[SilverEars]

  I don't think you're going to get much argument in Sound Science by saying that DAPs are audibly transparent. Unless there is something seriously wrong with their design and manufacture, that's certainly true. The same goes for CD players, SACD players and blu-ray players. Most computers intended for use as music sources as well. All players should be able to perform well enough that they are audibly transparent. When you can go out and buy a $40 cheapo DVD player and it performs to those specs, it isn't out of line to expect that from a fancy DAP designed specifically for listening to music.
 
As for headphone impedance matching... that is something you are going to need to pay attention to when you buy headphones. Some headphones require amping to perform properly and some don't. But that is irrelevant, because the measure of a player itself is usually made through line out, not the headphone out. The line out shows what the player itself is capable of. Matching with headphones depends on the headphones.

iphone 5 doesn't have a line-out.  Why would you measure to see how it performs with headphones to a line-out?  

 

[SilverEars]

   
1>
I'm always wary of "good reviews" saying such inconsistent things as "...all devises sound the same... ... there isn't much difference..." 
Either they sound the same and there isn't any difference (at all) or there isn't much difference and they don't sound the same. 
 
2>
When was this review written?  If the machine says numbers are too close between a 2004 nano and a 2014 iP5 for anyone to tell the difference, not only this 50K audio Analyzer is as useless as a toaster but the experiment itself is highly incompetent, which may explain why Mr Kenrockwell is trying to sell it for 10K (!!!) Hopefully, his review is just a bit dusty...

So basically, they measure below certain thresholds, so therefore they sound the same.  So he is implying you can hear with measurements. Over simplification.  If he can create sound with those graphs and measured values I would believe him.  

 

 

[bigshot]

  iphone 5 doesn't have a line-out.  Why would you measure to see how it performs with headphones to a line-out?  

 
Yes it kinda does. The headphone output is basically line level with an attenuation volume control.

 

[bigshot]

  If the machine says numbers are too close between a 2004 nano and a 2014 iP5 for anyone to tell the difference, not only this 50K audio Analyzer is as useless as a toaster

 
You have great faith in the quality of your own test. Could there have been an area you didn't control well enough when you did yours?
 
Line level matched? Direct A/B switched with no gap of time between? Blind comparison?

 

[bigshot]

  So basically, they measure below certain thresholds, so therefore they sound the same.

 
If the thresholds he's referring to are the thresholds of human perception, I'd say that is self evident.

 

[Roly1650]

[COLOR=0000FF]1>[/COLOR]
I'm always wary of "good reviews" saying such inconsistent things as "...all devises sound the same... ... there isn't much difference..." 
Either they sound the same and there isn't any difference (at all) or there isn't much difference and they don't sound the same. 

[COLOR=FF0000]2>[/COLOR]
When was this review written?  If the machine says numbers are too close between a 2004 nano and a 2014 iP5 for anyone to tell the difference, not only this 50K audio Analyzer is as useless as a toaster but the experiment itself is highly incompetent, which may explain why Mr Kenrockwell is trying to sell it for 10K (!!!) Hopefully, his review is just a bit dusty...

1> If the devices are audibly transparent they sound the same, see BIGSHOTS post directly above yours. Two devices can measure differently but both can still be audibly transparent. It's just impossible to have degrees of transparency. Nitpicking the language used doesn't invalidate the conclusion.

2> And the above may also be true of both the 2004 Nano and the 2014 iPhone 5, I haven't seen any test results for the Nano. What do your measurement show? Saying that doesn't automatically make the audio analyzer as useless as a toaster and/or the tester incompetent. And I really can't comment on the second hand value of a used piece of test equipment or the motives for selling, that would be impossible for anyone but the owner to know.

Again without wishing to be rude go look at the date of the test for yourself......

 

[SilverEars]

   
If the thresholds are the thresholds of human perception, I'd say that is self evident.

When SS devices distort they clip, so it's audible, these measurements are well below clipping, besides that do they explain what we are hearing or how the headphones respond?  It's meaningless to say based on this data they all sound the same.  I mean finding the point where they clip is trivial.

 

[bigshot]

Someone does a casual comparison in their own home noting subjective impressions about what they think it sounds like. Someone else does a much more rigorous test, complete with professional test equipment and very precise measurements. So since the rigorous test doesn't back up the casual comparison, it logically follows that the professional test equipment must be junk... yeah, right.
 
There is a problem with approaching things this way. You should be looking for evidence to figure out what the truth of the matter is, not grabbing at straws to back up your preconceived notions. The goal here isn't to be right at all costs. It's to figure out if there is a audible benefit between different pieces of equipment. Those measurements aren't even in the ballpark of audibility. Rockwell's measurements are so far below the threshold of transparency, it would be hard to imagine the degree of error in the testing procedure could possibly be broad enough to mistake transparent by an order of magnitude for audibly inaccurate.
 
Sorry Tympan. Go back and try again and check your results.

 

[SilverEars]

Base on the measured values can you say with certainty the characteristics of the sound coming from the headphones?  If not, how would you debunk the the impressions?  You know it's well below electrical translation of distortion, and output power is close to even throughout the spectrum at certain loads.  Can you say based on i5 measurements all i-products sound the same coming out of headphones?

 

[bigshot]

  Base on the measured values can you say with certainty the characteristics of the sound coming from the headphones?  If not, how would you debunk the the impressions?

 
I can say with certainty that the sound being put out of the iPhone is audibly identical to the content of the file the player is playing. How it sounds through headphones would depend on the headphones. I would attribute any incorrect impressions to being human error.

 

[Tympan]

   
Yes it kinda does. The headphone output is basically line level with an attenuation volume control.

No it doesn't "kinda does".
A headphone out and a line out are different. One has variable gain, the other is fixed. One is meant for iem/headphones, the other one for a preamplifier. Too low of a gain will affect dynamics and too high of a gain will create distortion. 
 

You have great faith in the quality of your own test. Could there have been an area you didn't control well enough when you did yours?
 
Line level matched? Direct A/B switched with no gap of time between? Blind comparison?

I trust my ears when I can hear noticeable differences. If I'm uncertain, I do blind tests. In this case, I didn't have to.
Again, there is no such thing as a Line out on the devices I've talked about (nano, iP4 and iP5) because they were intended for headphones and iems. 
It's fine if there is no difference to you when connected to a preamp. All I'm saying is that there are very audible differences when listening out of fairly neutral iems.

 

[SilverEars]

Arn't there lots of other parameters that can affect the audio output besides the power sweep and THD measurements at loads?

 

[bigshot]

  A headphone out and a line out are different. One has variable gain, the other is fixed.

 
I believe on recent iPhones and iPods, if you turn the volume all the way up, it is the same as line level. There isn't amplifying circuitry in the headphone out of the iPhone. The volume control is an attenuator instead. That's why headphones with lower sensitivity and higher impedance require amping to sound right.
 
I'd suggest that you might want to do some more controlled tests, because your impressions don't jibe with any measurements or controlled listening tests on iDevices that I've ever seen. Here in Sound Science we're allowed to tell you that just because you think your ears tell you something, it isn't necessarily true. Blind testing would help. My bet is that you didn't do level matching or set up direct A/B switching on your test either. I think you're going on a completely uncontrolled subjective impression.

 

[bigshot]

  Arn't there lots of other parameters that can affect the audio output besides the power sweep and THD measurements at loads?

 
Line out is line out.

 

[Tympan]

   
Wow! More inaudible than inaudible! That is a real trick! That tickles my funny bone!

Hehehe, funny!

 
I'm not talking about transparency in terms of background noise such as a hiss. Transparency by itself (with nothing audible) is called silence.
Transparency in relation to music playing depends on how the audio is presented. 
The quality of detail retrieval, transient, sustain, tonality... and whatever frequencies all play an important part of human perception as a whole. So assuming two DAPs are free of background noise or hiss, two sound presentations can sound much different in terms of transparency perception.
But let me use the word "resolution" instead.
The iP5 is more RESOLVING and precise sounding. More information is discernible, transient is tighter/faster and the separation between instruments is more precise... iP4 has longer sustain and resonance in the bass and mids, which sounds bolder and less precise.