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Does a DAC make a giant difference? - Page 9

post #121 of 127

Im currently using the Xonar STX soundcard and to me, the sound from it is somehow better and clearer as compared to the onboard sound from my asus maximus 4 exreme motherboard.

So I believe it does make a difference. Thought the sound sig of the default op amps is not exactly to my liking so I'm still trying to figure out which op amps I should go with.

post #122 of 127
Quote:
Originally Posted by IEMCrazy View Post

What I've found often enough, based on DAC, is that I will get fatigued or bored more easily by the end of an album than by another.  So swapping a cable and saying "which DAC do you hear now?" I'd plainly state before starting that I wouldn't be able to tell the difference.  But after 40-70 minutes of listening, I bet I would find myself more fatigued of listening or more bored in the content with some useful consistency listening to brand X for most albums compared to brand Y.   And from that we could probably build an unusual ABX session spanning months.
People have done long-term ABX before, and it turns out it is far less reliable than short term testing to find differences. Our memories when it comes to sound quality are accurate for a couple seconds, at best.
Experiments have also been done with listening fatigue, but these have never result pointing towards one component being reliably more fatiguing than the other. A difference in perceived listening fatigue most likely is influenced more by psychological factors than it is by inaudible differences in sound quality.


Quote:
Different chips and different power topologies will have both different noise floors and different levels of precision/quantization-errors.  That's a measurable enough effect for instrumentation, and a cumulative effect for the brain.
Yes this is measurable, and for many decent DAC's this has been measured to be far below ambient noise or the noise of the record itself. This effectively means that many decent DAC's have no effect on the sound quality whatsoever, for all our flawed senses care they reproduce the music perfectly; i.e. the coloration of the DAC is fully inaudible. Most of the coloration (if not all) will always happen at the transducer (and room acoustics for speakers).


Quote:
I think the differences of a DAC work more in the subconcious thought of hearing than the overt differences of different speakers or amps or tubes.  There's subtle imperfect rounding errors that make it through that doesn't change the tonality in an obvious way but I think affect the ear or the brain or both in different ways. 
Sound quality, as expressed in distortion/noise and whatnot, has most likely very little effect on how the brain perceives it, given it has passed a certain point of inaudibility. This is not very difficult to reach at all with modern technology, and devices costing just a couple hundred dollars can easily get to this level.
Almost always perceived differences in quality of high end DAC's/amps are caused by psychological factors. If your brain somehow get the idea that one is different from the other, it will make you hear those differences. This is called expectation bias, and nobody in the entire world is immune to it; it is simply how the brain works.


--
And besides, why care about 0.0001% vs. 0.00000000001% distortion levels, when the headphones easily have more than 1% distortion at a range of frequencies.

Just my two cents.
Edited by Tilpo - 4/13/12 at 1:25pm
post #123 of 127
Quote:
Originally Posted by obzilla View Post

I've had half a dozen DACs now. Some sound impossibly similar. Some sound exceptionally different. It depends on the DACs and downstream chains being compared, but the short end of it is that the DAC is your source, and sources matter. Each one is the foundation (or secondary, the recording is the true foundation) of your chain, and it winds up leaving, to some extent or other, its signature on the final sound signature of the system.



I very much agree on this point (viz., the DAC being a source), and am therefore very much interested on who has the best discrete op amps in an offboard DAC, versus the National Semiconductor LM6172IN and LME91860NA and their integrated-circuit competition; some engineers have perfected the discrete-component route for parts of the chain from DAC to headset.  Among the variables routinely discussed in the high end are what headsets perform best with which amplifiers, as every transducer has some weakness, in terms of turning input current into output sound pressure across a wide spectrum of frequencies, which can be neutralized at the amplifier level.  My priority is the task of giving the amplifier/headset combination an accurate audio signal to work with.

post #124 of 127

DACs do indeed sound quite different - although, compared to, say, the difference between headphones,

you may or may not consider the differences important.

 

There are a whole bunch of issues which are being glossed over here.

 

The analog circuitry in the DAC certainly makes a difference, although the pervasive assumption that "discrete op amps"

are better than chip ones is not always true. There have also been studies that have shown that the better grade of op amp

chips don't sound especially different IF PROPERLY IMPLEMENTED. So, IN A GOOD DESIGN, changing the op amps won't

necessarily make a difference and, if it does, that difference may not be an improvement. Putting a "better" op amp into a circuit NOT designed for it may actually make things worse instead of better. Unfortunately, some op amps do sound noticeably bad

in certain types of designs, and, sadly, not all products are well designed. The point is that changing chips, or changing from

chips to discretes, may or may not be an improvement - depending on the overall design in which you are using them.

 

Simple specifications (like THD and S/N) usually don't tell much of a story for DACs because, for all except the poorest quality DACs, those numbers will be very good.... probably well below the limits of audibility. This is NOT, however, the same as saying that numbers don't matter, or claiming that there is some "intangible" involved. You just have to look at DIFFERENT "numbers". Things like "soundstage" and "depth" aren't intangible; we just don't have ways of measuring them directly. It's pretty obvious, for example, that soundstage has something to do with the phase relationships between various frequencies and the timing between them. (It's just not a simple and easily quantified measurement.)

 

One important "number" is jitter. Signal jitter definitely affects the way a DAC sounds, and DACs vary widely in their ability to eliminate jitter (or avoid being influenced by it). [It's also possible that extra jitter may artificially make the soundstage wider, which may be perceived as an improvement in some situations - with some music. If so, then eliminating that jitter, while more accurate, may NOT be perceived as an improvement.]

 

Another major differentiator between DACs is the performance of the digital and analog filters. Since those filters vary widely between DACs, and have a major effect on impulse response and phase accuracy, it's a fair bet that they have a lot to do with "soundstaging" and "transparency". Most DAC chips have digital filters built in, so it's reasonable to expect that units using a certain chip, and using the built-in filters that come with it, would have a similar characteristic sound - and may sound different than DACs using a different chip that has different filters. (Some chips have multiple choices, and some DACs use custom filters rather than the built-in ones. If you listen, even briefly, to a DAC that has switchable filters, you can cheerfully argue forever about which one is best, but it's pretty obvious that they are indeed subtly different.)

 

Headphones, being basically speakers, also have requirements in terms of being supplied with sufficient current and damping. Various studies have shown that many (but not all) headphones sound rather poor unless connected to an amplifier with a sufficiently low output impedance. Of course, again, this is something that can be measured and specified. Simple op amp based headphone amps, therefore, work very well with some headphones, and not well at all with others.

 

As has been noted, the differences between DACs are subtle enough that expectation bias is a major "risk" when comparing them. There are also enough variables that it can be difficult to analyze them all at once.

 

There ARE ways to isolate some of the variables, however.

 

For example, if you have a USB (and USB powered) DAC feeding your stereo, and you notice a lot of ground noise (the kind where you can "hear" what's on your computer screen chortling out of your speakers at low volume), try adding a simple "USB isolator" between the computer and the DAC. I'm NOT talking about an expensive USB-to-S/PDIF converter.... just a "USB isolator". Olimex and several other manufacturers sell them for about $50 (I bought one from these guys http://electronicsshop.dk). Most of them are based on the Analog Devices ADUM series isolator chips and should be equivalent. The one I tried totally eliminated the ground noise (and had no effect on anything else).

 

kLevkoff

 

Quote:
Originally Posted by bcschmerker4 View Post



I very much agree on this point (viz., the DAC being a source), and am therefore very much interested on who has the best discrete op amps in an offboard DAC, versus the National Semiconductor LM6172IN and LME91860NA and their integrated-circuit competition; some engineers have perfected the discrete-component route for parts of the chain from DAC to headset.  Among the variables routinely discussed in the high end are what headsets perform best with which amplifiers, as every transducer has some weakness, in terms of turning input current into output sound pressure across a wide spectrum of frequencies, which can be neutralized at the amplifier level.  My priority is the task of giving the amplifier/headset combination an accurate audio signal to work with.

post #125 of 127

Disregard, the Leckerton uses the Cirrus Logic CS4398 which is a flagship DAC.


Edited by theque - 11/21/12 at 1:27pm
post #126 of 127
Quote:
Originally Posted by IEMCrazy View Post

I don't trust my ear to ABX to test one DAC from another DAC with a few colored exceptions (DAC Magic for example is always an obvious component in a mix) and I don't doubt that many real ABX tests between DACs are inconclusive.

I'm not sure its fair to say there's no difference between DACs if they can't be reliably ABXed either though.  I know the same argument can be used for cables, but there's a little more basis for it on DACs.  What I've found often enough, based on DAC, is that I will get fatigued or bored more easily by the end of an album than by another.  So swapping a cable and saying "which DAC do you hear now?" I'd plainly state before starting that I wouldn't be able to tell the difference.  But after 40-70 minutes of listening, I bet I would find myself more fatigued of listening or more bored in the content with some useful consistency listening to brand X for most albums compared to brand Y.   And from that we could probably build an unusual ABX session spanning months. Different chips and different power topologies will have both different noise floors and different levels of precision/quantization-errors.  That's a measurable enough effect for instrumentation, and a cumulative effect for the brain.

I think the differences of a DAC work more in the subconcious thought of hearing than the overt differences of different speakers or amps or tubes.  There's subtle imperfect rounding errors that make it through that doesn't change the tonality in an obvious way but I think affect the ear or the brain or both in different ways. 

I would have to agree with the above - IMO there needs to be a back and forth audition between DAC 'A' and DAC 'B', over a period of time. There is a certain 'feel' that will become apparent over time, that will reveal the 'signature' of that component. I believe that any changes in a system are best auditioned in that manner. Quick ABX switches can give a clue, but that clue needs to be substantiated and verified over time.
post #127 of 127

To me a DAC is an extremely significant piece of gear as I listen to music via a PC or a Macbook and the quality of audio improves exponentially as long as the bits and frequencies improve. Although I would say once you get to 24 Bit 96Khz it is not at all different compared to the 192Khz frequency as long it is on 24 bits. I would love to hear 32 Bit Dac/ amps like the Fostex as I have no clue of how it sounds like with higher bit rate. 

 

All in all a DAC is very important for digital music consumer. I use Dr DAC DX2 dac with variable op-amps. 

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