[Samueru Sama]

Very useful information, thank you for that. My onboard audio from both laptop and pc have very bad hiss. What would cause that?

So the multimeter would produce a perfectly objective datum and, if my volume is even slightly higher on one it will give the impression of greater dynamic range over the other. Am I correct in my understanding?

I doubt there would be too much of a difference between votages with S6 Edge + and Edge, I would think there would be a difference between EU and the rest of the world Samsung phones in general because of EU phones being volume capped.

 
 
Do you hear hiss with the HD650? Hiss is usually an issue with sensitive headphones, it really needs to be terrible for it to be perceptible in headphones like the HD650, If you hear it with the 650s that would mean that noise is higher than 65 uVrms.  What do you mean with greater dynamic range?
 
Huge amounts of noise can be due to groundloops (which are common issues on computers), also a bad decoupling from the power supply and/or lack of RF filters, also computers suffer from the fact that there's non that I'm aware of that has analog volume control, all of then adjust volume by reducing the signal amplitude at the DAC, there's a problem with that, it means that the output stage is constantly working at "100%" with all the noise from the DAC and johnson noise.
 
Lets say that the DAC+Lp filter max outputs 1 Vrms and has a fixed noise of 30 uVrms, that's tons of hiss with sensitive IEM's. However that gives a DR of 90 dB, you wont hear it at all if the volume is at max (1 Vrms) but obviously you can't do that with sensitive headphones, it will fry them if the thing is actually able to output 1 Vrms into low impedance loads, and also you will go deaf, so you have to reduce the amplitude down to 0.1 Vrms.
 
However since there's no analog volume control, the fixed noise is still 30 uVrms, And DR is now 70 dB. Had there been a potentiometer before the final stage, that noise would have been reduced down to 3 uVrms, that's complete silence for most sensitive IEMs without anything playing, obviously you now have to take the fixed noise from the final stage in consideration.
 
What most do is to raised the output impedance so that the noise amplitude is greatly reduce with sensitive headphones, and yet there are cases where you can hear hiss from the thing.
 
A slight difference in volume and non proper sync can greatly change your perception, also knowing which device is which. Were you completely unaware of which device was playing in your blind test?
 
Have you tried to ABX the first mega link? That's a galaxy Ace driving a 80 Ohm load at 0.2 Vrms, why 0.2 Vrms? Because more clips the signal. THAT'S RIGHT, the **** can't even output more than 0.2 Vrms without clipping, that's a utterly terrible hardware in that phone and yet, I'm not able to ABX vs the original file.

 

[fsi22]

   
 
Do you hear hiss with the HD650? Hiss is usually an issue with sensitive headphones, it really needs to be terrible for it to be perceptible in headphones like the HD650, If you hear it with the 650s that would mean that noise is higher than 65 uVrms.  What do you mean with greater dynamic range?
 
Huge amounts of noise can be due to groundloops (which are common issues on computers), also a bad decoupling from the power supply and/or lack of RF filters, also computers suffer from the fact that there's non that I'm aware of that has analog volume control, all of then adjust volume by reducing the signal amplitude at the DAC, there's a problem with that, it means that the output stage is constantly working at "100%" with all the noise from the DAC and johnson noise.
 
Lets say that the DAC+Lp filter max outputs 1 Vrms and has a fixed noise of 30 uVrms, that's tons of hiss with sensitive IEM's. However that gives a DR of 90 dB, you wont hear it at all if the volume is at max (1 Vrms) but obviously you can't do that with sensitive headphones, it will fry them if the thing is actually able to output 1 Vrms into low impedance loads, and also you will go deaf, so you have to reduce the amplitude down to 0.1 Vrms.
 
However since there's no analog volume control, the fixed noise is still 30 uVrms, And DR is now 70 dB. Had there been a potentiometer before the final stage, that noise would have been reduced down to 3 uVrms, that's complete silence for most sensitive IEMs without anything playing, obviously you now have to take the fixed noise from the final stage in consideration.
 
What most do is to raised the output impedance so that the noise amplitude is greatly reduce with sensitive headphones, and yet there are cases where you can hear hiss from the thing.
 
A slight difference in volume and non proper sync can greatly change your perception, also knowing which device is which. Were you completely unaware of which device was playing in your blind test?
 
Have you tried to ABX the first mega link? That's a galaxy Ace driving a 80 Ohm load at 0.2 Vrms, why 0.2 Vrms? Because more clips the signal. THAT'S RIGHT, the **** can't even output more than 0.2 Vrms without clipping, that's a utterly terrible hardware in that phone and yet, I'm not able to ABX vs the original file.

​Yeah with the hd650, it's more annoying on the laptop,it was a hiss that I would hear even with me just putting volume on 1, I use the odac on it now, so its not an issue anymore.
 
By dynamic range I'm borrowing a term we use in photography and video calibration. It is taking your brightest (loudest in audio terms) and darkest (softest) value and dividing it. eg. My tv has a contrast ratio of 500:1 and my monitor 3000:1  , both set at the same maximum brightness level of around 40cdm but the monitor goes closer to black in a dark scene than the tv so it creates the perception of a greater range of colours and tones (dynamic range) , even if it's slightly more our eyes percieve a greater sense of clarity, vividness, depth etc and without colorimeter it is not possible to accurately understand why.
 
I had my assistant aka poor wife do the cable swapping when I tried the phone and odac, if I set my audio level without a multimeter, my understanding is you are saying is the same as trying to eyeball brightness in critical situations, will always skew it 1 way or the other. Sorry if that was overcomplicated.
 
I did the test, results were.
 
foo_abx 2.0.2 report
foobar2000 v1.3.13
2016-11-26 15:51:31
File A: Test-01.flac
SHA1: de3eaf8773cafb2a23a8bb852d230936346e1d08
File B: Test-02.flac
SHA1: 2231512d913520f9b603ac79a44a7bc5ab6538ff
Output:
DS : Primary Sound Driver
Crossfading: NO
15:51:31 : Test started.
15:53:35 : 01/01
15:54:05 : 01/02
15:54:30 : 02/03
15:54:56 : 03/04
15:55:29 : 03/05
15:56:02 : 04/06
15:56:15 : 05/07
15:56:30 : 06/08
15:56:50 : 06/09
15:57:24 : 07/10
15:57:46 : 07/11
15:58:20 : 08/12
15:58:31 : 09/13
15:58:41 : 09/14
15:58:55 : 09/15
15:59:16 : 10/16
15:59:16 : Test finished.
 ----------
Total: 10/16
Probability that you were guessing: 22.7%
 -- signature --
c4802bcdc1901402add472bfe55e78672277bab6
 
 
Thank you for all the info, will have to read it a few times to digest it all.