[ab initio]

   
I find it strange that seemingly everyone in the audio community except those in this sub-forum accepts that DAPs can easily sound different.

 
I think you might be misunderstanding some of the arguments here a little. Nobody in this forum believes that DAPs cannot sound different. What many members of this subforum are skeptical of is that every DAP sounds different from every other DAP.
 
Here is the thing, you are asking questions about why your two DAPs sound different when you haven't yet demonstrated that they actually sound different. The members in this sub forum do not have your gear, so we cannot test and validate your assumption that the two DAPs sound different. Once you can reasonably demonstrate that the DAPs have a different sound signature, then we have eliminated a few of the possible answers to the original question of why the DAPs sound different.
 
Science is largely a game of process of elimination. The approach here is to answer your question "why do these DAPs sound different" by eliminating the various hypotheses.
 
Here, we can start a check list to narrow down the answer to your question:
 
Question:
Why do these DAPs sound different?
 
Possible answer: The volumes are set differently which is well known to cause perceived differences in sound quality
 
Possible answer: Sighted listening bias --- It is well known that if people see/feel/sense/think different equipment is playing music that they will tend to hear differences that don't actually exist
 
Possible answer: Differences in DAP--headphone interaction (things like damping factor, etc.)
 
Possible answer: Differences in analog circuitry in the headphone amp section (distortion, frequency response, etc)
 
Possible answer: Differences in the digital circuitry in the DAP (DAC, DSP, clock noise, etc.)
 
Possible answer: Differences in the DAPs suceptibility to RFI/EMI
 
Possible answer: Differences in the DAPs power supplies 
 
Possible answer: <any other hypotheses?>
 
 
Let's start eliminating things! The first two are the easiest to eliminate without requiring extensive research and an engineering degree
 
Cheers

 

[sonitus mirus]

Your list offers a lot of possibilities related to the DAP for differences. With so many variables to consider, how likely would it be that any 2 DAPs are alike?  

 

[bigshot]

You have to separate what is a difference in the DAP itself and what is simply perceptual or mismatched equipment. That's why I asked about a line level matched line out comparison that is A/B switched blind. That eliminates all of the other variables and tells you straight out if the DAP has a different sound.
 
I buy Apple DAPs. I've had eight different iPods, three iPhones and two iPads... they all were flat and clean and sounded identical. They all sound identical to my CD, DVD and blu-ray players too. If I bought something that sounded different, I would return it. I don't want to have to EQ each source separately. I want audible transparency.

 

[sonitus mirus]

Your experience is similar to my own, albeit with some different brands and some similar.  For any DAP, I look for line out or digital out capabilities.  

 

[Music Alchemist]

  I think you might be misunderstanding some of the arguments here a little. Nobody in this forum believes that DAPs cannot sound different. What many members of this subforum are skeptical of is that every DAP sounds different from every other DAP.
 
Here is the thing, you are asking questions about why your two DAPs sound different when you haven't yet demonstrated that they actually sound different. The members in this sub forum do not have your gear, so we cannot test and validate your assumption that the two DAPs sound different. Once you can reasonably demonstrate that the DAPs have a different sound signature, then we have eliminated a few of the possible answers to the original question of why the DAPs sound different.
 
Science is largely a game of process of elimination. The approach here is to answer your question "why do these DAPs sound different" by eliminating the various hypotheses.
 
Here, we can start a check list to narrow down the answer to your question:
 
Question:
Why do these DAPs sound different?
 
Possible answer: The volumes are set differently which is well known to cause perceived differences in sound quality
 
Possible answer: Sighted listening bias --- It is well known that if people see/feel/sense/think different equipment is playing music that they will tend to hear differences that don't actually exist
 
Possible answer: Differences in DAP--headphone interaction (things like damping factor, etc.)
 
Possible answer: Differences in analog circuitry in the headphone amp section (distortion, frequency response, etc)
 
Possible answer: Differences in the digital circuitry in the DAP (DAC, DSP, clock noise, etc.)
 
Possible answer: Differences in the DAPs suceptibility to RFI/EMI
 
Possible answer: Differences in the DAPs power supplies 
 
Possible answer: <any other hypotheses?>
 
Let's start eliminating things! The first two are the easiest to eliminate without requiring extensive research and an engineering degree
 
Cheers

 
Now this is more reasonable. I'm sure many DAPs do sound identical.
 
It's just that I don't have the resources to conduct proper tests in this situation. I don't even think the older player has a line out, for one. My first guess would be differences in the circuitry and the way it's designed in general.
 

  You have to separate what is a difference in the DAP itself and what is simply perceptual or mismatched equipment. That's why I asked about a line level matched line out comparison that is A/B switched blind. That eliminates all of the other variables and tells you straight out if the DAP has a different sound.
 
I buy Apple DAPs. I've had eight different iPods, three iPhones and two iPads... they all were flat and clean and sounded identical. They all sound identical to my CD, DVD and blu-ray players too. If I bought something that sounded different, I would return it. I don't want to have to EQ each source separately. I want audible transparency.

 
Refer to above. I don't think I can do this comparison in the first place with the older DAP.
 
I'm more open to believe that some Apple products sound the same, but here's the thing: hundreds (if not thousands) of people have published reports online about how the older iPods sound better than the new ones, particularly for the iPod Classic.
 
If you own multiple iPod Classics, have you done this test for them and published the results?
 
Since we're already on a tangent here, I might as well pose another question. I am considering getting the Sennheiser HD 800 and a budget amp/DAC like the JDS Labs O2+ODAC. It is said to be neutral and transparent. Would this be a good combo? Some people feel that the HD 800 is better paired with something less neutral, in order to help tame issues like perceived brightness and so on.

 

[bigshot]

  I'm more open to believe that some Apple products sound the same, but here's the thing: hundreds (if not thousands) of people have published reports online about how the older iPods sound better than the new ones, particularly for the iPod Classic. If you own multiple iPod Classics, have you done this test for them and published the results?

 
Yes. I compared the output of a lossless file using line out from my iPod to line level matched output from the original CD playing in a $900 CD player too. There was no difference. That is what "audibly transparent" means. It is good enough to sound exactly the same as everything else that is good enough. If the frequency response is flat, and the noise floor and distortion is below the threshold for audibility, it is audibly transparent. LOTS of equipment, expensive cheap and in-between fall into that category. All of my electronics do. If a player or amp doesn't meet those standards, there is probably something wrong with it.

 

[Music Alchemist]

  Yes. I compared the output of a lossless file using line out from my iPod to line level matched output from the original CD playing in a $900 CD player too. There was no difference. That is what "audibly transparent" means. It is good enough to sound exactly the same as everything else that is good enough. If the frequency response is flat, and the noise floor and distortion is below the threshold for audibility, it is audibly transparent. LOTS of equipment, expensive cheap and in-between fall into that category. All of my electronics do. If a player or amp doesn't meet those standards, there is probably something wrong with it.

 
Can you tell me which iPod Classics you compared, and how the comparisons were done?
 
What about aspects of audio other than the frequency response, noise floor, and distortion? Things like soundstage, imaging, decay, dynamics, definition, etc. contribute to transparency, do they not? (Then again, I'm using a different meaning here: transparent to the recording as opposed to transparent to other equipment.)
 
Tube amps have different frequency responses. Is something wrong with them?

 

 

[bigshot]

I compared the old white ones with four buttons at the top (2 of those), three of the ones that followed that with the classic design two 60s and an 80, and a 160GB classic. That's 6. I seem to remember having 8 but I can't remember what the other two were right now. I've had the first and third iPhone and iPad and compared them too. (or is my phone a 4? dunno)
 
Whenever I get a new piece of equipment, I check it against another piece of equipment I know is transparent. Line level matched direct A/B switched from the line out monitored through headphones and speakers. Not blind, but that really doesn't matter because I just need to know if they sound the same. It really isn't that hard.
 
Sound consists of frequencies measured in Hz, volume measured in dB and distortion measured as a percent (or as a dB). Strictly speaking, any other kind of deviation (timing errors, etc.) would show up as a form of distortion. But I don't measure any of this. I put two pieces of equipment next to each other at the same volume with the same recording and see if I can tell a difference between them. I haven't been able to detect any difference in players since I began in digital audio. Turntables, cartridges, microphones, speakers and headphones all sound different. But digital players and amps are completely identical in my experience.
 
Tube amps can have "euphonic" distortion or frequency response imbalances, but the good ones sound transparent just like solid state amps. My system is very carefully equalized, so I need to know that the response on all the sources is stone flat. Otherwise, I would have to EQ separately for each player and that would be chaos. I want to be able to play a song on my iPod and on my CD player and have them be the same. That way I correct the EQ once and it works for everything.

 

[castleofargh]

  Since we're already on a tangent here, I might as well pose another question. I am considering getting the Sennheiser HD 800 and a budget amp/DAC like the JDS Labs O2+ODAC. It is said to be neutral and transparent. Would this be a good combo? Some people feel that the HD 800 is better paired with something less neutral, in order to help tame issues like perceived brightness and so on.

for my own tastes with a flat source, I would have to remove up to 5DB!!!!! in the high mids and treble region of a HD800. I won't pretend that my tastes are pure neutral sound, but I can say with confidence that only a very small minority actually enjoys spending hours with a HD800 not EQed (one way or another). the headphone is bright, that's what it is and having good specs doesn't make it less bright.

 

[SilverEars]

 
Since we're already on a tangent here, I might as well pose another question. I am considering getting the Sennheiser HD 800 and a budget amp/DAC like the JDS Labs O2+ODAC. It is said to be neutral and transparent. Would this be a good combo? Some people feel that the HD 800 is better paired with something less neutral, in order to help tame issues like perceived brightness and so on.

The headphone is bright, and you will see the harsh treble bump on every FR graph you see all over the net so that hump is there.  It's significant enough that there is  mod out there to reduce the treble of the $1.5k headphone.  There seems to be plenty of amp rolling with the 800 and when people say they like a certain amp they will say treble is reduced and etc..  That in itself tells you about the nature of the 800, people roll expensive DACs and amps in hopes to tame the treble and get a more easily listenable experience.  Lot of deniers of it being a unpleasant phone to listen to with a solid state amp with genres other than classical or jazz.  classical or jazz are easy on that treble region, so therefor its not as unpleasant of an experience as other genres that lots of folks have collections music of.  To me it's obvious those genres doesn't touch upon the treble of the 800 so it doesn't bring out it's worst, but according to 800 users it's just tranparent or neutral and "garbage in garbage out" to rationalize the nature of the 800 which isn't really the case as they seem to be ignoring the obvious treble peak there and the fact that the quest of the right source is to basically get it to not sound bright or add body to the sound which the additional harmonics distortions of the tube amp can provide.  
 
I could not enjoy music much out of it, it does indeed resolve well, but it really should with the treble boost.  It's analytical because of it sounding bright and being light on the bass.  It's on the other extreme of the Audeze which I believe people call it's sound signature "organic" which I believe means dip at the early treble region, which is a contrast from the HD800.  I notice some members here have a phone that is analytical and having one that is more "musical" is having headphone that complement each other because the analytical isn't pleasant sounding with all genres, but the "musical"(which I think it probably has the "organic" nature) one should be easier on the ears for the genres that sustains the harsh trebles.  Also, I have noticed similarities in FR of what is called dark and oraganic in the treble area, but what is dark has lifted bass from what I understand.  If anybody has better idea of the way sound sig is talked about please provide your thoughts.  
 
Since it was tolerable with limited recordings, it would shift my music preference to audiophile tracks. Not enjoying music types you enjoy was a problem to me. After that experience, I realize that detail retrieval and high resolution comes at a price. 

 

[Music Alchemist]

  for my own tastes with a flat source, I would have to remove up to 5DB!!!!! in the high mids and treble region of a HD800. I won't pretend that my tastes are pure neutral sound, but I can say with confidence that only a very small minority actually enjoys spending hours with a HD800 not EQed (one way or another). the headphone is bright, that's what it is and having good specs doesn't make it less bright.

  The headphone is bright, and you will see the harsh treble bump on every FR graph you see all over the net so that hump is there.  It's significant enough that there is  mod out there to reduce the treble of the $1.5k headphone.  There seems to be plenty of amp rolling with the 800 and when people say they like a certain amp they will say treble is reduced and etc..  That in itself tells you about the nature of the 800, people roll expensive DACs and amps in hopes to tame the treble and get a more easily listenable experience.  Lot of deniers of it being a unpleasant phone to listen to with a solid state amp with genres other than classical or jazz.  classical or jazz are easy on that treble region, so therefor its not as unpleasant of an experience as other genres that lots of folks have collections music of.  To me it's obvious those genres doesn't touch upon the treble of the 800 so it doesn't bring out it's worst, but according to 800 users it's just tranparent or neutral and "garbage in garbage out" to rationalize the nature of the 800 which isn't really the case as they seem to be ignoring the obvious treble peak there and the fact that the quest of the right source is to basically get it to not sound bright.  
 
I could not enjoy music much out of it, it does indeed resolve well, but it really should with the treble boost.  It's analytical because of it sounding bright and being light on the bass.  It's on the other extreme of the Audeze which I believe people call it's sound signature "organic" which I believe means dip at the early treble region, which is a contrast from the HD800.  Have a phone that is analytical and having one that is more "musical" is having headphone that complement each other because the analytical isn't pleasant sounding with all genres, but the "musical"(which I think it probably has the "organic" nature) one should be easier on the ears for the genres that sustains the harsh trebles.  Also, I have noticed similarities in FR of what is called dark and oraganic in the treble area, but what is dark has lifted bass from what I understand.  If anybody has better idea of the way sound sig is talked about please provide your thoughts.  

 
I'll add planar magnetic and electrostatic headphones to my collection later, but right now, I want to pursue a neutral sound as close to the recording as possible, and have been talking with experienced individuals about solutions. Some tell me that instead of getting a colored amp and so on, it would be more cost-effective to merely use equalization with a neutral source. I doubt the upper mids and lower treble are as sibilant as my current headphones can be, at least. I'm also getting a custom mod for it.

 

[SilverEars]

Guys, we're drifting a bit from the real topic of why hard drives sound different. 

 

[castleofargh]

  Guys, we're drifting a bit from the real topic of why hard drives sound different. 

I think the OP must organize a world tour and send us both his drives so we can confirm the audible differences ^_^.

 

[wuwhere]

 
I think the OP must organize a world tour and send us both his drives so we can confirm the audible differences ^_^.

 

 

[trentrosa]

After reading all this I'm glad I'm into analog...