It's not at all confusing once you understand what really goes on with an audio signal.
THD, frequency response, and S/N ratio are simply three of a long list of characteristics a signal can have.
They are the three which are most often mentioned for several reasons:
1) many people actually understand what they measure
2) they're relatively easy to measure
3) they're reasonably representative of "perceived sound quality" in
SIMPLE AMPLIFIER CIRCUITS4) they're also reasonably representative of overall performance in simple amplifiers (they tend to measure well in amplifiers that otherwise don't have problems; and poorly in amplifiers with other major problems)
When you apply "sharpening" to a picture in Photoshop it does
NOT make the picture brighter, or darker, or greener, or redder, or even sharper.
What it does is to alter certain very few specific pixels that tend to influence our perception (you might say it's "psycho-visual" in nature).
The sharpening process actually identifies places where contrasting pixels touch each other, and makes the darker pixel darker, and the lighter pixel lighter, using very specific parameters.
This produces a dark halo around the dark edge, and a bright halo around the bright edge; this makes edges "more obvious", which our brains interpret as "sharper".
The resulting modified picture
LOOKS sharper to humans, but technical analysis of the detail level shows no improvement.
(Feel free to decide for yourself whether this is a useful tool, or a trick, or simply a "value-neutral" way to improve the look of your artwork.)
Many audiophiles, being non-technical, fail to make this sort of distinction.
For example, no amplifier I have ever tested could
EVER affect "the rhythm and pace" of something.
Both of those terms properly (according to your favorite dictionary) describe the
TIME RELATIVE characteristics of the signal... and no analog amplifier circuit is capable of audibly slowing down or speeding up the timing of an audio signal passing through it.
Put an oscilloscope on that signal and you will surely find that it is at
EXACTLY the same frequency as before.... therefore, neither the rhythm nor the pace has been altered at all.
What is happening is that the amplifier is altering some other characteristic of the signal that we humans
INCORRECTLY perceive as a change in the timing.
In the case of DACs, the reverse is true.
The signal passing through a DAC is often altered in many subtle but significant ways... many of which involve timing.
However, most of those alterations are somewhat complex to measure, and
VERY complex to interpret.
If you look at the analog output of several different DACs with a variety of input test signals, you will see significant differences.
Many manufacturers and magazine reviewers publish certain of these characteristics - like "impulse response" - and those measurements are in fact different for Sabre DACs than for most others.
Unfortunately, even when looking directly at the images of those signal characteristics, it isn't always obvious what a given difference represents in terms of
SOUND.
What is happening is that Sabre DACs have certain differences from most other DACs in terms of how they handle some sorts of impulse signals.
Because we're talking about subtle differences, and because no current DAC is perfect in this context, it may be difficult to suggest which ones are "more correct".
(Most of us here at Emotiva agree that the DACs we've chosen to use produce an output that we perceive as being more accurate to the original than Sabre DACs.)
However, if you compare oscilloscope images of certain test signals, the differences themselves are relatively easy to see.
And there are certain commonalities in how they are perceived by the majority of human listeners.
When comparing a Sabre DAC to "an average DAC" from any of several other brands (with similar basic specs).....
- Some listeners fail to notice any significant difference
- Most listeners who notice a difference and
LIKE Sabre DACs describe them as sounding "more detailed" or "more revealing"
- Most listeners who notice a difference and
DISLIKE Sabre DACs describe them as sounding "etched" or "grainy" or "bright" or even "overly detailed"
Regardless of which group you agree with, it seems somewhat obvious that the same general characteristics are being described by both.
Note that the surrounding circuitry has a major effect on how a DAC chip will sound... and different products that use the Sabre DAC chips seem to exhibit this characteristic sound to different degrees.
(However, it would be accurate to say that, in most situations where someone does notice a difference, this is the way they describe it.)
So what you guys are describing is a very accurate DAC chip but you don't like it? In the other hand you like the very allegedly accurate Emotiva products? Yes I am confused...
