iPod Classic... DAC and output stage info from Vinnie of RWA - Page 13

Ken - any update? Inquiring minds and scared wallets want to know.

Yeps, no differences heard and measured:

http://www.hifivoice.com/audio/ipod/...surements.html

Spend some more time on observing intermodulation distortion, that seems to be more prominent in the 6G.

Marc

Is there anyone else out there who can do the same measurements? Maybe Marc's particular unit is bad.

Well, I went back to my friend's 6G classic and compared my 5.5G and his again, but also to my Sony portable CD player with optical out through my iBasso D1 DAC/AMP.

The problem is that they both sound equally as bad, when compared to the DAC in the iBasso with a CD and optical out

It seems that without the iBasso, the 5.5G sounded better with our live classical and jazz recordings, and the 6G sounded better with rock and hip/hop and electronic. But, only by a small margin. I could live with either if I didn't have anything better.

The MP3 we used in the iPods were 320kbps VBR files, so when I got home I tried the iRiver with optical out. It still beats the iPods. I didn't have time due to an asthma attack to listen to the iRiver headphone out.

So you were using lossy files w/ the mp3 players and an uncompressed lossless wave on the CD player for comparison?

(1) The CD optical out to DAC/AMP was THE reference point to see which iPod sounds closest to the point of reference - Not to see if lossless sounds better than lossy. I'm sure you understand that.

It's easier for one person to claim whether he likes the 5.5G better than the 6G, but without a point of reference it is too subjective (i.e. more subjective than what we did).

(2) Also, I did test the same lossy files (320kbps VBR) on the iRiver, when I said that the iRiver was better with optical out to DAC than either iPod.

I DID NOT say it matched the CD player (but it was extremely close). I suppose it is my fault that I didn't make it clear that the files on the iRiver DAP are the same lossy files as tested on the iPod.

(3) Now I can't test the headphone out of the iRiver vs the iPod because it wont power up. I was working earlier I will wait till my used H140 arrives on Monday before I do more testing (my 2 week old spare refurb H120 is still sealed in box and I don't want to open it yet).

(4) One thing this experiment made clear to me is that I WILL BE DOING AN IMOD on my 80gb 5.5G, because they seem to be more reliable than an iRiver with optical out, and more convenient than a CDP with a bunch of CD's in a case. I spent too much money on all the other optical out sources, amps and phones to do it right now.

PS: I will be rolling the opamps on my D1 to the best combination that has been found as of last week, to improve the analog input sound quality for when I do the iMod.

With the H140 I will have more room for lossless files. But the 320kbps VBR are good enough for when I can't pay attention to all the details but want to enjoy it without noticable artifacts. I actually think some of my 192kbps mp3's via optical to DAC/AMP are still very good until I compare them to the CD player, while the 320kbps are almost indistinguishable.

Also, you saw this part, right?

So yes, there is a difference, and for some people it wont be a deal breaker. For me it turned out to be a deal breaker, and I want to iMod my 5.5G 80gb.

Thanks for making me do an A/B comparison, as opposed to listen at diff times...

It may be the case that all iPods can be improved w.r.t. some chosen reference, but that doesn't make a comparison between the 5G and 6G less subjective.

Selecting some reference doesn't make a comparison more valid. You could for instance ask yourself how close an iPod sounds to an 78rpm disc player, that doesn't make it more objective.

The results will also depend on the music and headphone chosen. For instance, my Sennheiser HD650 reveals much more than my Sennheiser HD497, or my Etymotics ER-4P/S. The outcome will be subjective anyway if sonic observations are not performed under double blind test conditions, or without performing measurements as a backup for some observations. So there as well, any chosen reference doesn't add anything to subjectiveness, it is the procedure that matters.

There is also a reference called experience. When I visit an acoustic live concerts, or when I hear good audio equipment, there is one important aspect that can be observed. Things sound "acoustic", "stress-free" and without an electronic haze. My audio in my living room has this property, the Sennheiser HD650 has this property, the iPod 5G has this property. The 6G has not. It sounds electronic, whatever other electronic reference I take.

Whether that sound characteristic adds a positive flavour to (some) music is a personal opinion. Some people seem to like a crisp sound, esepecially when they play shut-in and muffled rock recordings, that require some crispness to add a bit of dynamics to the recording. I wouldn't mind such a mode of operation (I have plenty of these type recordings as well which I happen to like a lot), but it would be great to have it as an option, instead of as an obligation everywhere.

Marc

Look, Hifivoice, if you're fishing to pick a fight I'm not biting. Okay, I'll bite but at least I don't care enough about winning to lose too much sleep over this. I don't live here and I'm not going to write a disertation of my experiences with sound and audio or write a resume' as to prove whether I'm qualified. After this I probably will have nothing more to say on the subject.

I will say that your responses feel like you aren't "listening" to what I am saying. I feel like you are more interested in hearing what you have to say. You complained when I posted that the 6g sounds better than you claim, and then you complain when I bother to take the time to see if you are right and then validate some of what you said. Make up your mind. I actually emailed Apple earlier with your form letter about fixing the 6G iPod.

Your second line sounds like a strawman argument, seemingly with the intent to distract from the main issue via a debate over the usefulness of reference standards, by tossing in a idiotic example of a 78rpm reference instead of a CD player. I am not going down that line...

The "reference" can be a standard or fixed measure, of which you can use to decide whether my opinions of the variable being tested can be considered a valid observation or not (6G vs 5.5G) - stating how I feel about the reference allows you to more easily trust or not trust my qualitative subjective opionions about the issue being tested.

There is another way to use the reference. Applying some form of scientific method says "ask a question, make a hypothesis, and test your hypothesis, and form a conclusion". But, IF one is going to make subjective or qualitative assessments in their tests (as opposed to quantitative assessments) there is no way for anyone outside of the test to know how to weigh the value of what the reviewer/observer has said IF there is NO point of reference. So, I gave you one.

THIS IS IMPORTANT - LISTEN. If I say "x iPod is closer to the reference system (i.e. the goal) than y iPod", then it is more helpful to other people than "y iPod is not as good as x iPod". Because if x had tons of bass, no midrange and shrilly bright treble, and I like that sound the most - then I have just recommended the one that sounds the worst to your ears! But if you have an idea of how good my reference sounds, you have an idea of what my tastes in sound are like and whether we have the same likes or tastes in sound.

Similar to the issue, my wife LOVES the way her Bose wave radio sounds more than my Denon AV receiver with Polk Audio SDA CRS speakers and a good source. She could talk about the great bass, or "it sounds so big", but if you ask her the right questions you'll discover that she also thinks FM radio in her 2001 OEM car radio sounds just as good. At that point you might have an idea that the reviewer's/observer's opinions may not be the best ones to place your bets on. How do you know if the Bose is really any good after all knowing how she views the two references above?

So, I never said comparing the 5.5G to 6G iPods wasn't subjective. I did say that it was less subjective if I could compare the sound to something of known quality. I needed to provide a frame of reference as to what I think sounds good and what sound quality the players should aspire to reach. So, when I say the 5.5G is more accurate with x or y type of music, and the 6G is better with A or B type of music, then you will know that I have a better idea of what I think accurate should sound like because of my reference.

One last thing - if the only variable we are studying is the source (5.5G vs 6G) and (1) the program material is the same and (2) the headphones are the same, it matters less whether we used my Shure SE500's or Denon AH-C700 or HFI700 DVD or Ety ER6i's, as long as they are sensitive enough to be driven by the iPod and revealing enough for detail, and we don't change anything else except whether it was the 5.5G vs 6G that we observed. We used the Ultrasone HFI700 DVD due to IEM not being well suited to two people swapping out earphones and changing tips. We felt the 600ohm HD600 weren't well suited to being driven by the iPod, and the PX100 were not detailed enough.

I agree, some phones and sources will compliment each other better than others, and maybe it is possible that x DAP with y headphones will sound the same as A DAP with B headphones, but that with different headphones the results could change and A DAP with y headphones could sound even better while x DAP with B headphones sounds worse - that isn't what I was testing for. Too many variables doesn't lend to a concrete conclusion.

Capiche?

Okay, good night and thanks for the effort to do the quantitative part of testing everything. Just don't assume others out there aren't capable of qualitative testing without a full resume'. I've done what I think are fair reviews of the iBasso D1, another on PenguinAmps vs Seaber CMoy bass boost, and another on volume attentuators. None of those are Placebo Results (as someone else put it) just because I don't have electronic measurements to back them up. There are things out there with rocky frequency curves that sound better than some that are flat, etc...

Hi HeadphoneAddict,

Obviously I've touched a sensitive topic, and you felt it as a personal attach... This wasn't my intention.

Extending the amount of devices to create an opinion in a wider context is perfectly valid. I do value everybody's personal preference regarding particular devices. When somebody prefers the 6G above the 5G, or device XYZ above any iPod, that's perfectly fine. But whatever device you choose as a reference in such a comparison, is an arbirtrary choice or based on personal preference. It only extends the context, and doesn't make a comparison "more valid", that was my point.

The comparison of the 6G with the 5G serves two purposes:
- Apple applied different engineering to them, proven by audible and measurable differences
- A lot of people consider replacing their 5G for a 6G.

When I discovered faulty behavior of the 6Gs' sound (an electronic veil/zizz, lack of 3D imaging), and I could support this behaviour by measurements, , this is beyond the scope of personal preference, and indepent of whatever reference device one would put next to it.

Whether one likes or prefers the sound of a 6G is a completely different topic. I prefer old recordings of Ella Fitzgerald playing on an old tube radio, knowing that the sound is full of artifacts.

Ken, that is a good deal! Man I only wished I had the dough!

Probably something everybody already knows, if so sorry. I found this this morning at iPodLounge...

"iPod classic tests reveal audio problems

Newly released audio measurements comparing the iPod classic to a fifth-generation iPod suggest problems with the newer iPod’s Cirrus Logic audio codec. Having initiated a discussion in Apple’s iPod classic forums, Marc Heijligers writes, “The measurements show is that the iPod Classic indeed has an uplift in treble, and its timing response is incorrect.” According to Heijigers, the new Cirrus Logic audio codec chip, which Roth Capital’s Jay Srivatsa says has replaced a chip from Wolfson Microelectronics inside the iPod classic, misaligns the arrival of treble detail relative to mids and bass, causing audio from the classic to lack “spatial information and a certain timbre.” Heijligers suggests that Apple may be able to fix the problem through a firmware update."

Well now that's its more publicly know apple may consider really looking into a fix if its possible

What if Marc H. is actually a head-fier and read this thread and posted the thoughts/findings & opinions of posters here. It would be like giving weight to a finding or opinion via duplicate posting on two well respected communities. Real funny.

But if anyone thinks I doubt the two are separate findings - no need to do so- It only seemed the posts seemed to be so similar to the posts here-- upper treble, lack of 3-D/spatial, root cause: DAC.

No offense meant-- there are a lot of superior musicians, audio engineers, thinkers and businessmen on this thread-- so I defer.