[bellsprout]

im pretty sure amps/dacs can be approximated to be time invariant 
Quote:

Yep, I agree - the more noise the worse it sounds. So then the problem becomes - how to measure noise? Doing it by taking an FFT (very popular method) sucks rather, its rather like trying to estimate traffic density at night by means of time exposure photography.

 

[Sapientiam]

And what do you mean by 'time invariant' here? If you mean the amount of noise put out does not change with the signal level then various DAC datasheets show you're mistaken.

 

[bellsprout]

no i mean Time invariant because if the output is only input dependent then any non linearities will be revealed by testing with the right input signal and u dont have to wait around to see it happen
Quote:

And what do you mean by 'time invariant' here? If you mean the amount of noise put out does not change with the signal level then various DAC datasheets show you're mistaken.

 

[Sapientiam]

Ah, like 'LTI' minus the L, I see. How does this help FFTs to see time-varying noise then?

 

[bellsprout]

what causes time varying noise? hopefully the power stage and op amp PSRR are such that the power isn't the primary source of noise

 

[Sapientiam]

Its signal-level dependent - so we could justifiably say that the input signal causes it. Looked in detail at any DAC datasheets?

 

[bellsprout]

so whats wrong with FFT?

 

[Sapientiam]

Nothing's wrong with FFT - just like nothing's wrong with a toothbrush. Both are tools which can be used inappropriately.

 

[bellsprout]

lols in light of the astounding new revelations we have ascertained the cause of bad things is people doin it wrong. hurrah for school!
 
btw i hope ODAC will be square

 

[kiteki]

Originally Posted by kiteki /img/forum/go_quote.gif
 

 
If you've got the cash it's not to hard to measure any parameter of a device's electrical output to insanely precise accuracy It's just a voltage that changes level over time. That's all there is too it.
 
Relating that data to perception is quite a bit more difficult but the experimental evidence indicates that the standard measurements are good predictors of audibility.

 
Sounds familiar.
 

 
Not really...
 

 
You broke down an audio (see: electrical) signal to it's most basic components, said that's all there is to it, and that we can measure it with "insane precision" (if you have the cash).
 
Likewise, I can break down humans to ATCG, say that's all there is to it, and that we can measure it with "insane precision" (if you have the cash).
 
Now, with my dNAScope I can compare a giraffe and a horse, and I'll find that their "signal" is 99.9999% the same, so then I'll either auto-fold that 0.0001% difference or raise the blinds.
 
It's true that if there's a suggested difference between horses and giraffes despite third party observations they're 99.9999% the same, then these "golden ears" that can tell the difference between them should be able to do so in an ABX or blind test.  So far so good！！  Now we run into the hazy and overcast weather of the human mind, if you "throw a blanket" over the horse and giraffe they suddenly appear the same！！
 
Case study - http://www.matrixhifi.com/ENG_contenedor_ppec.htm
 
Now let me link to why you thought (or were truly convinced) why you thought the horse and giraffe were different in the first place, it's called the psychovisual effect.
 
Case in point 1 - focus / steer / memory / expectation - http://www.youtube.com/watch?v=BYTlN6wjcvQ#t=1m27s "If you're listening for HF, you won't even hear the bass line" (translation ->) "If I focus on how tall the giraffe is, it'll appear tall, out of that big sea of data, I focused on tallness, so the next time I see the giraffe, I'll expect it to be tall, this is just how the human mind works, - likewise if I'm convinced the horse and giraffe will appear the same, I may steer myself that way".
 
Case in point 2 - The McGurk effect - http://www.youtube.com/watch?v=G-lN8vWm3m0 "It seems easy enough to seperate the sounds we hear, to the sights we see, but there is one illusion... ..." (translation ->) "When you're looking at a giraffe, you might actually be hearing a horse".
 
Case in point 3 - Human find filtering - (I don't have a video on this).  In short, our mind is constantly deleting a lot of audio information, such as room acoustics, you can test this with a microphone and listen to your own voice.  A lot of Asian people are constantly deleting the letter "R" when they hear it, since it's unnecessary, so they always hear L, it's true. (translation ->) "When you see a horse (R), it could actually be a giraffe (L).  Since your culture only has horses, your mind is deleting the unnecessary information".
 
 
Mild humour aside, is ABX reliable to find the differences?  In post #29 I explained why the Meyer & Moran study apparently failed, in statistics you set a margin of significance, let's say 5%, their study showed a statistical significance of 0.000001%, or apparently around 1% (according to stv014 in post #20), further... the results apparently indicated that "the recording engineers tested significantly better than other respondents", with statistical significance in a chi-squared test.  The editor of JAES accepted this and asked for further examination.  Further, here is one of Moran's conclusions in the sa-cd thread "[size=x-small]There is always the remote possibility that a different system or more finely attuned pair of ears would reveal a difference.[/size]".
 
In spite of the above it's on wiki and quoted in popular articles like this all the time.  The fact this particular study is quoted so often leads me to the theory there is a distinct lack of similar studies, at least in the English language.
 
So my personal viewpoint from the above data is that ABX does not have evidenced reliability.  Further reading here - http://www.avguide.com/forums/blind-listening-tests-are-flawed-editorial?page=2
 
So, my viewpoint on the ODAC is I support experimentation and direct comparisons to other DAC's.  I see no evidence supporting that it's transparent, only theory.  I also think the "$500 to charity" is a bit of a pool shark.  Anyway, even if someone believes it's 100% transparent, for whatever reason, aren't they interested in proving it's transparency versus lesser products?  Like the iBasso D-Zero, Leckerton UHA-4?  How come the ODAC+O2 is transparent and the Zero / -4 is not?  Where do you draw the line? 
 
Aside from all this, I've highlighted the reasons why I think it's a very positive DAC in other ways and suspect it has high capacity and sound-quality.

 

[estreeter]

I guess I shouldnt be surprised that this thread reached the point where its ready for Sound Science so quickly. I shall now summon the mods:
 
CABLE DBT -- CABLE DBT -- CABLE DBT -- CABLE DBT
TBD ELBAC -- TBD .....

 

[deadlylover]

Quote:

I guess I shouldnt be surprised that this thread reached the point where its ready for Sound Science so quickly. I shall now summon the mods:
 
CABLE DBT -- CABLE DBT -- CABLE DBT -- CABLE DBT
TBD ELBAC -- TBD .....

 
If a mod comes in here and yells AVADA KEDAVRA! for their 'moving the thread message', well, I'll donate a fiver to charity.

 

[kiteki]

 
If you want to talk philosophy...

 
Ok, after reading that, now your definition of objectivity (and likely others around here) is starting to make sense.  Zombies don't have qualia, I get it.  Still, I'm keeping this all within the realm of science and haven't made assertions like sound-quality/preference = subjective.

 

[kiteki]

I guess I shouldnt be surprised that this thread reached the point where its ready for Sound Science so quickly.

 
Well to be fair, it's a pre-announcement thread.  In the iBasso DX100 thread there were 200+ pages of discussion before it was released！！
 
I think the DX100 is a good candidate for blind-testing versus the ODAC+O2.  I hope that happens and I think a lot of DX100 listeners may be interested.  They both share a very similar DAC chip, I'm not clear on the differences.  Comparing any Hifiman DAP (for example) would be extremely easy, we're all familiar with the defunct Clip+ versus HM-801 discussion.

 

[bellsprout]

it was a good thread until all of u derailed it SMH