[ADUHF]

Is your closest achievable neural more neutral than my definition of neutral?
My plot of the Harman curve is impossible to achieve either, but can a brother gets his point across?

I'm not there yet, but I'll give you my best guess at the moment on the above question.

I use diffuse field btw, because it's easier to use those as a basis for comparison with the sound of actual loudspeakers in a room. So here is what the 2018 Harman Over-Ear target looks like with diffuse field compensation, as a starting point for this discussion...

I suppose it depends just how far off of neutral your headphones are to begin with. But fwiw, I seem to be finding curves that are a little closer to the actual behavior and characteristics of loudspeakers in a room (especially their directivity) a somewhat better model for a neutral sound than the above shape.

In broads strokes, the overall shape of the curve should be a downward slope toward the treble of about -10 to -15 dB in total. Which works out to approximately -1.0 to -1.5 dB per octave. So somewhat similar to the above curve. But perhaps with some of the following tweaks or adjustments...

There should be a somewhat flatter area or "plateau" between about 3.5 and 8.5 kHz. Some bumpiness is ok there though. Most of the better headphones will have a few small peaks or hills there, usually at the 3.5, 5.5-6.0, and 8k frequencies. Which is totally ok.

Less roll-off in the treble. Perhaps as little as only a few dB, or 5 dB by 20 Hz, instead of the rather pronounced roll-off in the higher frequencies shown above. I go by the levels of the peaks in the treble btw, rather than using some sort of average of the peaks and troughs there. Because there are typically large notches at around 10k, 15k and 20k. Those notches don't count toward what I'm talking about here. And need to remain intact.

A depression of at least a few dB or possibly more at around 2k. Imo, the depression in that area on the Harman curve is positioned a bit too high in frequency. So it's not really having quite the desired effect. (And is probably making the upper mids between 1.5k and 2k sound too bloated by comparison.) I'm still experimenting with just how deep and how broad this depression should be though. Because the optimal shape seems to vary a bit with different recordings. The directivity indices and sound power curves of loudspeakers may be a good guide here, since this correction is partly to compensate for the diminished dispersion at the crossover of the midrange and tweeter drivers in this range. This diminished dispersion will manifest as a dip in the sound-power curves, and as a small peak or bump in the directivity index of a speaker's spin-o-rama plot. More about this below.

The sub-bass should be on the order of 10 dB higher (give or take) than the somewhat flatter area in the upper-mids/low treble between 3.5 and 8.5k. (Audiophiles who prefer more mids and treble may prefer a bit less bass though. And "bassheads" may prefer a bit more.)

And instead of a fairly confined depression in the upper bass at around 200-250 Hz, there should probably be a very modest sag or smile in the overall shape of the curve from approximately the mid-bass to the somewhat flatter area in the upper mids/low treble. Which give the overall curve a subtle U-shape. (Plus a little roll-off or flattening out at the ends. And the dip at 2k.)

Hard to picture all of this in one's head. But it should become a bit clearer once I'm a little more confident on all this. And able to post a few plots of headphones with a similar response. The basic message though is room curve, with a dip at 2k. Maybe a little roll-off in the treble. Notches in treble left intact.

This applies mainly to Oratory's diffuse field plots btw. Since I haven't looked at this type of data from other sources. To see just the diffuse field data for the headphones, you have to select it from the drop-down list of "Target response" options. And also turn off the "Include raw" option, by selecting No there, to hide the headphones raw response.

You can also find the spinorama measurements for a number of loudspeakers here...

https://www.audiosciencereview.com/forum/index.php?pages/SpeakerTestData/

Use the scrollbar on the right side to scroll down to more speakers. And double-click on "Review & Measurements" to see the spinorama graphs for each speaker.

Although he doesn't really deal with the topic of headphones per se, this video by Floyd Toole (which is about an hour long) explains how the spinorama speaker data works. And the difference between the direct sound curves (which should always be fairly flat), the sound power curves which help to predict the speaker's in-room sound. And the directivity index curve.



The directivity index will be kind of a mirror image of the sound power, or room curve (which is actually calculated from the direct, early reflections and sound power curves). And it gives you an idea how even the dispersion of the speaker is across different frequencies. That's important because it effects how loud the speaker is at different frequencies when placed in room. Greater dispersion = more reflection from the walls & surfaces = greater loudness.

The directivity index curve turns this characteristic upside down though, and really shows you the areas where the response of the speaker is more highly directional. And less broadly dispersed. (Which is a bit confusing.) To put this into context though, the dispersion of a speaker is always the widest at the lower frequencies in the bass. And that's why it's always the lowest area on a directivity index curve. Because the speaker is least directional in that range. (That should make perfect sense to alot of speaker buffs. But it frankly took me awhile to grasp this concept.)

Another model I use for my headphone's response are the reference levels for home theaters, which include a 10 dB increase in the lower frequencies. There is a link in my sig which explains that in more detail.

Most of the better open-back headphones also follow a model roughly similar to what I have outlined above in the treble and midrange. And they only begin to divert from this below around 200 Hz in the bass, due to the physical limitations in their design. So they also follow a "room sound" analogy as well. You will find diffuse field plots for many of the popular open-backs in Oratory's graphing tool as well, so you can confirm this.

I am not sure which of the headphones on Oratory's graphs are the most accurate yet. But some of these mostly closed-back headphones might be in the general ballpark...

https://headphonedatabase.com/oratory?ids=72,210,68,36,11

Sennheiser HE-1

PSB M4U (ANC on) - maybe a bit too rolled off in the treble, and bit too bumpy in the bass.

Onkyo A800 - this is pretty well-extended in the bass for an open-back, and maybe also a bit too rolled off in the treble.

Hidition Viento - the response is a bit uneven in the upper mids and treble, but pretty good in the bass and lower mids.

Apple APM (Vocal - Moderate) - too depressed in the low treble, but otherwise fairly good.

https://headphonedatabase.com/oratory?ids=205,275,56,73,141

Beyerdynamic Custom One with (Velour 3/4 Bass) & (2/4 Bass) - probably not depressed enough around 2k, and a little bumpy in the bass, but otherwise pretty good.

Focal Radiance - probably not depressed enough around 2k, and too depressed around 4k, and too much of a bump in mid-bass, but in the ballpark generally.

AudioTechnica M40x - Too rolled off in the sub-bass, and possibly a tad too withdrawn and U-shaped in the mids versus the levels at 200 Hz and 8 kHz, but not too bad otherwise.

Audeze Mobius & Audeze Sine (Cipher Cable) - both are too withdrawn in the low treble, and maybe not quite depressed enough around 2k, but otherwise in the ballpark.

AKG K371 - Too depressed in the high treble and at 4k, and maybe not depressed enough at 2k, but otherwise in the ballpark

You can use the links above to also look at raw responses of these headphones versus the Harman target (and other compensation curves). Just select "Harman 2018" from the Target response pulldown menu.

 

[Edric Li]

I'm not there yet, but I'll give you my best guess at the moment on the above question.

I use diffuse field btw, because it's easier to use those as a basis for comparison with the sound of actual loudspeakers in a room. So here is what the 2018 Harman Over-Ear target looks like with diffuse field compensation, as a starting point for this discussion...



I suppose it depends just how far off of neutral your headphones are to begin with. But fwiw, I seem to be finding curves that are a little closer to the actual behavior and characteristics of loudspeakers in a room (including their directivity) a somewhat better model for a neutral sound than the above shape.

In broads strokes, the overall shape of the curve should be a downward slope toward the treble of about -10 to -15 dB in total. Which works out to approximately -1.0 to -1.5 dB per octave. So somewhat similar to the above curve. But perhaps with some of the following tweaks or adjustments...

There should be a somewhat flatter area or "plateau" between about 3.5 and 8.5 kHz. Some bumpiness is ok there though. Most of the better headphones will have a few small peaks or hills there, usually at the 3.5, 5.5-6.0, and 8k frequencies. Which is totally ok.

Less roll-off in the treble. Perhaps as little is only a few dB, or 5 dB by 20 Hz. I go by the levels of the peaks in the treble btw, rather than using some sort of average of the peaks and troughs there. Because there are typically large notches at around 10k, 15k and 20k. Those notches don't count toward what I'm talking about here. And need to remain intact.

A depression of at least a few dB or possibly more at around 2k. Imo, the depression in that area on the Harman curve is positioned a bit too high in frequency. So its not really having quite the desired effect. (And is probably making the upper mids between 1.5k and 2k sound too bloated by comparison.) I'm still experimenting with just how deep and how broad this depression should be though. Because the optimal shape seems to vary a bit with different recordings. The directivity indices and sound power curves of loudspeakers may be a good guide here, since this correction is partly to compensate for the diminished dispersion at the crossover of the midrange and tweeter drivers in this range. This diminished dispersion will manifest as a dip in the sound-power curves, and as a small peak or bump in the directivity index of a speaker's spin-o-rama plot. More about this below.

The sub-bass should be on the order of 10 dB higher (give or take) than the somewhat flatter area in the upper-mids/low treble between 3.5 and 8.5k. (Audiophiles who prefer more mids and treble may prefer it a bit lower though.)

And instead of a fairly confined depression in the upper bass at around 200-250 Hz, there should probably be a very modest sag or smile in the overall shape of the curve from approximately the mid-bass to the somewhat flatter area in the upper mids/low treble. Which give the overall curve a subtle U-shape. (Plus a little roll-off or flattening out at the ends. And the dip at 2k.)

Hard to picture all this one's head. But it should become a bit clearer once I'm a little more confident on all this. And able to post a few plots of headphones with a similar response. The basic message though is room/sound power curve, with an extra dip at 2k. Maybe a little roll-off in the treble. Notches in treble left intact.

This applies mainly to Oratory's diffuse field plots btw. Since I haven't looked at this type of data from other sources. To see just the diffuse field data for the headphones, you have to select it from the drop-down list of "Target response" options. And also turn off the "Include raw" option, by selecting No there, to hide the headphones raw response.

You can also find the spinorama measurements for a number of loudspeakers here...

https://www.audiosciencereview.com/forum/index.php?pages/SpeakerTestData/

Use the scrollbar on the right side to scroll down to more speakers. And click on "Review & Measurements" to see the spinorama graphs for each speaker.

Although he doesn't really deal with the topic of headphones per se, this video by Floyd Toole (which is about an hour long) explains how the spinorama speaker data works. And the difference between the direct sound curves (which should always be fairly flat), the sound power curves which predict the speaker's in-room sound. And the directivity index.



The directivity index will be kind of a mirror image of the sound power curve. And it gives you an idea how even the dispersion of the speaker is across different frequencies. That's important because it effects how loud the speaker is at different frequencies when placed in room. Greater dispersion = more reflection from the walls = greater loudness.

The directivity index turns this characteristic upside down though, and really shows you the areas where the response of the speaker is more highly directional. And less broadly dispersed. (Which is a bit confusing.) To put this into context though, the dispersion of a speaker is always the widest at the lower frequencies in the bass. And that's why it's always the lowest area on a directivity index curve. Because the speaker is least directional in that range. (That should make perfect sense to alot of speaker buffs. But it frankly took me awhile to grasp this concept.)

Another model I use for my headphones response are the Reference levels for home theaters, which include a 10 dB increase in the lower frequencies. There is a link in my sig which explains that in more detail.

Most of the better open-back headphones also follow a model roughly similar to what I have outlined above in the treble and midrange. And they only begin to divert from this below around 200 Hz in the bass, due to the physical limitations in their design. So they also follow a "room sound" analogy as well. You you will find diffuse field plots for many of the popular open-backs on Oratory's graphing tool as well, so you can confirm this.

I am not sure which of the headphones on Oratory's graphs are the most accurate yet. But some of these mostly closed-back headphones might be in the ballpark...



https://headphonedatabase.com/oratory?ids=72,210,68,36,11

Sennheiser HE-1

PSB M4U (ANC on) - maybe a bit too rolled off in the treble, and bit too bumpy in the bass

Onkyo A800 - this is pretty well-extended in the bass for an open-back, and maybe also a bit too rolled off in the treble

Hidition Viento - the response is a but uneven in the upper mids and treble, but pretty good in the bass and lower mids

Apple APM (Vocal -Moderate) - too depressed in the low treble, and maybe not quite rolled off enough in the treble, but I'm not totally sure about this.



https://headphonedatabase.com/oratory?ids=205,275,56,73,141

Beyerdynamic Custom One with (2/4 Bass) & (Velour 3/4 Bass) - probably not depressed enough around 2k, and a little bumpy in the bass, but otherwise pretty good

Focal Radiance - probably not depressed enough around 2k, and too depressed around 4k, and too much of a bump in mid-bass, but in the ballpark generally

AudioTechnica M40x - Too rolled off in the sub-bass, and maybe a tad too withdrawn and U-shaped in the mids versus the levels at 200 Hz and 8 kHz, but not too bad otherwise.

Audeze Sine (Cipher Cable) & Audeze Mobius - both are too withdrawn in the low treble, and maybe not quite depressed enough around 2k, but otherwise in the ballpark.

AKG K371 - Too depressed in the high treble and at 4k, and maybe not depressed enough at 2k, but otherwise in the ballpark

You can use the links above to also look at raw responses of these headphones versus the Harman target (and other compensation curves). Just select the "Harman 2018" from the Target response pulldown menu.

So normalize all the curves in my plot according to your neutral definition, is my deduction and conclusion still valid?

 

[ADUHF]

So normalize all the curves in my plot according to your neutral definition, is my deduction and conclusion still valid?

Imo, the response should maybe be a little smoother across the junction of the upper bass and lower mids. And there should be more of a subtle overall U-shape to the curve. I am still experimenting with all of this though, so I haven't reached any definitive conclusions on any of it yet.

I don't really see a good justification for the depression at around 200-250 Hz on the Harman curve though. That is near the cross-over of the midrange and woofer or sub-woofer drivers in a loudspeaker (though it's generally a bit lower down closer to 100 Hz). There seems to be less of a dispersion/directivity issue in the lower frequencies though. So I'm not sure why that depression is there. You will sometimes see features like that on some closed studio monitor headphones though, like my DT-770's for example. And some people prefer less bleed between the bass and lower mids. It is not my personal preference though.

Re the shelved up bass, there should definitely be a gradual (and possibly slightly exponential) rise going from the upper mids into the sub-bass imo, to better mimic the behavior of speakers in a room. The only area where open-backs tend to deviate significantly from this is below 200 Hz. Where they often don't have enough pressure to deliver the lower frequencies, due to their open design. Some warmer-sounding amps may help to compensate for some of that lost output in the lower registers though. And planars may stay more linear than dynamic headphones below the 200 Hz threshold.

 

[ADUHF]

This is what some of the above headphones look like on a raw plot versus the 2018 Harman target btw...

It's a bit harder to see the differences on a graph like this, but there is definitely a similar rise in the bass. The junction between the bass and lower mids is somewhat smoother though. This has not been a problem in my listening experience so far.

The headphones are also more withdrawn than the Harman target in the upper mids, in the vicinity of 2 kHz. And brighter in their peaks in the treble between 10 and 20 kHz. So those are some of the main differences.

There should also be obvious notches in the headphones' responses at around 9.5-10.5 kHz, 15 kHz and 20 kHz. That's also a bit hard to see on the above plot. But if you squint your eyes a bit, you can sort of see that there are some common features in those areas. Especially the rather pronounced notch at around 9.5k in the treble. And the notch at around 15k is also fairly visible...

These features are, of course, missing from the Harman target.

 

[478423]

My personal definition of basshead would be people the prefer the lower frequencies more than the mids or uppers, but I have seen a 2nd definition float around of that basshead means that they hate any frequencies above the lower end or that they only care about the lower end. I used both definitions because I have seen both used quite frequently, though my personal preference would be the 1st.

"Therefore, unless you hate midrange, especially lower-mids, where all the important stuff is happening in music of all kind, you should stay away from the Harman curve. QED."
Your meme also implies this by saying that bassheads think high bass, decreasing mids, and low treble is neutral. Of course, I dispute this because I know that is not neutral, but there's no point arguing this since we both agree that this is not neutral. Even though you didn't directly say that bassheads hate midrange, the very fact that this meme is aimed at bassheads and the quoted sentence above gives a strong implication of this.

But moving past this, what other curves would you prefer to see used as a comparison for neutral? Free field? Diffuse field? If we tried what your meme suggests and offer a perfectly straight line, you have to keep in mind the ear's and brain's amplification. The human ear is known to be more sensitive to some regions more than others, so a flat line will have the result of some regions appearing to be boosted while others recessed. I agree with you that more than Harman curve should be used, but I want to see your take.

 

[bigshot]

There should also be obvious notches in the headphones' responses at around 9.5-10.5 kHz, 15 kHz and 20 kHz.

Do you know what those frequencies actually sound like? Those frequencies represent the least important octave of human hearing. The only sound up that high is harmonics that are likely masked by lower octaves. I doubt any narrow dips that high would be audible at all with recorded music. You could only faintly hear it with test tones and it wouldn't be pleasant to listen to.

Charts don't mean anything without context to how human ears hear.

 

[71 dB]

Is it just my imagination working overtime, or am I sensing a bit of Harman curve humor in that comment?

Lets just say I use Sennheiser HD-598 + DIY headphone adapter with crossfeed. Whatever curve that system has I am happy with it. Sennheiser is not considered a "basshead" brand to my knowledge.

 

[sander99]

Another model I use for my headphone's response are the Reference Levels for home theaters, which include a 10 dB increase in the lower frequencies.

Are you by any chance referring to the 10 dB boost of the LFE channel? That is just because the LFE channel is on the distribution medium with 10 dB attenuation relative to the other channels. (Not always, and the playback system should switch the boost on or off accordingly.) So it is not something that really changes the frequency response.

 

[castleofargh]

Again, that target claims to satisfy the preference of most people. Everybody isn't most people. In practice, a lot of listeners aren't the perfect average guy with standard hearing and perfectly average dummy head. So whoever doesn't prefer that FR, maybe wait before you assume that everbody must also have your preference.



The bass discussion must consider:
Listening level (for the equal loudness curve thingy flattening progressively at higher SPL)

Music genre played.

Seal quality!!! This can have a huge impact on the low end. Measurements may not show the FR at our eardrum. Some will show the best placement, while others might chose to show an average of several measured positions. So, along with HRTF stuff impacting the mid and upper range and with it our impression of relative bass quantity, there is placement to consider for bass. Often we'll have lesser subs than on the graphs. And for some headphones, it will be the opposite. The rigidity of the dummy ear might forbid a good seal that our own ears can get.

And let's say personal taste.

 

[ADUHF]

Oh I nerfed the treble using EQ and did not use the stock earpads. I was hoping that this was a joke because I actually have seen on other places that people unironically think this would be a valid proof to diss bassheads. Especially since few mock trebleheads preferences.

But seriously, there really should be more research into other preferences besides Harman. Like if someone prefers less bass with more treble than neutral, are they less sensitive to upper frequencies? Would they be more sensitive to lower frequencies? Would there be a preference between upper treble and lower treble? Would this preference lead to different musical tastes versus someone that prefers neutral sound signatures or darker sound signatures? I do not have the answers to this, but I would be interested in this. If someone has papers that document this, please share!

Edit: You could also ask if said preferences lead to differences within the outer shape of the ear, the eardrum, the middle ear, the inner ear, or the process of conversion to electrical impulses. For example, do people that prefer higher quantities of bass than is neutral have some ear hair cells that are less sensitive to this? Could it be more of the process of the conversion to electrical signals instead?

This is a lot more productive than just saying that bassheads hate mids. Even assuming that all bassheads hate mids, you can frame this in a more testable way. Could it be that bassheads are the most sensitive to mids and as a result, avoid headphones which have mids as neutral or boosted compared to other frequencies? If this is the case, why? What part of the ear or nerves or other factors could cause a distinct preference towards the lower end that does not translate into mid or upper frequencies?

I’m only adding this because this is the Sound Science subforum. I’m not trying to be mean or ruin fun, but the subforum leans heavily scientific. When a meme is posted, especially one that deliberately uses faulty logic, it makes it rather difficult to make the discussion scientific or informative. Memes tend to invite shallow and unthoughtful feedback (I am looking at a particular site).

You'll find a little more info on some of the above in this topic (though you'll have to wade through alot of my theorizing on what "neutral" is there as well, to get to it)...

https://www.head-fi.org/threads/general-headphone-measurement-related-discussions.932495/

The Harman target is not just one curve btw. It contains curves for different subgroups, which are loosely divided into three categories, with varying levels of bass. The basshead subgroup has about a 3 to 6 dB greater rise in the bass than the generic 2018 Harman Over-Ear curve.

Imo, the preferences for more or less bass may actually have more to do with increased sensitivity in the upper mids for those with less hearing loss. Rather than decreased sensitivity in the lower frequencies. Others may have a different opinion on that though.

I think alot of so-called bassheads also like to listen at lower volumes. And so they may also need a bit more of a U- or L-shaped Fletcher-Munson effect, with more of a rise in the bass and to some extent also the treble to compensate for this. You may disagree with that though.

I would try lowering the volume of your headphones more in between the 1 to 3 kHz range though, especially around 2k, to see if that will also help to reduce some of your high frequency sensitivity. That area often seems to get artificially boosted (and harsher-sounding) in recordings, perhaps because of the reduced dispersion at the midrange-tweeter crossover of the loudspeakers used for mastering. And some headphones don't appear to adequately compensate for this.

It is also not unusual for recordings to be too punchy in the treble as well though. Some audio engineers (such as B. Katz) will suggest using a room response that is more attenuated in the treble for audio production. And one of the inevitable results of such a room response is likely to be a brighter and more punchy response in the treble in the recording. That seems to be by design in alot of cases. And it may work ok on some consumer equipment and speakers, where the extension in the treble is not as good.

If you are using headphones which have good extension in the treble though, then recordings which are more biased toward the treble will likely come across as being too strident.

 

[ADUHF]

Again, that target claims to satisfy the preference of most people. Everybody isn't most people. In practice, a lot of listeners aren't the perfect average guy with standard hearing and perfectly average dummy head. So whoever doesn't prefer that FR, maybe wait before you assume that everbody must also have your preference.



The bass discussion must consider:
Listening level (for the equal loudness curve thingy flattening progressively at higher SPL)

Music genre played.

Seal quality!!! This can have a huge impact on the low end. Measurements may not show the FR at our eardrum. Some will show the best placement, while others might chose to show an average of several measured positions. So, along with HRTF stuff impacting the mid and upper range and with it our impression of relative bass quantity, there is placement to consider for bass. Often we'll have lesser subs than on the graphs. And for some headphones, it will be the opposite. The rigidity of the dummy ear might forbid a good seal that our own ears can get.

And let's say personal taste.

Agree with all the above. My (cross-)post above basically just reiterates alot of what you're saying here.

 

[ADUHF]

Do you know what those frequencies actually sound like? Those frequencies represent the least important octave of human hearing. The only sound up that high is harmonics that are likely masked by lower octaves. I doubt any narrow dips that high would be audible at all with recorded music. You could only faintly hear it with test tones and it wouldn't be pleasant to listen to.

Charts don't mean anything without context to how human ears hear.

My hearing generally taps out somewhere in the mid-teens. So I can definitely hear things close to that range. And the notches in the treble, particularly around the 10k range can make a noticeable difference in the prominence of some sibilants... Which is why they should be left intact.

 

[ADUHF]

Lets just say I use Sennheiser HD-598 + DIY headphone adapter with crossfeed. Whatever curve that system has I am happy with it. Sennheiser is not considered a "basshead" brand to my knowledge.

The HD-598 has many of the features that I've described above. Including a rather pronounced dip around 2k. Some plateauing in the 3.5 to 8.5k range. A sizable notch at around 10 kHz. And the rise from the upper-mids into the bass. Since it is open-backed though, it can't maintain that rise into the sub-bass frequencies.

Several of the popular open-backed planar magnetic HiFiMans will also follow this same model in the treble and midrange, with a dip at 2k, plateau between 3.5 and 8.5k, and notches in the treble at 9.5 and 15k.

They will tend to flatten out more though in the sub-bass than many of the closed headphones.

Sennheiser used to make some bassier headphones as well, such as the HD-380 Pro.

https://www.stereophile.com/images/ifmeasure/SennheiserHD380Pro.pdf

Their Senn HE-1 e-stat also has a fairly nice rise in the bass...

Same dip at around 2k, and notches at 9.5 and 15k as the HFM's.

The notches in the treble appear to be a "feature" of Oratory's measurement rig btw. Rather than something within the headphones themselves.

 

[NA Blur]

Therefore, unless you hate midrange, especially lower-mids, where all the important stuff is happening in music of all kind, you should stay away from the Harman curve. QED.

A few questions:

Isn't the Harmon Curve referred to a "curve" in order to emphasize the gradual change in in amplitude over frequency? I mean, no where do I see a shelf technique used in the curve literature. To me it's basic correction for where the average ear is most sensitive. You dip that down, elevate the bass due to what has been found in listening trials as to what sounds better to most people. Some treble has been attenuated to prevent issues with where the ear is most sensitive such as the 1.5kHz, 3.5kHz, and 7kHz regions.

Now if you don't like the sound after mimicking the target curve so be it, but to generalize the the entire target curve process as a simple shelf in the frequency response is just plain uneducated.

Where did you get those images? Did you make them yourself?

 

[ADUHF]

Are you by any chance referring to the 10 dB boost of the LFE channel? That is just because the LFE channel is on the distribution medium with 10 dB attenuation relative to the other channels. (Not always, and the playback system should switch the boost on or off accordingly.) So it is not something that really changes the frequency response.

Yes. I am not that familiar with the processing used for surround sound systems, but this link states that the LFE channels should be calibrated 10 dB higher than all the other channels. And as a result, the sub-woofer should potentially be able to hit transient peaks as high as 115 dB (or possibly even higher when including bass-managed low-frequency content from the cross-overs of other channels), for reference level listening.

http://www.acousticfrontiers.com/2013314thx-reference-level/

2. Subwoofers must be capable of 115dB peaks

The low frequency effects channel is handled slightly differently and has a 10dB boost relative to the other channels. The maximum SPL that subwoofers could be asked to reproduce from the low frequency effects track is therefore 115dB at the listening position. In reality the situation is nearly always worse because the subwoofer must additionally reproduce bass managed* content from other channels. These challenges mean that multiple large subwoofers are typically needed to be able to properly reproduce the soundtrack as the director intended.

* Bass managed content is that from other speaker channels that has been diverted to the subwoofer. In home audio video receivers (AVRs) and pre-processors this is done by setting the speakers to small in the bass management menu and specifying a crossover frequency. With surround speakers, for example, an 80Hz crossover is typically used. This means that any content in the surround channels under 80Hz is essentially diverted to the subwoofer. For 5 bass managed speakers an additional 6dB and for 7 bass managed speakers an additional 8dB of output may be required from the subwoofer channel.

If you are suggesting that will have no effect on the frequency response of the setup, then you'll have to explain to me in a bit more detail why. Because the info above seems fairly unequivocal on these points.

It also seems to align pretty well with the approximately 10 dB gain in the sub-bass on many of the better closed-back headphones as well. (Viewed in diffuse field.) But perhaps that is just a coincidence. (?)