[bigshot]

We both agree. There's nothing for me to reply to about this. I just wonder why it is that no matter what I say, you read it as an insult and become argumentative- even agreeing with you. And it isn't just me. You argue with everyone. I wonder what I could say that you *wouldn't* turn into an argument?

 

[gregorio]

Are you sure you wrote that correctly?

More or less. I was referring to NOS DACs, which as far as I’m aware are the only type of DAC that often do not have a filter. A consequence of a filterless non-oversampling DAC is a frequency roll-off starting at around 2kHz (with 44.1k FS/s content).

Maybe it’s my use of the term “roll-off” that you thought was incorrect? Because the freq responses I’ve seen don’t actually roll “off”, they just reduce to around -3dB or so by 20kHz (and remain at that level, rather than rolling-off further).

G

 

[71 dB]

More or less. I was referring to NOS DACs, which as far as I’m aware are the only type of DAC that often do not have a filter. A consequence of a filterless non-oversampling DAC is a frequency roll-off starting at around 2kHz (with 44.1k FS/s content).

Maybe it’s my use of the term “roll-off” that you thought was incorrect? Because the freq responses I’ve seen don’t actually roll “off”, they just reduce to around -3dB or so by 20kHz (and remain at that level, rather than rolling-off further).

G

How do you define the "start" of roll-off? How much has the response dipped at 2 kHz to justify saying roll-off has started? 0.0001 dB? 0.07 dB? I'd say 0.5 dB is a reasonable criteria, but the "roll-off" hardly is 0.5 dB at 2 kHz if it is only 3 dB at 20 kHz.

 

[bigshot]

I don’t think he’s talking about anything that is particularly audible. Where it starts isn’t necessarily where you hear it. Where it hits -3dB is more significant than where the roll off starts. The difference between old school NOS DACs and oversampling ones is audible but not huge. I think we understand that. But I’m sure we’ll get an argument, no matter what.

 

[gregorio]

How do you define the "start" of roll-off?

Typically it’s where the reduction curve starts.

G

 

[71 dB]

Typically it’s where the reduction curve starts.

G

That would make sense if the reduction was precisely 0 dB up to 2 kHz and then "started" (the curve has a sharp knee). If you could post here a NOS DAC response having this behavior.

 

[gregorio]

That would make sense if the reduction was precisely 0 dB up to 2 kHz and then "started" (the curve has a sharp knee).

It makes sense if that’s where the reduction starts, regardless of how sharp the curve.

G

 

[71 dB]

It makes sense if that’s where the reduction starts, regardless of how sharp the curve.

G

Well the reduction goes all back to 0 Hz, so we need to set a threshold where it "starts". I googled some NOS DAC curves and the -0.5 dB frequency is about 8 kHz. The plot started at 5 kHz (about -0.2 dB) so at 2 kHz its perhaps -0.1 dB or so. Nothing to write home about if You ask me (above 8 kHz is another story).

 

[gregorio]

The plot started at 5 kHz (about -0.2 dB) so at 2 kHz its perhaps -0.1 dB or so. Nothing to write home about if You ask me (above 8 kHz is another story).

Agreed, the actual starting point is a bit vague with such a shallow slope, which is why I used the word “around” in my statement: “a frequency roll-off starting around 2kHz”!

I still think that’s a fair assertion. At what point (freq) the roll-off would be sufficient to be noticeable (ABX’able) is a different question and off the top of my head, I’m not sure how one could easily setup such a test with music recordings. At a guess, probably around 9-10kHz, maybe even 6-7kHz for some young adults with excellent hearing and some training. Certainly it’s well within the audible band though and I (and I’m sure others) have ABX’ed this type of roll-off using music recordings (with significant HF content).

G

 

[bigshot]

Here is a measurement. It really isn't particularly audible until the frequency is higher than most of us can hear anyway. The response of the transducers in the highest octave would probably muddle it up so it would be hard to discern too. In practice, it really doesn't matter. Like many things discussed in audiophile forums, it's more of a numbers thing than anything that you can clearly hear.

 

[71 dB]

Here is a measurement. It really isn't particularly audible until the frequency is higher than most of us can hear anyway. The response of the transducers in the highest octave would probably muddle it up so it would be hard to discern too. In practice, it really doesn't matter. Like many things discussed in audiophile forums, it's more of a numbers thing than anything that you can clearly hear.

Good post bigshot. I totally agree and the measurement you posted agrees with my "claim" that the -0.5 dB (which can be considered meaningfully "audible") point is about 8 kHz. I am afraid gregorio's talk about roll-off at 2 kHz is too dramatic and even misleading from the perspective of what is audible and what matters in respect of sound quality.

 

[bigshot]

I don't even think .5dB is meaningful at 8kHz. Maybe in the core frequencies or with tones, but up that high listening to music? Nope.

 

[gregorio]

Here is a measurement. It really isn't particularly audible until the frequency is higher than most of us can hear anyway.

Of course, I keep forgetting this is the bigshot forum rather than the sound science forum. What “most of us can hear” is therefore defined by bigshot, as is “meaningful” and therefore the fact this difference could be reliably identified in ABX tests is meaningless in this subforum.

The criticism often thrown at this subforum by deluded/disgruntled audiophiles, that it’s just a religious/cult subforum with no basis in science, which I had always considered false/“sour grapes”, gradually seems to be becoming more and more true. I’m interested in the science/facts and have no interest in a bigshot subforum falsely titled the Sound Science forum. It’s bad enough when the audiophile shills/trolls try to pervert the actual name of this subforum but when the regular/old time members start perverting it, what’s left apart from a bigshot/cult subforum?

G

 

[bigshot]

You work very hard at maintaining the reputation of this forum. You’re the poster child for sound science unreasonableness.

 

[gregorio]

You work very hard at maintaining the reputation of this forum.

Almost as hard as you work at trying to redefine it!!

G