanks for your reply.

 

Yes, I hope that iPods in the futeure support 24/192.

 

I have a modified Simon Busbridge design tube headphone amp. It does the "audiophile" stuff better than the iPod but doesn't deliver the "music" like the iPod straight. If a piece of equipment consistently allows the music to move me, then I consider it to be doing its job. The iPod via those Sennheisers just do it. So yes, I'm a lucky man!

 

 

 

Hi.

I've asked some days ago to the guy of "Rockbox" something like you ask now... They make a software for many players and it seems to playback also .flac 24/96 files...

here is the link...but...you have to try and please write (here!!!) back.

Ciao, Luca

 

(my 100 cents ;-)

 

 

http://forums.rockbox.org/index.php?topic=16289.0

 

Hmmm, I'm not to sure about all the stuff mentioned in that thread. USB 1.1 can and will carry a 24/96 stream natively given the right equipment. My Benchmark DAC1 PRE does it right now.

 

Using Rockbox for high resolution content is a bad move. It downsamples everything to 16/44.1.

 

When I read a statement like this:

 

"That said, 24/96 playback is pretty useless anyway. Just use 16/44.1 and stop worrying."

 

I have to seriously wonder about the source of the information.

 

;-)

 

 

Yà, rock...spresso: what else!

 

As a newbie to this forum, I wanted to post a few things I've learned about this. As a point of reference I have an ipod classic 80GB, and am running iTunes 7.7.1.11.

 

I have discovered that I am able to import 24/96 .wav files into iTunes and convert them to Apple Lossless format at that same resolution. However, I cannot sync them to my ipod. But I can downconvert them to 24/48 .wav files, then convert to Apple Lossless and sync to my ipod fine.

 

As mentioned earlier in this thread, I don't know whether the ipod is actually using all 24 of those bits. And even if so, it's questionable whether the electronics inside the ipod or the headphones we typically use with ipods are of sufficiently high quality to show the difference. But at least I'm glad to see that Apple has provided this capability in their file formats. This is useful when listening in iTunes on my PC today, and perhaps it portends some kind of "audiophile ipod" in the future.

 

Not to thread hijack, but does the relatively high 300 ohm impedance of the HD 580s have a noticeable impact on dynamics or maximum volume when listening through the iPod touch?

 

Hi Chris,

 

If iTunes won't stream 24/96 over USB, is there a system that will?

 

iTunes can play up to 24/192. It's a hardware limitation you'll run into. The airport express is limited to 16/44.1. There are a few really good 24/96 USB DACs as well. The only wireless 24/96 component is the Transporter from Logitech.

 

I don't know whether this question was addressed to me but I will attempt to answer it anyway.

 

I have an older 30G iPod video, not Touch.

 

I have no trouble at all getting full range music at a realistic level from my Sennheisers out of my iPod. It may not be enough for some "audiophiles" who insist on brain and ear damaging levels to get their kicks.

 

I have to say that an enormous influence on sound appreciation is the listening environment and whether one is in a frame of mind conducive to letting the music speak. So many errors of judgement and so much time and energy is wasted on high end audio equipment by those who do not listen correctly.

 

Hope this helps

 

Baxtus

 

As a hi fi manufacturer I have to be extremely carefully not to give the impression that we don't care about about sound quality or are not meticulous enough about assessing it. Nothing could be further from the truth.

 

There is much interest in 24 bit recordings and higher sample rates and people are beginning to see them as the next jump in sound quality. I suspect they are going to be disappointed.

 

Only a small proportion of material sold as 24 bit is, most is older stuff regurgitated. It was often made on Analogue Tape recorders and older equipment so really only has 11 bit resolution. Not only that but a really well produced but compressed recording can sound better than a full 16 Bit file. Someone came here the other day with Wade in the Water by Eva Cassidy and I had a 128K version in the Laptop that sounded better! Same singer same song different production and the MP3 was better!

 

This means that it's too early to tell yet how good 24 bit material can sound - we need much more to choose from before it is safe to draw conclusions. I think everyone agrees that well produced and full 24 bit throughout production should sound better and that this is because the process involves sacrificing bits. The more you start with, the more you finish up with, which has to be an improvement. However, the big question is whether a full 24 bit master dithered down to 16 Bit so streaming it is more reliable or whatever, will sound worse. Frankly I doubt there will be a difference, though I understand everyone will want to prove that for themselves.

 

Another point that Martin Grindrod has made is that very high sample rates are in RF territory and that brings in more problems than it eradicates, so the advice is that you must be able to play up to 24/192, but that it probably won't matter if this is dithered down to 16/44 or whatever for an iPod. I know this will cause consternation and I can explain why in great detail if I have to, right now I'd prefer to leave it open and warn anyone who can hear differences that proper double blind listening tests are necessary because the ears are fooled too easily.

 

As a Manufacturer we're in a different position because we don't know what our customers are going to listen to, all we know is that whatever it is, it must sound as good as the technology will allow. I'll give an example; I have a friend who specialises in restoring old 78s, the results he achieves are remarkable and include a 1911 recording of Sophie Tucker singing Some of these days - it is wonderful to listen to and it astonished people at the Bristol Show when we used it for DEM. I was surprised at the numbers who enjoyed, but one chap asked for something modern and preferably Amy Winehouse. This was played and it was less well produced and less pleasant to listen to.

 

The message is that great music transcends all the barriers and that the number of bits is irrelevant if the recording is crap, so put the music first and make sure your system will play everything really well, that way you can expand and diversify your collection without nasty surprises.

 

Just my thoughts

Ashley

PS. Email the company and I'll send Sophie Tucker to you.

 

Hey hey Ashley - I agree 100% that good music transcends all barriers and the number of bits can be irrelevant. A 24/192 dog bark is still a dog bark. An 8 bit Billie Holiday recording can still cause goose bumps.

 

Listen to Ashley folks!

 

I wish I had read his commentary 5 - 6 years ago,

before I went through the struggles and expense that I did,

in trying to figure out what matters most in audio.

 

I discovered, as many of us have, there are infinite numbers

of ways to separate oneself from one's money in pursuit

of audiophile bliss. But all too often, to no avail.

 

This amp, that amp, cables ( cables cables cables ), DVD-A

players, and on and on. I bought some DVD-A recordings

that are among the most awful recordings I've ever heard!

 

I was lucky enough though, to have the chance to audition a swarm

of XLR cables and speaker cables, lent from my local high-end

dealer, for a long winter weekend. They were swapped into $6,000

of Arcam's best electronics, and $4,500 monitors.

One typical result: in double-blind-tests a

$2,400/pair XLR interconnects were not a bit different

than a $30/pair from BlueJeans cable. Not one bit!

( A statistician friend gave me the parameters for reasonable

double-blind testing, which I can share here, if anyone is interested. )

 

Just MHO ...

It's the recording, first. Some of the best recordings

I have are from Reference Recordings. I use a Dick Hyman recording

from them, HDCD "FROM THE AGE OF SWING" as one of my

references now. If the recording is crappy, you can't buy

enough gear to help. My naivete about this important point is

responsible for most of the cash that got away. ;-)

And so many recordings are crappy, especially if one uses some of Reference Recordings as a standard.

 

It's the speakers second, and the room third, including

speaker placement in the room of course.

Everything else is way down the list, except probably

active vs passive, but I know too little about that to

comment. ( Although it's my current pursuit ).

 

DACs? Double-blind testing here would be prudent too. :-)

 

You might want to read this article, scroll to headline:

 

http://www.theaudiocritic.com/plog/

 

"Proven: Good Old Redbook CD Sounds the

Same as the Hi-Rez Formats".

 

The following resources might be helpful too ...

 

http://sound.westhost.com/bi-amp.htm

 

http://www.bruce.coppola.name/audio/wisdom.html

 

http://www.theaudiocritic.com/downloads/article_1.pdf

 

 

Hi mpmct - Thanks for the detailed opinion. Even though I don't agree with all of it, I do agree with some and I respect the honesty. I am also a huge fan of Reference Recordings. Have you tried the HRx 24/176.4 material? It's absolutely stunning in my opinion.

 

Hi Chris,

 

BTW, love what you have started here with Computer Audiophile.

 

I'm waiting for the nice people at Bel Canto to release their probable(?)

upgrade for my DAC3. They told me a month or so ago it was planned,

but not for certain, at least as of that moment. I had read about the possible

upgrade here, in your article on the subject. It's something I will do if

the price is reasonable. I'm definitely curious ... but absolutely skeptical. :-)

 

FWIW, here's the information my statistician friend sent regarding blind-testing.

The first article is something I ran across, and sent to him for his comments,

which follow the first article.

 

Best regards,

 

Michael

 

.............

 

 

 

 

"Double blind testing

 

How to conduct a double blind test.

 

Buddy has just spent the equivalent of a trip to the Bahamas on a

pair of interconnect wires. You challenge him to a duel. You tell him

that your $10 cables sound the

same as his "Bahama" wonders. Not wanting to look like an idiot he

goes for the bait. Offer him $100 if he can identify which cable is

which. If he can't he pays you $100.The test is 20 trials of either

cable "A" or cable "B".

Instead of tossing a coin you can go a bit high tech. With your $7

pocket calculator you can use the random number generator. Any

number from 001 to 499 can be cable "A" and 501 to 999 is cable "B".

Should the number 500 appear you can toss it out. Have a third party

poke the calculator and jot down the sequence 1 to 20.

 

Now the test begins.

Both you and Buddy leave the room. The 3rd party connects according

to the chart A or B. 3rd party now leaves the room. From this point

on no one knows which cable is in the circuit. Do this 20 times.

 

There can be no communication whatsoever with the 3rd party! No one

has ever been able to determine which is which. By sheer guess

you'll get 10 out of 20. Statistically you must score 17 or so.

After all, if the expensive cable was so much better when sighted

surely you should be able to pick it out by just listening... Buddy

will come up with every excuse you can think of. You can remind him

that he heard the difference when the test was sighted. Now take his

$100 and split it with the 3rd party. Order pizza."

 

 

................

 

Statistician's notes on the above ...

 

"Technically, the experimental design is a repeated measures design with 20

trials of measuring one variable that can take on two values: correct or

incorrect. If Buddy got 17 or more right out of 20, the probability of that

happening by chance is calculated with the formula for binomial probability:

 

http://faculty.vassar.edu/lowry/binomialX.html

 

With n=20 (trials), k=17 (correct choices), and p=0.5 (probability of a

correct choice by chance on a single trial):, the page shows the probability

(for a two-tailed test under "hypothesis testing") as 0.0026. This is

actually a more stringent test than is usually used. I would be satisfied

with k=15, which would happen by chance with a probability of 0.04, which is

close the traditional value of 0.05.

 

Actually, when I read the description of the experiment a second time, I saw

a number of flaws, even though the basic idea is correct:

 

1. The experiment as described is not as sensitive as it could be. People

are best able to disriminate between two choices when they are able to

compare them side-by-side. In the case of audio stimuli, this means hearing

them one after another. A number of protocols have been developed for doing

this. For example, there is the ABA test. In this test, you would hear a

piece of music played with Cable A, then a piece with Cable B, and then a

piece with A or B. The subject's task is to say whether the third case is

the same as the first one they heard or the second. This is not a preference

test, but simply a discrimination test, which is the most sensitive kind of

test: if you can't tell the difference between two cables the question of

which one you prefer doesn't arise.

 

2. Nothing is said about balancing the number of trials of A and B. The way

it's described, the trials could all have been with A if that's the way the

calculator happened to generate random numbers. That would not be good.

There really should be equal numbers of A and B, tested in random order.

 

3. Nothing is said about what sounds are played with each cable. These

should be randomized or balanced. In randomization, you would start with 20

selections of music, for example, and randomly assign them to be used with

Cable A or B. In a balanced design, you would start with 10 selections and

use each equally often with Cable A and B. This would probably not be a good

choice because people might judge differently when they heard the second

repetition of each selection during the 20 trials. This would introduce

extraneous noise into the experiment.

 

4. The sample of people used in the experiment is only one. A better test of

cables would use a much larger sample of people so we could generalize the

results.

 

Hope this helps."

 

 

 

 

 

 

 

Hi Michael - Very cool post, and thanks for the kind words about this site.

 

I agree with Ashley's perspective. I have also found that the quality of the recording and mastering is vastly more important than the media over which the music is played. But it's easy for us home listeners to focus on the media, simply because it's easy to understand and under our own control to change. For example, we "know" that a 24/192 DVD-A must sound better than a 16/44.1 CD because this has been proven in labs with test equipment. But we're talking about differences here that are minute compared to the quality of the recording, not to mention often impossible for humans to hear.

 

Turning to equipment, I want to second mpmct's point about speakers/headphones and room being the most important factors we can control. I would include equalization as part of "room" with the caveat that humans generally don't prefer purely flat equalization so feel free to play with that. I've also heard significant differences when significantly increasing my amplifier power. For the record, I have NEVER heard a difference when switching interconnects.

 

 

 

Want to add that I hope ( and suspect ) that proliferation of hi-def

capability will nurture more of the best possible recordings in the future.

I'm all for that, and I'll be a buyer.

 

At the risk of entirely hijacking this thread, I want to pass along

something I ran across the other day. I've ordered these recordings,

but have not yet received them.

 

Snippet:

 

Ray Kimber ( Kimber Cable )

 

"IsoMikeTM (“Isolated Microphones”) is an experimental acoustic baffle

system, designed to address the interference of intrachannel sounds

that results in compromised fidelity. For these 4-channel recordings,

the microphones were suspended on four arms, separated by IsoMike

baffles. Most baffles absorb sound from mid- to high-range frequencies;

lower frequencies are more difficult to absorb. Here, the unique

shapes of the IsoMike baffles are advantageous. As lower frequencies

flow around the heart— or egg-shaped baffles, they are scattered,

effectively dissipating their energy. Eliminating line-of-sight between

the microphones seems to lower some fidelity robbing cancellations,

which reveals a layer of extreme detail and a sense of increased sensitivity.

We took great care, therefore, to reduce the noise level within

the auditorium during the recordings. —Ray Kimber"

 

http://www.frystreetquartet.com/recordings.php

 

Hey Michael - I have these recordings. They really do sound wonderful.

 

Thanks Chris. I'm looking forward to them that much more then.

 

Best regards,

 

Michael

 

 

 

 

Just received a follow-up note from my friend the statistician.

I've redacted an individual's name in his commentary.

Of course this begs the question of the quality of equipment

used to deliver the audio signals to the subjects ...

 

 

"I've always believed that much high-end audiophile equipment differentiates

itself in a region of the audio spectrum that the ear can't even detect or

with a time-precision that the brain doesn't process. In other words, a lot

of it is hokum designed mainly to separate audiophiles from their wallets.

 

[ Name redacted ], a guy who used to work at [ behemoth US telco ], did a project related to

this. He wanted to find out whether there was any audible difference between

records and CDs. At the time, audiophiles were claiming that CDs sounded

worse than records. So [ Name redacted ] got together a bunch of music (of all types)

that had both CD and record versions (without re-mastering I believe). He

played them to subjects (college students) using an double-blind ABA

discrimination test, if I recall correctly. The result was that not one

subject could reliably tell the difference between record and CD. If follows

that whatever preference they might have had for one over the other had

nothing to do with the way the music sounded."

 

 

 

Certainly interesting, but I respectfully disagree with any coclusion drawn from this test. I think a better test would have used audiophiles rather than college students. I know if I took part in a wine taste test I would say there is no difference between any of them. I think asking the experts on any given subject is the best route :-)

 

Who is an audiophile and who is not?

 

Draw that line with precision, and I'm with you. ;-)

 

"So, I recommend that you depend on blind (or better, double blind) testing to find out answers to questions about the audibility of effects like 96 kHz. sampling rates or 24-bit words." ...

 

http://www.moultonlabs.com/weblog/more/wacky_world_of_blind_testing

 

I'm just interested in whatever is closest to the truth: reality.

It's more interesting and more helpful than this or that opinion.

Even the (arguably) best engineers in the world rely on double-blind testing.

 

Why would they? If their ears aren't golden ... whose? ;-)