[Bahnhof Zoo]

Your conclusions don’t correlate with how compressed digital audio works. There is no dynamic compression involved in processing by the AAC codec. If the codec isn’t causing what you hear with your trusted ears, then there is another reason you are hearing dynamic compression. The most likely reasons for that are different mastering, and expectation bias. You know AAC is used a lot for portable audio and you hear the word compression, so your brain tells you it is compressed for portable use. The truth is that at a sufficient data rate, it sounds exactly like lossless or HD audio.

I’m personally gaining a ton of insight from your posts, but I don’t know that any amount of scientific evidence is going to change dalmonegrigs mind at this point. Lol

 

[bigshot]

Well sometimes the intended audience isn’t the person we’re talking to.

I’m just amazed how many people like this there are and how similar they all are. The must be stamping them out of a mold somewhere. But seriously, I think the rest of Head Fi encourages a kind of faux intellectualism. They spout model numbers and brand names like baseball stats, but they don’t have a clue about what they are going on about really means. They are like memorized routines.

 

[Bahnhof Zoo]

Well sometimes the intended audience isn’t the person we’re talking to.

Very good point

 

[Dalmonegrig]

I’m personally gaining a ton of insight from your posts, but I don’t know that any amount of scientific evidence is going to change dalmonegrigs mind at this point. Lol

I also adequately perceive information, but in this case, they are trying to convince me that I cannot hear what I really hear. This is already more like Orwell's story Animal Farm.

 

[Bahnhof Zoo]

I also adequately perceive information, but in this case, they are trying to convince me that I cannot hear what I really hear. This is already more like Orwell's story Animal Farm.

I don’t know that they’re disputing what you are hearing. I think, more so, they are stating that whatever differences you are, in fact, picking up on are for reasons other than codec type.

 

[Dalmonegrig]

I don’t know that they’re disputing what you are hearing. I think, more so, they are stating that whatever differences you are, in fact, picking up on are for reasons other than codec type.

When listening, only the codec changes, and as a result, the sound quality changes. A clear cause-and-effect relationship. All other variables do not change during my listening.

 

[angelom]

When listening, only the codec changes, and as a result, the sound quality changes. A clear cause-and-effect relationship. All other variables do not change during my listening.

Two or three people with A LOT more knowledge and experience of technical aspects of codecs, measurements, and audio in general than you already explaining to you that dynamic range is NOT affected by the difference in codecs, and explaining to you the more real and possible variables happening in case that what you’re hearing is reasonably close to reality. But you’re, again, choosing ignoring this valuable information.

This is reminding me of the person who is driving in the wrong side of the road but is insisting that, in fact, ALL the others people are driving in the wrong side of the road.

One of the possible variables, expectation bias, is very more strong AND real than many people imagine, and is a variable that is possibly the more difficult that a person will admitting that is happening.

 

[Dalmonegrig]

Well sometimes the intended audience isn’t the person we’re talking to.

I’m just amazed how many people like this there are and how similar they all are.

Again cliches and labels, instead of logical justifications.

 

[Dalmonegrig]

Two or three people with A LOT more knowledge and experience of technical aspects of codecs, measurements, and audio in general already explaining to you that dynamic range is NOT affected by the difference in codecs, and explaining to you the more real and possible variables happening in case that what you’re hearing is reasonably close to reality. But you’re, again, choosing ignoring this valuable information.

Did I miss something somewhere? Where is this useful information for me that gives me a clear and precise answer? Why do I hear a difference in sound quality when changing codec? I don't see the answer to this question?

 

[sander99]

Why do I hear a difference in sound quality when changing codec? I don't see the answer to this question?

A number of potential reasons:
1. It’s actually a different master or a different source of the same master.
2. Some sort of processing, such as loudness normalisation.
3. The internet, a server or your connection is busy and the bitrate has been stepped down.
4. There’s no actual difference in sound quality but you’re perceiving one due to perceptual/cognitive bias.

G

Again: The codecs don't cause dynamic compression. People sometimes mixup data compression with dynamic compression.

 

[bigshot]

I also adequately perceive information, but in this case, they are trying to convince me that I cannot hear what I really hear. This is already more like Orwell's story Animal Farm.

I think your hearing is perfectly normal. It’s your thinking process that could use some work. You’re leaping to conclusions, rejecting established facts, and denying that you have normal human frailties,

 

[castleofargh]

Did I miss something somewhere? Where is this useful information for me that gives me a clear and precise answer? Why do I hear a difference in sound quality when changing codec? I don't see the answer to this question?

There cannot be a clear and precise answer so long as we cannot exclude your brain tricking you as the cause of your feelings.
You asked if it is the only possibility, and it isn’t, but it’s one of them and thinking you really hear a change when fully aware of the codec setting, sadly that does not remove the possibility of expectation bias. A diagnostic about sound change should start by making sure it exists. It’s not the easiest thing to test but it’s a reasonable first step and for sure, one of the possibilities that should be taken seriously until it it disproved.

I would also add, you can set a change on your source but the headphone does something else. Like some sources have more codec options than the headphone but won’t tell you when it’s not accepted(they just fall back on a more universal codec while showing whatever you picked still highlighted in the selection).
Or if the quality of the connection is bad, the source can fall back on either a lower rate for the selected codec, or a different codec(and lower rate).

And back again to bias, there could be a difference in delay when using a certain codec that gives your brain another evidence of change, or a sound when the internal dac changes sample rate, which in turn could be enough to experience other differences in sound that don’t have to exist. Your brain only need a lead on what’s playing and the idea that something is really different somewhere, not necessarily how and where you feel it’s different.

It could be that the conversion between your file and some codecs are audible in some cases and not others.

It could be that you went full audiophile on your description and talked about dynamic and what not when it’s just not what you felt. Maybe you don’t even have a clear idea of what dynamic compression can sound like(people tend to bring that up for everything, from DACs to format resolutions, but what they describe is often something else and sometimes even the opposite of what dynamic compression does subjectively). This scenario could involve sound differences you’re really hearing because while fairly transparent, few codecs(if any) are entirely faultless under all conditions with all files.

It could be that the headphone messes up for a particular codec, it’s rare nowadays, but in the elite audiophile world, it’s often 20 years ago somewhere.

 

[KinGensai]

@Dalmonegrig
You remember how I had the idea that SBC was inferior to AptX innately? I tested that assumption by doing a double blind test using recordings of the same song using each codec at max bit rate, I can't tell a difference. That doesn't mean there can't be a reason codecs change audio quality because bit rate can be bottlenecked by your gear for whatever hardware or software reasons, so if one codec gives you trouble just use one that doesn't, the codec itself doesn't affect transparency much at all if it's performing at max bitrate. If you're satisfied with LDAC's stability in use (no crackling, not abrupt bitrate changes, no disconnections, etc) just use LDAC.

 

[Dalmonegrig]

AAC, sound quality is average. Overall impression of AAC sound quality, this recording has low dynamic range.

A difference in codec wouldn't change balances in the mix, and AAC has very little impact on dynamic range. In fact it shouldn't have any affect at all. File compression isn't the same as dynamic compression.

that dynamic range is NOT affected by the difference in codecs,

Again: The codecs don't cause dynamic compression. People sometimes mixup data compression with dynamic compression.

It could be that you went full audiophile on your description and talked about dynamic and what not when it’s just not what you felt. Maybe you don’t even have a clear idea of what dynamic compression can sound like(people tend to bring that up for everything, from DACs to format resolutions, but what they describe is often something else and sometimes even the opposite of what dynamic compression does subjectively). This scenario could involve sound differences you’re really hearing because while fairly transparent, few codecs(if any) are entirely faultless under all conditions with all files.

I understand correctly, the codecs don't cause dynamic compression, and therefore cannot influence the deterioration of the dynamic range of the recording.
And it is precisely because of this that “spears break” in our discussion?

 

[bigshot]

AAC at the data rates we're talking about is audibly transparent. It doesn't sound any different than lossless. It has no "sound" of its own. Other lossy codecs are the same. We can remove the specific description you made, but it won't change the outcome.

The thing with lossless codecs is that they are designed to remove sound you CAN'T hear. At very low data rates, the data stream may have trouble keeping up with rendering the sound cleanly. As the data rate goes up, it eventually reaches a point where it isn't removing any audible sound or introducing artifacts at all. You can only hear a difference at lower data rates. And the difference you hear isn't a "veil over the sound" or "overall dynamic compression"... It's artifacts- those digital gurgles and blurps you hear when the codec doesn't have enough bandwidth to reproduce the sound transparently. So what you hear is clean sound with an occasional digital glitch. Some codecs roll off high frequencies at very low data rates, but with AAC, you have to get down to 128 for that to start kicking in at an audible level.

So here is the problem you are having... You have decided that you can hear a difference. You haven't made any effort to eliminate the possibility that expectation bias or perceptual error is creating the difference you hear. You are describing a particular kind of degradation to the sound that the AAC codec is incapable of creating. You're also sourcing the files you're comparing from different places without knowing if they come from the same mastering. What should this indicate to you? It should indicate that the chances are good that what you are hearing isn't the fault of the codec... it is error due to bias or the normal fallibility of human hearing. Or the two samples you have been comparing aren't taken from the same master and they actually were *intended* to sound different.

We've told you this over and over and you haven't listened. Now you're trying to backtrack and remove the clue that proves that your listening comparison is flawed. You want us to give you some other reason that you can hear a difference. Well, no. Your stubbornness just indicates more that this is expectation bias. If you REALLY wanted to know the truth, you wouldn't say things like "I only trust my ears." You would make an effort to eliminate bias and perceptual error by doing a line level matched, direct A/B switched, blind listening test with multiple trials averaged, and you would make an effort to understand how digital audio and compression codecs actually work. Until you do that, you're going to keep getting the same responses from us.

Blind test or it doesn't count. Sorry. That's just the way it is.