[Headzone]

So in my opinion there is a big difference in how DAPs sound. plus the higher end models have better outputs.

 

[CraftyClown]

  So in my opinion there is a big difference in how DAPs sound. plus the higher end models have better outputs.

 
Can you clarify what you mean by better outputs?

 

[CraftyClown]

So carrying this topic on, I'm still quite curious about the sound quality differences between different DAPs, particularly as we are now seeing price differences ranging less than $100 to greater than $3000.
 
Let's just say for example that both our $100 DAP and our $3000 DAP measure ruler flat across the frequency range, even under load. In this case, what other factors could affect the SQ for better or worse?

 

[Ruben123]

So carrying this topic on, I'm still quite curious about the sound quality differences between different DAPs, particularly as we are now seeing price differences ranging less than $100 to greater than $3000.

Let's just say for example that both our $100 DAP and our $3000 DAP measure ruler flat across the frequency range, even under load. In this case, what other factors could affect the SQ for better or worse?

Your earphone, output impedance, amp power, EM interference noise

 

[CraftyClown]

Your earphone, output impedance, amp power, EM interference noise

 
Well let's take the earphones out of the equation, we'll presume we're using the same earphones for both DAPs and let's also take impedance out as we're presuming both DAPs are unaffected by the load of the earphones we're attaching.
 
So that just leaves amp power and EM noise. How would both of these affect the SQ of our DAPs?

 

[reginalb]

   
Well let's take the earphones out of the equation, we'll presume we're using the same earphones for both DAPs and let's also take impedance out as we're presuming both DAPs are unaffected by the load of the earphones we're attaching.
 
So that just leaves amp power and EM noise. How would both of these affect the SQ of our DAPs?

 
If you are using the same earphone, you can't take them or impedance out of the equation. Here is what one earphone does to 3 different sources
 
Here is an unloaded and mid-range impedance load on a Schiit Valhalla, pretty flat in both cases. 
 

 
And then give it a multi BA load at a very low impedance, it literally goes off the chart.
 

 
Hifiman HM-602, high impedance load in white, pretty normal until the sharp hifiman rolloff, but look at it with the multi-BA iem load (blue line), again, it goes nuts down low in the frequency response, same load that screws with the Valhalla.
 

 
And with a Schiit Fulla
 

 
So I'm using the same earphone, and notice in all cases, I get a very different output from the DAP source. (Edited because 2 of my sources aren't DAP's, but it's the same in principle). 
 
You can take the amp out of the equation more easily than taking out the transducers, those are always the most important thing. With an amp, make sure it's got enough juice, and that its output has sufficiently low impedance. Even Schiit, who doesn't make transducers, says that they're the most important part of the equation. Amplifiers and digital to analog conversion are settled, figured out. EMI can be an issue, especially in some phones with sensitive IEM's. 

 

[CraftyClown]

   
If you are using the same earphone, you can't take them or impedance out of the equation. Here is what one earphone does to 3 different sources
 
Here is an unloaded and mid-range impedance load on a Schiit Valhalla, pretty flat in both cases. 
 

 
And then give it a multi BA load at a very low impedance, it literally goes off the chart.
 

 
Hifiman HM-602, high impedance load in white, pretty normal until the sharp hifiman rolloff, but look at it with the multi-BA iem load (blue line), again, it goes nuts down low in the frequency response, same load that screws with the Valhalla.
 

 
And with a Schiit Fulla
 

 
So I'm using the same earphone, and notice in all cases, I get a very different output from the DAP source. (Edited because 2 of my sources aren't DAP's, but it's the same in principle). 
 
You can take the amp out of the equation more easily than taking out the transducers, those are always the most important thing. With an amp, make sure it's got enough juice, and that its output has sufficiently low impedance. Even Schiit, who doesn't make transducers, says that they're the most important part of the equation. Amplifiers and digital to analog conversion are settled, figured out. EMI can be an issue, especially in some phones with sensitive IEM's. 

 
 
What I meant was, let's say for arguments sake the DAPs we're discussing are both fairly unaffected by the multi BA load, so we completely take that out of the equation.
 
I'm trying to acertain what the other notable differences might be

 

[castleofargh]

alll of them ^_^.  what Regi is trying to say is that the headphone/dap relation is just that. you can't really remove one for the sake of the argument because then you pretty much remove most audio reasons to buy a specific DAP or amp.
on principle, a headphone will be(should be) the weak link in the audio system and as such, we build around the headphone to get the best we can out of it. making sure we have enough power is basically making sure that the headphone's load will be the limiter in the circuit at a given loudness. the impedance ratio is also there to ensure a good power efficiency and a nominal electrical damping for the coil. the signal to noise ratio alone doesn't tell you much, you need the headphone's sensitivity to be able to try guessing if the background noise might be audible or not once set at your usual loudness.
you're closing a circuit and it makes so much sense to study the behavior of a complete circuit where we know the load(headphone) we will use in practice.

 

[CraftyClown]

   
If you are using the same earphone, you can't take them or impedance out of the equation. Here is what one earphone does to 3 different sources
 
Here is an unloaded and mid-range impedance load on a Schiit Valhalla, pretty flat in both cases. 
 

 
And then give it a multi BA load at a very low impedance, it literally goes off the chart.
 

 
Hifiman HM-602, high impedance load in white, pretty normal until the sharp hifiman rolloff, but look at it with the multi-BA iem load (blue line), again, it goes nuts down low in the frequency response, same load that screws with the Valhalla.
 

 
And with a Schiit Fulla
 

 
So I'm using the same earphone, and notice in all cases, I get a very different output from the DAP source. (Edited because 2 of my sources aren't DAP's, but it's the same in principle). 
 
You can take the amp out of the equation more easily than taking out the transducers, those are always the most important thing. With an amp, make sure it's got enough juice, and that its output has sufficiently low impedance. Even Schiit, who doesn't make transducers, says that they're the most important part of the equation. Amplifiers and digital to analog conversion are settled, figured out. EMI can be an issue, especially in some phones with sensitive IEM's. 

 
 

  alll of them ^_^.  what Regi is trying to say is that the headphone/dap relation is just that. you can't really remove one for the sake of the argument because then you pretty much remove most audio reasons to buy a specific DAP or amp.
on principle, a headphone will be(should be) the weak link in the audio system and as such, we build around the headphone to get the best we can out of it. making sure we have enough power is basically making sure that the headphone's load will be the limiter in the circuit at a given loudness. the impedance ratio is also there to ensure a good power efficiency and a nominal electrical damping for the coil. the signal to noise ratio alone doesn't tell you much, you need the headphone's sensitivity to be able to try guessing if the background noise might be audible or not once set at your usual loudness.
you're closing a circuit and it makes so much sense to study the behavior of a complete circuit where we know the load(headphone) we will use in practice.

 
What you're both saying makes perfect sense of course and I'm certainly not ignoring the facts. What I'm trying to understand is how many other significant and audible variables might be factors when comparing a low end and high end amp.
 
Hypothetically let's say I take some measurements from both a $100 DAP and a $3000 DAP and I discover that both have a very flat Frequency response and both react exactly the same with various multi  BA loads. In this scenario, what would be the next comparison I might make, if accurate sound reproduction is my only real interest? 

 

[Ruben123]

   
 
 
What you're both saying makes perfect sense of course and I'm certainly not ignoring the facts. What I'm trying to understand is how many other significant and audible variables might be factors when comparing a low end and high end amp.
 
Hypothetically let's say I take some measurements from both a $100 DAP and a $3000 DAP and I discover that both have a very flat Frequency response and both react exactly the same with various multi  BA loads. In this scenario, what would be the next comparison I might make, if accurate sound reproduction is my only real interest? 

A blind test would help you further.

 

[CraftyClown]

 
A blind test would help you further.

 
Subjectively yes, but what about from a more objective point of view?

 

[Ruben123]

Subjectively yes, but what about from a more objective point of view?

I think it's quite objective if you could or could not hear a difference between amps with your eyes closed

 

[ClieOS]

I think it's quite objective if you could or could not hear a difference between amps with your eyes closed

 
Agree. If a blind test is carried out in near perfect condition, then it should be just about as valid as any objective test. However, the test is about one listener's ability to differentiate. To be more valid as an objective test that can be applied to most people, you will need a large scale blind test with many more listener / test subjects.
 
However, going back to @CraftyClown previous question - that is, if two different DAP, regardless of price, measured the same in all circumstances - then the logical conclusion is that they should sound the same in all circumstances. However, the tricky bit is that generally we are not taking about a 100% identical measurement in any and all circumstances, but only the we have two DAP with measurement below some level of human auditory limits - would we still agree that both will sound the same?... and what is the auditory standard / threshold that we should agree that, when measurements goes below such standard / threshold, that we will no longer be able to tell one DAP (or any source) from another? I don't think scientist have figured that one out yet.

 

[CraftyClown]

   
Agree. If a blind test is carried out in near perfect condition, then it should be just about as valid as any objective test. However, the test is about one listener's ability to differentiate. To be more valid as an objective test that can be applied to most people, you will need a large scale blind test with many more listener / test subjects.
 
However, going back to @CraftyClown previous question - that is, if two different DAP, regardless of price, measured the same in all circumstances - then the logical conclusion is that they should sound the same in all circumstances. However, the tricky bit is that generally we are not taking about a 100% identical measurement in any and all circumstances, but only the we have two DAP with measurement below some level of human auditory limits - would we still agree that both will sound the same?... and what is the auditory standard / threshold that we should agree that, when measurements goes below such standard / threshold, that we will no longer be able to tell one DAP (or any source) from another? I don't think scientist have figured that one out yet.

 
What I'm also trying to ascertain is whether there are any obvious measurements other than frequency response we could be making? 

 

[castleofargh]

most measurements are very conditional, so if those measured conditions are too far away from people using the device, the results lose their significance. still I get where you're going, so here are some specs I personally like to see. how significant they are is another story ^_^.
 
 
- a comprehensive signal to noise ratio. usually in audio I'd expect something like +4DBu(about 1.2V), or for many products, they just max out the device or use whatever nominal setting that looks the best and leave it at that. even for those who wish to go with +4DBu or another standard, several DAPs can't do 1.22V so the end result is a mess. I'd like to see SNR but with a clear standard or if for some reasons they can't follow it, the values used clearly stated along with the SNR.
I'd also love to see 2 or 3 different measures at different voltages, to see if the noise is stable or if it rises a lot with the gain. that could help to speculate a little(it's far from perfect) about audible noises using sensitive IEMs.
 
 
- as mentioned a few days ago, I'd love to have maximum power at 1khz 1%THD into a few loads. it's something we always get for amps, and DAPs have an amp section. so ... What?  I can't understand why it's ok to say nothing or give useless specs like "power: 25mw" without telling if it's per channel, if it's max power or max power at 1%THD, and no idea about the load used when measured.
 
 
- same thing for crosstalk, it's unimportant to me overall because the values measured are often below what I can notice in ABX, but as we're getting that spec all the time anyway, then I'd rather see the crosstalk into a 16ohm load. the unloaded crosstalk is utterly meaningless to me unless it's already so bad you can guess the DAP has a design problem.
 
- impedance output, even better would be impedance over frequency in a nice little graph. and if we're doing free stuff, why not a way to see if the impedance changes with the output of the DAP for some designs.
 
- you start with the axiom "2 DAPs have the same FR", so I guess that is already measured. we could show the FR when loaded, but also be sure to be at 16/44 to see the type of low pass implemented at that sample rate. I totally don't care unless it's leading to a significant FR  change around 16khz^_^, but others might care for ringing, time smearing, and other horror movie titles.
if there is a low freq roll off under load, I'd like to know the value of the caps, or a FR into a few other loads to show when the roll off can be regarded as a problem.
 
you could get an objective result from any and all measurements, but I guess for the most part I'm just looking for those dudes to do their job correctly. the rest is really a bonus to me.  I have some massive trust issues when the brand telling me how great and professional they are, can't even write down a number with the proper unit next to it, or change the nomenclature with each new product so you can't compare them directly(true story).