• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Why is it when testing the difference between 2 DAC/AMPs it only becomes apparent after you have listed to One for a while?

john5220

Active Member
Joined
Nov 4, 2019
Messages
181
Likes
66
#1
So my Xonar DG is DAC/AMP A and my Liquid Spark / Topping D 30 we will call it DAC/AMP B
So we have A and B

If I listen to B for a while like an hour or more, and I switch back to A which is the sound card, the SOund card sounds like sh!t. But once I then start switching back and forth after listening to 7 second clips the difference starts to shrink to the point where I can barely tell the difference.

What is the scientific reasoning behind this?

What I notice when switching back to the Sound Card is the voice in this case Lana Del Rey, her voice sounds Tunnel Like as in she is singing inside a tunnel where as the D30 and Spark sounds epic clean as in a studio and you are right there in person. How does one explain this using science?
 

garbulky

Major Contributor
Joined
Feb 14, 2018
Messages
1,099
Likes
397
#3
So my Xonar DG is DAC/AMP A and my Liquid Spark / Topping D 30 we will call it DAC/AMP B
So we have A and B

If I listen to B for a while like an hour or more, and I switch back to A which is the sound card, the SOund card sounds like sh!t. But once I then start switching back and forth after listening to 7 second clips the difference starts to shrink to the point where I can barely tell the difference.

What is the scientific reasoning behind this?

What I notice when switching back to the Sound Card is the voice in this case Lana Del Rey, her voice sounds Tunnel Like as in she is singing inside a tunnel where as the D30 and Spark sounds epic clean as in a studio and you are right there in person. How does one explain this using science?
You noticed that eh? I have too. I imagine people will tell you that you imagined the diffference.
 
Joined
Nov 4, 2019
Messages
181
Likes
66
#4
You noticed that eh? I have too. I imagine people will tell you that you imagined the diffference.
I keep wondering why is this, in a blind test you would never hear the difference it all sounds identical. Yet if you listen to one source for an hour and then suddenly switch the difference is so huge then when you switch back and forth quickly the difference becomes 0.

Kinda like how Nasa Hubble telescope won't pick up something in interstellar space immediately but if you leave it just long enough suddenly it can spot something as it captures more and more light, creating an image of some sort.

But this strange phenomena isn't true for every song, it is quite selective when it comes to songs. There are songs you can spend forever listening to and when you switch you wouldn't notice a difference.

Offcourse my case is different to Audiofools on Head Fi, they will claim they can tell the difference between DACs, but in my case I am comparing difference between budget $30 sound card and a really top notch perfect scoring external DAC and AMP, yet it is so hard to notice differences in general everyday use.
 
Last edited:

SIY

Technical Expert
Technical Expert
Joined
Apr 6, 2018
Messages
3,226
Likes
5,996
Location
Phoenix, AZ
#6
I keep wondering why is this, in a blind test you would never hear the difference it all sounds identical. Yet if you listen to one source for an hour and then suddenly switch the difference is so huge then when you switch back and forth quickly the difference becomes 0.
Doing things blind and level-matched doesn't preclude you from listening to each selection for an hour and deciding if things changed or they didn't.

"If you can hear it without peeking, you can hear it. If you can't hear it without peeking, you can't hear it."
 

PaulD

Active Member
Joined
Jul 22, 2018
Messages
150
Likes
310
#7
Doing things blind and level-matched doesn't preclude you from listening to each selection for an hour and deciding if things changed or they didn't.

"If you can hear it without peeking, you can hear it. If you can't hear it without peeking, you can't hear it."
EXACTLY!!!

If you cannot hear it without peeking, you cannot hear it. Everything else is imagined.

Welcome to the world of cognitive biases and the flawed perceptions of humans. We all do it! Mostly it's fun to find out how and why we do it, then enjoy listening to some music (instead of obsessing about warmth/depth/detail/microdetail/cables/PRAAT blah blah blah, all of which 99% of the time just biases...)

BTW, I do not believe, read, or indulge in casual listening impressions, especially not my own, for exactly the reason that they are completely unreliable (and to me completely worthless). The only reliable listening tests are double-blind and level matched. I have found it highly instructive when I have been bothered to do them. Measurements capture more than can be heard, you can believe them.
 
Joined
Nov 4, 2019
Messages
181
Likes
66
#8
wow didn't know our own ears are so unreliable, I suppose it is just how we evolved after all.

So true, blind tests nobody can tell the difference that means the article from Toms Hardware was correct when they proved that there wasn't a difference in sound quality from a $2 DAC and a $2000 DAC
 
Joined
Oct 20, 2019
Messages
91
Likes
51
#9
wow didn't know our own ears are so unreliable, I suppose it is just how we evolved after all.

So true, blind tests nobody can tell the difference that means the article from Toms Hardware was correct when they proved that there wasn't a difference in sound quality from a $2 DAC and a $2000 DAC
Hearing didn’t evolve for accurate comparisons of audio equipment. It evolved to give us the ability to respond to threats and opportunities.
 
Joined
Jun 18, 2019
Messages
111
Likes
147
#11
See, we humans aren't very good at remembering what we hear. Especially when it comes to details in complex arrangements of sounds. So, when it comes to making comparisons between things related to audio and the reproduction of music, it's easy to convince yourself that you are hearing details in whatever you are currently listening to that weren't there in what you listened to before. The longer the duration between what you are listening to now and what you are comparing it to, the easier it is for your brain to be tricked into thinking things sound better now than before. On top of that, if you happen to know that one item in your comparison is more expensive and/or more highly-regarded than the other item being compared you can easily fall victim to expectation bias - your dumb brain wants to believe that the thing that is SUPPOSED to sound better really DOES sound better - especially if you happen to be the one who dropped coin for the more expensive piece of kit. The way to avoid these things is to eliminate bias and take measures to manage our difficulty with remembering details of what we hear. Thus, volume matched blind A/B/X testing...
 
Last edited:

garbulky

Major Contributor
Joined
Feb 14, 2018
Messages
1,099
Likes
397
#12
wow didn't know our own ears are so unreliable, I suppose it is just how we evolved after all.

So true, blind tests nobody can tell the difference that means the article from Toms Hardware was correct when they proved that there wasn't a difference in sound quality from a $2 DAC and a $2000 DAC
Ahh well....if that makes the $2 DAC sound better to ya! ;)
 

Blumlein 88

Major Contributor
Joined
Feb 23, 2016
Messages
7,261
Likes
7,993
#13
Stuff others have already told you. Match levels. Blind testing can be done every few seconds or hours. Up to you. You could create your own file composed of several music files which is an hour long. Have someone pick a DAC randomly and play it for you. Leave the room and have that person randomly either swap DACs or keep the same one. Listen another hour.

It has been found something like 30-40% of people will hear a difference if they think something has changed even when nothing has.

As for short or long listening sessions? Echoic memory is a short period of some few seconds when your short term memory stores the actual sensory input and it can be compared to current sensory input. After some time (maybe 15 seconds) that info goes through something like an MP3 lossy compression and is transferred to longer term memory. So after 15 seconds you don't have the actual data to compare. It has been altered and some of it lost.

https://en.wikipedia.org/wiki/Echoic_memory

So in long listening sessions you are using an MP3 memory to compare to current stimulus. Your mind however is easily biased in a myriad of ways related to all sorts of things not having to do with sound, but which might color you perception of sound. Even long term a large enough sound quality difference can be heard reliably, but short term is capable of better finer discrimination. Long term memory is sitting there and capable of being perturbed by many other things going on in your brain and environment.
 

solderdude

Major Contributor
Joined
Jul 21, 2018
Messages
3,375
Likes
5,953
Location
The Neverlands
#14
Why is it when testing the difference between 2 DAC/AMPs it only becomes apparent after you have listed to One for a while?
short answer: Because you are testing this sighted... you KNOW what amp is playing. You are just 'testing' in the wrong and non scientific way.
I know for certain that I have experienced this effect myself and fooled myself (unknowingly) 2 times only to find out months later.
 
Joined
Jul 27, 2019
Messages
82
Likes
62
Location
Germany
#15
When you play tennis you can not resolve the ball speed-wise. Instead, the brain constantly sees a single ball position and computes the trajectory of the ball and updates that again with a new visual.
We live in a projection of our environment as our brain computes it. Easy test: Have a deep dream and the alarm clock goes off. For a limited time, the clock’s signal becomes part of your now changed dream.
Listening to music while viewing it does the same: You hear a projection of your brain’s view of the instruments and their expected and possibly stored sound. That process compensates for hearing loss too.
This happens with pure audio too, only that the brain has so little cues now, just this sound alone ( and a view on the stereo gear...)
The brain works hard to project the sound to your inner ear that arrives at the outer one, convolving it with whatever experiences it has sound-wise.
After an hour or so, the brain gets exhausted. It may very well be, that it then wants to hear a different audio stream to change, ease or just have a new projection, or simply gets tired projecting known instrumental sound onto a boom box’s output. Or this boom box’s sound resembles the brains projection easily and one gets stuck with it.
 

Blumlein 88

Major Contributor
Joined
Feb 23, 2016
Messages
7,261
Likes
7,993
#16
When you play tennis you can not resolve the ball speed-wise. Instead, the brain constantly sees a single ball position and computes the trajectory of the ball and updates that again with a new visual.
We live in a projection of our environment as our brain computes it. Easy test: Have a deep dream and the alarm clock goes off. For a limited time, the clock’s signal becomes part of your now changed dream.
Listening to music while viewing it does the same: You hear a projection of your brain’s view of the instruments and their expected and possibly stored sound. That process compensates for hearing loss too.
This happens with pure audio too, only that the brain has so little cues now, just this sound alone ( and a view on the stereo gear...)
The brain works hard to project the sound to your inner ear that arrives at the outer one, convolving it with whatever experiences it has sound-wise.
After an hour or so, the brain gets exhausted. It may very well be, that it then wants to hear a different audio stream to change, ease or just have a new projection, or simply gets tired projecting known instrumental sound onto a boom box’s output. Or this boom box’s sound resembles the brains projection easily and one gets stuck with it.
Some ideas in your post are interesting.

Reminded me of reading the book, "The Inner Game of Tennis" which was something of Zen and the art of Tennis. Maybe we need that relaxed focus for music listening.
https://www.amazon.com/Inner-Game-Tennis-Classic-Performance/dp/0679778314
 

stereo coffee

Member
Manufacturer
Joined
Jan 2, 2019
Messages
59
Likes
22
#17
Like dipping ones toes in the pool and running away, there is little to be gained - from only assessing audio reproduction capability of commercially available equipment. That is someone else's understanding of what they thought was possible in times past - or maybe a method to test the market place as to its gullibility, for bad implementations - lets hope their outlook was not that shallow. The panther never lies !!

But begin building your own circuits, and it will dawn - or should dawn on you that the three ( or is it four ? ) transistor connection methods - and endless combinations of devices and characteristics of devices, have created an entirely new place to assess what is possible with audio reproduction.

As brief example what is the audio difference between a good op amp, and a also good but same device but parallel connected op amp ? - you are unlikely to ever to be able to buy a parallel connected op amp in shops- just toes is it ? or are you willing to experience the comparative DIY sea, that urges you to try. It's rather nice- once you are in.
 

solderdude

Major Contributor
Joined
Jul 21, 2018
Messages
3,375
Likes
5,953
Location
The Neverlands
#18
The panther never lies !!
When will the panther get to measure your LDR volume control ? :p

you are unlikely to ever to be able to buy a parallel connected op amp in shops
O2 and Magni Heresy are well known examples of paralleled op-amps
There are even speaker amps consisting of paralleled opamps.
I designed/built one about 30 years ago with driver IC's from Philips CD4 mechanism drivers. But ofcourse one cannot buy it in shops, the ones above you can.


Later designed/built a headphone amp using 4 opamp outputs in parallel (not a commercial product).

Also used this 'trick' in a G1217 amp later on.
 

stereo coffee

Member
Manufacturer
Joined
Jan 2, 2019
Messages
59
Likes
22
#19
When will the panther get to measure your LDR volume control ? :p



O2 and Magni Heresy are well known examples of paralleled op-amps
There are even speaker amps consisting of paralleled opamps.
I designed/built one about 30 years ago with driver IC's from Philips CD4 mechanism drivers. But ofcourse one cannot buy it in shops, the ones above you can.


Later designed/built a headphone amp using 4 opamp outputs in parallel (not a commercial product).

Also used this 'trick' in a G1217 amp later on.
Soon. Nice work with the parallel op amps, did it sound better than any other you could buy for equivalent money ? I am not a great fan of the 6172, 5534 and 2132. In preference suggest you try the opa2107, opa111 ( can ) and 2107 again
 

solderdude

Major Contributor
Joined
Jul 21, 2018
Messages
3,375
Likes
5,953
Location
The Neverlands
#20
So you can hear differences under controlled blind listening tests between the mentioned opamps in an audio application with just a few times gain ?
 
Top Bottom