[harry501501]

Thanks for the feedback. I do try take the placebo effect into consideration. So when reviewers say "X amp is bassier or bass light... Y has a bigger than usual soundstage.... Etc"... Is this nonsense?

 

[castleofargh]

Thanks for the feedback. I do try take the placebo effect into consideration. So when reviewers say "X amp is bassier or bass light... Y has a bigger than usual soundstage.... Etc"... Is this nonsense?

Who knows? A reviewer almost never bothers to use a setup with a switch to have near instantaneous comparison, and almost never does a proper volume matching before listening.
Of course actual blind tests to stop listening with their eyes is the ultimate rarity, so all in all, nobody knows for sure(certainly not the reviewer) if the impression is close enough to be considered right, or if it’s filled with made up stuff caused by a flawed test.
Sadly, reviewers and audiophiles tend to think all that is irrelevant to them, they ”know better”, they ”have experience”, as if knowing about biases magically made them go away. They’re so ignorant and/or so confident(usually goes hand in hand) that they really believe anything they feel to be objectively true about sound. It’s a level of delusion that always surprises me. Even more so when there is a constant reminder about objective and subjective stuff in audio forums. One would normally get a hint that maybe they’re not the same thing.

At some point it’s like basic psychology where someone tells you about a third person and you can see bits and pieces of the one talking to you based on what he/she has to say about that third person(you can find stuff about me right now ). IMO it’s the same with reviewers. they end up talking about themselves and their biases/beliefs a lot more than they think. After a few reviews hopefully you can start to see how often the price changes their mind, how often they favor an amp just because it’s written ”balanced” or ”class A” on the box.


Of course some changes can happen and the final frequency response could be altered(it’s usually the amp + a given headphone’s impedance causing a certain amount of change instead of the amp itself always doing that alone). And soundstage... well, as I said recently somewhere, it’s used to describe anything and everything, and different people are still likely to create a more or less different interpretation of space anyway. Almost anything audible, visible, or from any other senses, has the potential to alter that interpretation.
So they could be correct about the description with that headphone only, or they could say ”soundstage this and that” because one amp has more distortions(tube amps usually do and it could reach audible levels), or again, simply because one is a little louder. That would be real sound difference. Or it could be any sort of bias altering their interpretation of what they think is sound. Could also be that they have a deal with a brand.
It’s the uncertainty that ruins everything. More controls over the variables is the only proper way to increase confidence.

 

[gregorio]

I do try take the placebo effect into consideration.

Which generally will have no effect whatsoever on whether you actually experience it or not in a given situation. Unless of course one does more than just consider it and actually take steps to eliminate placebo, with a controlled test as castleofargh explained.

Placebo effect is a type of aural illusion, some illusions don’t work once you’re aware they’re just an illusion, others don’t work as well or change somewhat once you’re aware of them but in many cases, knowing about them and/or taking them into consideration makes absolutely no difference at all. The aforementioned Fletcher/Munson “curves” and balance appearing to change with volume is an example of the latter as is the stereo effect, and there are numerous others. Another example that surprises many people is the McGurk Effect, where our brain changes the word we think we’re hearing.

So when reviewers say "X amp is bassier or bass light... Y has a bigger than usual soundstage.... Etc"... Is this nonsense?

Typically “yes”, it’s complete nonsense! There are various reasons why we might perceive say a “bassier” sound where in fact there’s no difference at all. For example:
1. Placebo effect due to some bias or combination of biases, expectation and confirmation bias being the most common but there are others.
2. The Fletcher/Munson “curves” if the volume is different.
3. How we are listening can obviously make a difference. If for example we listen to exactly the same track twice, without changing anything at all but during one of those playbacks we focus our concentration on the bass, then we’ll obviously perceive more bass/bass detail.
4. Reducing the amount of mids and/or treble can be perceived as the inverse, increasing the bass. This is virtually always the case if the volume is adjusted to compensate for a loss of treble.

However, there are various reasons why the bass might actually change when we change amps (or anything else) but which have nothing to do with that change. For example:
1. Typically when changing amps or another system component, we’ll have to remove our HPs/IEMs to do so. A slightly different position when we replace/reposition them, just a millimetre or two, can have a relatively very large effect on the amount of bass impacting our ear drum.
2. A similar situation can occur with speakers, a different seating or head position of just a couple of inches or so can make a significant difference to the amount of bass/treble entering our ears, due to the effects of room acoustics.
3. User error is also a possibility. For example, some EQ or other setting inadvertently engaged on one of the amps.
4. An impedance mismatch due to certain HPs/IEMs/speakers, as castleofargh mentioned.

And lastly, the amp may actually be “bassier”, for example some tube amps might add distortion in the bass/mid bass region.

ALL the above possibilities (in both categories) are far more probable than the last possibility (that the amp is actually “bassier”), unless you’re comparing certain tube amps of course. The problem, as castleofargh stated, is that audiophiles and audiophile reviewers typically just jump straight to this last possibility and will usually either just completely ignore the existence of all the other more probable causes of their “bassier” perception or, consider some (or very rarely all) of them but then fail to adequately eliminate them or just discount them regardless.

If we wish to be factually accurate or logical/“scientific”, then obviously we cannot just jump to the last possibility without eliminating the other possibilities, especially as those other possibilities are more probable. Therein lies the issue; despite implying and often asserting otherwise, many audiophiles’/reviewers’ ONLY concern is their perception and their (typically fallacious) assumption/belief of what’s causing it. Being factually accurate, logical, scientific or even rational about the causes of their perceptions are at best a distant 2nd place but more commonly, of no concern/interest whatsoever! This is due to either: Ignorance, incapable of critical thinking, marketing BS, being antisocial/a sociopath (simply not caring about misleading others and/or being disingenuous/a liar) or a combination of some or all of the above.

G

 

[bigshot]

The placebo effect is an subconscious bias. By definition, taking it into consideration won't make any difference. It's not a conscious decision.

 

[redrol]

Im personally tuning IEMs. I take 3-4 weeks in general to hit the mark. My own ears are not infallible and I do often run music too loud. Time works it all out. Fresh ears in the morning are my favorite.

 

[ddlo]

The biggest error I see audiophiles make is thinking that if they are aware of expectation bias, they can consciously suppress it by just listening more carefully. That belief shows a fundamental misunderstanding of the placebo effect. You can't eliminate human nature by force of will.

very true! i myself couldn't identify between most decent dac/amp setups (much less cabling and other audio accessories like adaptors or mounts) in abx blind tests. however, as many knowledgeable headfiers here already mentioned, i often feel my cans/setup sounds different under different time/vol setting/wearing positions. while we hear differently and have different preferences on sound signature, it seems to me that the capability of most decent audio electronics have already exceeded the hearing capability of most listeners.

i can see the value of argument that personal enjoyment matters, no matter if there's actual/objective differences. i enjoy beautiful packing or finely finished surfaces of my audio gear too (which has no impact in audio performance at all). But it's quite wrong to spread the unfounded claims/myths clearly defying scientific evidences. i often was puzzled why a headphone needs over 10W or even stereo amps to power when the least efficient of them, as far as i know, is still rated at 83dB/mW or why an exotic power cable matters when the miles of length before it is only perfectly adequate industrial grade (including aluminum ones!)

it's quite weird that so many in this hobby insist their bias is "true" in the face of so many obvious and subjective scientific evidence suggesting otherwise. this sentiment seldom happens in other hobbies - i never saw mech watch lovers claimed the exemplary beautiful finishing or the double assembly process on ALS watches made any differences in terms of time keeping accuracy. i also never heard anyone claiming titanium leica rangfinder special editions have any difference in image quality over the normal ones. neither will shoe snobs claiming that bespoken JLL or saint crispin's is more comfortable than cheap nike sneakers. only audiophiles seem to insisting the minute details such as cable, materials of device enclosures, exotic mounts for electronic without moving parts, or even stickers could have profound impact to sound.

i myself see and value the effort and dedication putting into finely made products (even without any audible advantage) but it's misleading to claim audible improvement (in some cases) when there're clear scientific evidence against it (the claims that titanium/copper cases of DAP or hifi grade network switch or stickers that claim to bring "darker" background come to mind!). such obsession likely will cause more harm than good for this hobby.

just my 2cents

 

[gregorio]

Couldn’t agree more with practically everything you said, with the possible exception of this:

it's quite weird that so many in this hobby insist their bias is "true" in the face of so many obvious and subjective scientific evidence suggesting otherwise.

It’s not really so weird because the audiophile community is very closed. The vast majority of audiophiles are not “faced” with so much obvious scientific evidence. What they’re actually faced with is audiophile marketers, audiophile marketing and those who are reliant on it (such as reviewers and sites like this one), who do their best to make sure that audiophile consumers are not faced with the scientific evidence and who invent falsehoods to discredit the science if it is brought up.

G

 

[BobG55]

Couldn’t agree more with practically everything you said, with the possible exception of this:

It’s not really so weird because the audiophile community is very closed. The vast majority of audiophiles are not “faced” with so much obvious scientific evidence. What they’re actually faced with is audiophile marketers, audiophile marketing and those who are reliant on it (such as reviewers and sites like this one), who do their best to make sure that audiophile consumers are not faced with the scientific evidence and who invent falsehoods to discredit the science if it is brought up.

G

This Forum has saved me tons of money.

 

[LarsHP]

Question regarding how higher / lower amplifier output impedance alters the frequency response in low impedance EIMs.

I am (still) using the original UM Miracle, which has an official impedance of 15.9 Ohms. According to the experts / theory I have read, all HP amps with less than 2 Ohm output impedance should pair well with this CIEM, since the impact on the frequency response should be less than 1dB... (Factor 8 = 1dB, allegedly)

However, I have recently acquired FiiO M11 Plus Ltd (DAP) and compared it to my Hifiman HM901S w/ Balanced amp card (using single ended output on both). I also have the iBasso D7 Sidewinder USB-DAC for my PC.

The odd thing is that even though the manufacturers of all three units claims that the (single ended) headphone output has 1 Ohm (or less) of output impedance, the three sources appears to produce quite different frequency responses - at least subjectively. Using the UM Miracle, the FiiO seems to sound the most balanced, while the Hifiman sounds a bit dark (elevated lower mids and bass). The iBasso sounds just awfully dark. Heavy EQ'ing is needed to correct it. In fact, I have stopped using it with the Miracle for this reason.

I expect the stated HO output impedance in these sources must vary more than the specs implies (the FiiO and iBasso just can't both be around 1 Ohm when tonal balance difference is dramatic), but which of these three would then have the lowest, the medium and the highest output impedance? (I expect this to be determined by the impedance curve, but I don't think there is one available.)

 

[bigshot]

Are you volume matching? Most of the difference between different impedances is simple level differences, not response. And it's easy to interpret a level difference as sounding like a difference in response.

 

[castleofargh]

Question regarding how higher / lower amplifier output impedance alters the frequency response in low impedance EIMs.

I am (still) using the original UM Miracle, which has an official impedance of 15.9 Ohms. According to the experts / theory I have read, all HP amps with less than 2 Ohm output impedance should pair well with this CIEM, since the impact on the frequency response should be less than 1dB... (Factor 8 = 1dB, allegedly)

However, I have recently acquired FiiO M11 Plus Ltd (DAP) and compared it to my Hifiman HM901S w/ Balanced amp card (using single ended output on both). I also have the iBasso D7 Sidewinder USB-DAC for my PC.

The odd thing is that even though the manufacturers of all three units claims that the (single ended) headphone output has 1 Ohm (or less) of output impedance, the three sources appears to produce quite different frequency responses - at least subjectively. Using the UM Miracle, the FiiO seems to sound the most balanced, while the Hifiman sounds a bit dark (elevated lower mids and bass). The iBasso sounds just awfully dark. Heavy EQ'ing is needed to correct it. In fact, I have stopped using it with the Miracle for this reason.

I expect the stated HO output impedance in these sources must vary more than the specs implies (the FiiO and iBasso just can't both be around 1 Ohm when tonal balance difference is dramatic), but which of these three would then have the lowest, the medium and the highest output impedance? (I expect this to be determined by the impedance curve, but I don't think there is one available.)

As suggested there is the matter of listening to the same thing at the same volume level in a somewhat unbiased way.
But let's pretend that's not as much of a problem as it is and focus on gear. There could be sound differences for more reasons than just Impedance.
But let's pretend that's not the reason for your impression. Impedance could indeed affect the FR. How is tricky to know without actual measurements. I couldn't find an impedance graph online for that IEM, and that's a big issue to make any sort of guess as the IEM's impedance curve determines how much and where the FR would be affected by a different amp's impedance. The 15.9ohm spec is most likely the value measured at 1kHz, but with a multidriver IEM we know for sure that the value changes a lot between 20Hz and however high that IEM goes. If 15.9ohm was the lowest impedance point for the IEM in the audible range, then as you say, there shouldn't be more than 1dB difference between 2ohm and lower value amps. But if the IEM actually reaches, say 5ohm somewhere, now we could expect a bigger FR change in that frequency area when changing the same amps.

In case this is not annoying enough for you yet, consider that the impedance of the amp is in fact rarely flat over the entire audible range and can even change based on what you test it with. Hopefully this rarely matters outside of very low or very high frequencies and we can try to wishfully ignore it and stick to the given impedance number because it shouldn't do too much at an audible level. But it's there.

Long story short, find someone with that IEM who knows how to measure the impedance curve(maybe some of the reviewers who make measurements already have it?). Or get yourself like a 100Ohm resistor some wires, plugs and a soldering iron, and you can measure it yourself with Room Eq Wizard(free software).

For the short story long, you can check https://www.head-fi.org/threads/feedback-about-gears-stop-doing-it-wrong-impedance.866714/ where I show 2 IEMs and 4 "amps"(pretty extreme cases picked on purpose but not the worst that can happen) and how vastly different the FR impact can be depending on the IEM's own impedance curve.

 

[LarsHP]

Are you volume matching? Most of the difference between different impedances is simple level differences, not response. And it's easy to interpret a level difference as sounding like a difference in response.

Yes, I am volume matching, as well as I can, subjectively. However, the difference is larger than a little higher/lower volume should imply.

 

[bigshot]

It doesn’t take a lot of difference to significantly affect the sound. Are you getting under half a dB?

I’m assuming you are amping both of them to adjust levels. Are you doing a direct A/B switch between them so there’s no time between samples? That’s important too.

 

[LarsHP]

It doesn’t take a lot of difference to significantly affect the sound. Are you getting under half a dB?

I’m assuming you are amping both of them to adjust levels. Are you doing a direct A/B switch between them so there’s no time between samples? That’s important too.

I have both DAPs loaded with the same test tracks, so I just switch the plug from one player to the other. I have done this many times with various tracks, and the difference is obvious in all types of music, even without bass (like pure vocal music). The boosted lower end in the Hifiman is obvious enough that even if the level is slightly higher from the FiiO, the Hifiman will still sound darker. In other words, I can rule out the loudness effect (louder => perceived more low end).

 

[bigshot]

It could be the amp circuitry, not the DAC. You would need to use an amp to balance levels and guarantee identical impedance. You’re also not doing a blind test if you have to see to plug it in. There are many reasons they might sound different that have nothing to do with the DAC.

The things you need for a fair test, aside from an apples to apples comparison, is level matching, direct A/B switching and blind comparisons with multiple trials. I’m guessing you don’t have any of these.