[Inks]

Post 1: Intro​

Post 2: Rating System for: Packaging/Accessories - Build Quality - Comfort/Isolation ​

Post 3: Sound Evaluation​

Post 4: Frequency response graphs for newbies // Post 5: Glossary of used terms ​

Post 6: Useful Tools // Post 7: FAQs // Post 8: Technical Data​

 ​

[size=medium]Purpose[/size]​

 ​

  I am starting to evaluate or review IEMs (upcoming list below on my signature)  based on certain criteria I have put together.  The purpose of this thread is to provide an in-depth explanation of my evaluation process and to provide relevant knowledge needed. I am welcomed to constructive criticism in regards into how an aspect is evaluated and to any technical corrections needed.  
 
*I am currently working on putting everything together so it isn't done by any means*

 

[Inks]

*complete*​

Aspect 1: Packaging & Accessories ​

Aspect 2: Build Quality & Cable Ergonomics​

Aspect 3: Comfort & Isolation​

7 properties are rated in total​

 
These properties are divided by different aspects of the product and are rated individually (7 total) on a 5/5 rating system. 5 being the best that can be attained. Usually the ratings can be translated this way. 
 
5/5=Best in class. 
4/5=Outstanding or Great
3/5=Average
2/5=Below Average
1/5=Poor
0/5=Terrible or Nonexistent
 
I will provide an explanation for each rating given when the IEM is rated. 
 

 Packaging & Accessories ​

 ​

  When it comes to packaging, I pay attention to it's presentation and practicality. A well laid out packaging is both accessible and well laid out. The box should be easily opened without forceful tinkering or significant damage. In addition, eough space should be given to easily place everything back together in it's original state. When these factors are given one is allowed to get as close as one can get to it's original unopened state. Packaging obviously has to look nice, giving you the feeling that you're revealing a quality product. Packaging accounts for 1/5 of the rating.
 
  Accessories should be both practical and expansive. I give priority to quality tips in rating accessories as it allows users to save money from buying aftermarket ones. Quality tips are those that take differences in canal size in consideration and the acoustic needs of such IEM. Next I consider the need for a quality carrying case. IEMs are used for commuting, so manufacturers should take into account the need for a  quality shell that will protect them in a bag or luggage. A qualtiy case is hard and well enclosed, allowing maximum protection. I tend to prefer small carrying cases, but bigger cases serve their as well and no points will be deducted unless it's size is considerable. Besides these two main factors that dictate my rating of the included accessories, points are still given for lesser accessories, though to a much smaller extent. These "lesser" accessories include: 1/4 adapters, earguides, airline adapters, TRS/TRSS adapters, inline-volume controllers, filters, shirt clips, etc. While these very well serve their purposes I consider the shirt clip and (given the circumstance) filters to be the most important. While some may ignore the shirt clip altogether it can improve cable noise and stability in a portable setting, giving it a big role in everyday use. Filters are important because they tend to be costly and at times, hard to find, so it's important to have a good amount when they are needed. When it factors into the longevity of the IEM, while also being important to it's sound, my rating system gives filters a bigger role than lesser accessories. 
 

Build Quality & Cable Ergonomics ​

 ​

  When it comes to build quality, the cable is the most important factor as it will be the biggest factor dicating how long an IEM may last. Quality cables are those that can stand a good amount of friction due to it's build and protective strain reliefs, while maintaining good flexibility. Usually those IEMs with replacable cables will have a higher rating as it increases longevity significantly, though the quality of the stock cable will still factor in.  The shell should have good stability, placed together very well. A higher rating may be given to shells that are made of a material other than plastic, like metal, ceramic or wood.  Rating will be reduced if a dymamic driver based IEM produces driver flex [link]. I may mention and factor in the possibilty of having it modded to use a replacable cable pin or a simple recable [link]. This is a plus for it's build quality as it allows you to expand it's longevity. Points will be deducted if replacable filters or cables can't be bought. Consideration of deduction if the repleable filters or cables are of considerable costs. 
 
  Cable Ergonomics is how practical the cable of the IEM is in everyday use. Points are reduced for cables that are either too long or too short for commuting. The need for adapters will also be a negative factor, unless it serves an ergonomic purpose. An ergonomic cable minimizes tangle,  feels lightweight and flexible when worn. I will factor in the practicality of the mic and remote on the cable when it applies. Points are also reduced for a lack of a y-splitter. 
 
 Microphonics is simply the noise the cable produces as it moves around. Can be reduced or eliminated with an over-the-ear fit or a shirt clip. Lower the rating means, more possiblity of noise. An IEM with a high microphonics cable may have very little or no cable noise. 
 

Comfort & Isolation ​

 ​

  An IEM that is comfortable is both lightweight and well formed to the ear. Usually the smaller the IEM's shell is, the more comfortable it may be, vice-versa. The flexibilty of being worn both over-the-ear and straight down may grant the IEM a higher rating. 
 
  One of the main reasons for choosing an IEM will be for it's isolation properties, but sometimes a more passive isolation may be prefered. In additiont to the rating given, I will state how that isolation may translate to it's use. 4/5 or 5/5 ratings will be optimal for loud enviroments when commuting, usually on a bus, train or plane. 3-2 ratings means the IEM provides passive noise isolation, mainly to tune out voices or traffic, many times in-doors. Not recommended for buses, trains or planes. 1/0 ratings are rare in the IEM world but this pretty much confides it to in-doors, quiet enviroment use. 

 

[Inks]

 ​

How I Evaluate Sound Performance​

 ​

  Many will say such and such IEM is better than another, but just how and why is never clear. If one has no guidelines, no reference and rather uses a personal perception without a good knowledge of each aspect of performance (specially frequency response), they're usually preaching out of their own, personal, subjective matter. We each have our limits in what we tolerate in bass, midrange and treble levels, but it's a personal matter. As such, personal preferences are all over the place thus they cannot be used for a more objective rating system. With my approach I hope to establish the most exact method I know of establishing a hierarchy, one that is as tangible and objective as it can be. 
 

Evaluation Process​

 ​

  To complement my evaluation process, I can provide this glossary[link] that defines every term I tend to use. In additon, I have writtent this brief explanation of an IEM's frequency response [link] . I tend to describe the sound of the IEM with specific frequency regions in mind instead of using broad terms that can have different definitions. If terms are used, I provide a specific definition to keep things as exact as I can, at times the terms pretty much concide with specific frequency regions. I consider the fact that most readers are new to these technical details and thus, I provide as much information as I can and will answer questions that may get asked.  

 ​

10 point rating system​

  The best sounding producst will get a 9-10 rating, the worst a 1-2. The best sounding products are the most accurate, they maintain the purest tone, details and presentation of the recordings as it was made. Thus...
 

A flat response is Technically Better. ​

  It's as simple as that, loudspeakers with a flat response are thought to be best by proffesionals for a reason. A flat response equals to a more even distribution of each frequency brough out by a recording, this allows the IEM to be transparent to the recording, equating to a more detailed sound that mainstains the tone intended. Yes, some may prefer a boosted bass, treble or both,  it actually compromises more than a flat response because it forces recordings towards a specific tonal color that doesn't always comply. For example, a boosted bass will give the midrange a thicker presentation and warmth, but it puts a veil in details in the process, thus is may at times sound "veiled" [link]. You can't have a transparent midrange with a big bass boost as the boosted bass just won't allow it,  it brings something new to the table. Despite straying for the target, I will mention the boosts and how it may complement a specific preference, since we don't always like the highest performing sound. Of course, the higher the boosts or dips, the lower the rating of the product. To note, there can still be v-shaped, bass lenient and other such colored IEM that are fairly close to being linear flat. While mostly rare cases, it also makes the point that the aim isn't for a specific signature, the goal is to get as close to flat as possible, allowing maximum transparency. 
 

Frequency Bandwith​

  Basically how far the IEM can extend at both ends. An IEM with outstanding bandwith has good presence all the way down to 20hz in the bass and up to 20khz in the treble. 
 

Transient Speed/Imaging​

  How well the IEM keeps up with information, basically speed. An IEM with good speed has great imaging as a result. A slow IEM blends everything together and rids of the accuracy of how everything is placed. 
 

Graphs provided by Arthur Rin Choi​

  In additon to listening, the IEM's bandwidth, transient speed and overall frequency response is portrayed by graphs provided by Rin Choi. His frequency reponse graphs, I find to be the most accurate considering his well established methods. Taking out the technicalities of aside as to how and why his graphs provide an accurate picture, you can basically assume it's a simulation of how an average ear will perceive the sound. The results are basically the cold facts, your ears won't astray that far off unless it has significant damage as it's an averaged picture. These graphs play a big role in my rating system in order to maintain the most objective stance possible. 
 

Soundstage Width/Personal Listening​

  Frequency response graphs can tell me a big chunk of the peformance, but real listening is used to sum up the picture. You do have to consider my ears may have slightly different resonance aspects and my mind will inevitably be biased as are all subjective reviewers. I would mention that every IEM that has been graphed by Rin, pretty much graphs as I hear it so far. Soundstage size or width, unlike imaging, is an aspect that can't be measured and it will emphasized in my subjective comparisons. I also listen to an array of recordings, ranging from older jazz to newer rock recordings. I will mention how that relates to IEM's response as sometimes a little reservation on certain areas (especially sibilant ones) can actually be a plus as long as it doesn't astray too far from transparency. 
 

Loudless Levels and Perception changes​

  Generally, I base my listening on levels anywhere between 80dB and 100dB. I will mention how those slightly quieter levels may benefit or diminish the sound quality of the product. Very low volume levels are of little mention because a lot of fidelity is simply lost and it takes a very specialized IEM to sound good. 
 
Comparisons
You may see comparisons between products, usually of similar price range. Both graphs and subjective listening are used. 
===========================================
Sound Summary
Here, I will basically summarize the sound of the IEM as briefly as I can and how it applies to preferences, use and rating given. 

 

[Inks]

*incomplete*​

Frequency Response Graphs Explained​

 
Hertz (Hz) are am measurement of waves per second (1 KHz = 1000 Hz)
These numbers represent the highest and lowest frequencies the a speaker (or pair of headphones) is capable of producing.

 

[Inks]

*incomplete*​

Glossary of Terms​

 

 
Neutral: flat frequency response. Generally, an even distribution of all frequencies.
 
Trasparent/cy: How well the IEM allows the user to hear as much of the original nature of the recording as possible. A transparent IEM minimizes a change in tone from the way the original recording was mixed. 
 
Transient Speed: How fast the IEM is able to process information. If one compares a slow IEM to fast one in a frequency burst [I use this app], the fast one will have a faster pulse. 
 
Imaging: How well the IEM places each instrument individually, instead of blending them together. IEMs with good transient speed have good imaging, the properties coincide.

 

[Inks]

Introducing: Sleeve Line-Up for Analysis​

 ​

  In anticipation of more tip (sleeve) analysis to be done by my dear friend, Rin (udauda). I decided to compile a concise list of tips that will be used for each sleeve analysis. The purpose is to have reasoning behind tip each choice while aiding my friend in the tedious task of sleeve measurements.
 
Requirements:
 
Physical Compability: Tips have to physically fit the nozzle of the IEM. If a tip is modded to fit the nozzle, it will be mentioned. Monster nozzle adapters will be used for thinner nozzled IEMs to increase tip options. 
 
Availability: Each set of tips have to be readily available for purchase in the US (see links below). Feel free to comment on any future changes in availability. 
 
Acoustic Compability: Tips have to generally have some acoustic compability with the IEM. This means that the tip has to have some potential for good results, otherwise it will be skipped based on Rin's knowledge and experience. Generally, benefit of the dobut is given, but certain compability issues are clear. Example: While tip ER6-14 fits the first two requirements for MDR-EX1000, it is simply not acoustically compatible with this IEM as the horn-effect (due to ER6-14's much smaller output bore) will destroy EX1000's tonal balance. As shown below (fig 1), ER38-18 shows what happens when EX1000 is coupled with a sleeve that has a much smaller output diameter in relation to the output diameter of the IEM's nozzle (fig 2 below). 
 
Nozzle Thickness [Associated with Comply compability]
 
Extra Thick Nozzle [over 6mm]
Usually associated with microdrivers. Not only are these nozzles hard to insert into the simulator, there are almost no aftermarket tips that are compatible with these. Only readily available aftermarket tip options are Meelec CC51 tips. Some other aftermarket tips may fit by stretching the tip's stem. 
 
Thick
Usually Dynamics. Compatible with Comply T400

 

[Inks]

,

 

[Inks]

,

 

[Inks]

,

 

[Inks]

,

 

[gnarlsagan]

I'd like to interrupt to say that this is awesome. 

 

[tinyman392]

Quote:

 ​

How I Evaluate Sound Performance​

 ​

  Many will say such and such IEM is better than another, but just how and why is never clear. If one has no guidelines, no reference and rather uses a personal perception without a good knowledge of each aspect of performance (specially frequency response), they're usually preaching out of their own, personal, subjective matter. We each have our limits in what we tolerate in bass, midrange and treble levels, but it's a personal matter. As such, personal preferences are all over the place thus they cannot be used for a more objective rating system. With my approach I hope to establish the most exact method I know of establishing a hierarchy, one that is as tangible and objective as it can be. 
 

Evaluation Process​

 ​

  To complement my evaluation process, I can provide this glossary[link] that defines every term I tend to use. In additon, I have writtent this brief explanation of an IEM's frequency response [link] . I tend to describe the sound of the IEM with specific frequency regions in mind instead of using broad terms that can have different definitions. If terms are used, I provide a specific definition to keep things as exact as I can, at times the terms pretty much concide with specific frequency regions. I consider the fact that most readers are new to these technical details and thus, I provide as much information as I can and will answer questions that may get asked.  
 

A flat response is Technically Better. ​

  It's as simple as that, loudspeakers with a flat response are thought to be best by proffesionals for a reason. A flat response equals to a more even distribution of each frequency brough out by a recording, this allows the IEM to be transparent to the recording, equating to a more detailed sound that mainstains the tone intended. Yes, some may prefer a boosted bass, treble or both,  it actually compromises more than a flat response because it forces recordings towards a specific tonal color that doesn't always comply. For example, a boosted bass will give the midrange a thicker presentation and warmth, but it puts a veil in details in the process, thus is may at times sound "veiled" [link]. You can't have a transparent midrange with a big bass boost as the boosted bass just won't allow it,  it brings something new to the table. Despite straying for the target, I will mention the boosts and how it may complement a specific preference, since we don't always like the highest performing sound. Of course, the higher the boosts or dips, the lower the rating of the product. To note, there can still be v-shaped, bass lenient and other such colored IEM that are fairly close to being linear flat. While mostly rare cases, it also makes the point that the aim isn't for a specific signature, the goal is to get as close to flat as possible, allowing maximum transparency. 
 

Loudless Levels and Perception changes​

  Generally, I base my listening on levels anywhere between 80dB and 100dB. I will mention how those slightly quieter levels may benefit or diminish the sound quality of the product. Very low volume levels are of little mention because a lot of fidelity is simply lost and it takes a very specialized IEM to sound good. 

 
I'm answering questions in a stack-styled way   Responses are color coded
 
I think you need to read this: http://www.innerfidelity.com/content/loud-music-sucks
 
This may be true that flat loud-speakers are generally considered to be "the best".  But you have to remember when using things like IEMs, a lot of the amplification, dampering, and sound transformations that are done naturally when hitting the outer ear, ear canal, etc. are lost entirely.  "Coloring" must be done if you want a truly "flat" response.  Flatter isn't better in this case.  If an IEM was perfectly flat, it would sound mid-forward to us due to the way the ear will transform sound naturally. Even the flattest speaker can't be "perfect". 
 
Although we don't have any written guidelines, most of us stray towards the same areas when it comes to qualities.  Yes, we have extremes, and we do use them and take them into account and will mention them.  However, our quality scores are not random.  Most are merely based on how much we hear with a pair of headphones on.  Detailing, clarity, sibilance, etc are all really ways to describe the frequency spectrum. 
 
I think you seem to have forgotten why all these words were created in the glossary of terms (terms like sibilance, sparkle, sizzle, boomy, etc).  It was to become a little more objective.  Note how each word specifies a specific frequency range.  Texture being the sub-bass region, punch being mid-bass and impact in between.  Sparkle/sizzle refers to the highest of the high range while the word warmth can describe the extremely low mids.  Included with these words is the addition of a quantifying word.  Words like bad, low, ample, decent, good, great, strong, weak, etc all are used to describe the quantity that we hear something (that something being taken from the glossary).  Put them together and they give a region in the FR graph, and amount.  Yes, the quantity isn't specified, but instead, are compared to one another.  We essentially create our own "neutral" line and go from there.  Is it 100% precise?  No, but it is close enough for a person to get a grasp on what something will sound like. 
 
Outside our subjective, figurative language, there is no other way to describe sound except for hard, objective evidence.  Even the words you use above like flat, fairly flat, even presence all is subjective and not objective.  The only objective way to explain headphones is to describe a frequency graph in technicality.  "The 100-300 Hz area has a hump in it that maxes out to 5 dB above neutral" is an objective way to describe sound, saying there is firm mid-bass impact or a stronger mid-bass does not.  Even a statement that the bass has a slower decay becomes subjective. 
 
I'm going to stop before I ramble on (I think I already did).  I do think that you've missed the idea of our "subjective" words.  The truth is, everything is subjective.  Even your reviews are 100% subjective (don't worry, so are mine, |Joker|'s, ClieOS', and everyone elses').  There is no way to write in an objective manner without describing the graph directly.  But that would be boring (so please don't do this!)

 

[Inks]

Quote:

I'm answering questions in a stack-styled way

  Responses are color coded. **My responses are in Bold

I think you need to read this: http://www.innerfidelity.com/content/loud-music-sucks

Ive read that a while ago, I don't listen very loud if that was implied. I raise it just enough to enjoy all the dynamic range while avoiding fatigue.

This may be true that flat loud-speakers are generally considered to be "the best".  But you have to remember when using things like IEMs, a lot of the amplification, dampering, and sound transformations that are done naturally when hitting the outer ear, ear canal, etc. are lost entirely.  "Coloring" must be done if you want a truly "flat" response.  Flatter isn't better in this case.  If an IEM was perfectly flat, it would sound mid-forward to us due to the way the ear will transform sound naturally. Even the flattest speaker can't be "perfect". 

I do know very well that a electrically flat IEM won't be perceived as flat to ther ear. This Is why manufacturers have to use headphone-related-transfers (would call it compensation not coloration), these compensations have a general average that is base on a couple of studies. Can't link them as I'm replying with my iPhone, but the latest study in 2008 basically confirmed the ER4S as flat to the average ears. Raw measurements show a 2-9k boost on the 4S, but it's a compensation to make it flat it flat to the ear. So of course a mechanically flat isn t going to be good, it has to be flat to the ear and thats what Rin and I look at.Point remains though, what ends up as flat to the ear will be the most transparent sound. This is why I said I wanted to put the technicalities aside as it will stray my guideline into these depths. Also, I never implied perfection in either speakers or headphones, it's about getting close, there is no perfection.

Although we don't have any written guidelines, most of us stray towards the same areas when it comes to qualities.  Yes, we have extremes, and we do use them and take them into account and will mention them.  However, our quality scores are not random.  Most are merely based on how much we hear with a pair of headphones on.  Detailing, clarity, sibilance, etc are all really ways to describe the frequency spectrum. 

It's just not logical and consistent for most reviewers IMO, I think the subjective aspects just dwelve too much into it. It's not random, but filled with overlooked bias. Im minimizing It by using data and perhaps a 2nd opinion from Rin.

I think you seem to have forgotten why all these words were created in the glossary of terms (terms like sibilance, sparkle, sizzle, boomy, etc).  It was to become a little more objective.  Note how each word specifies a specific frequency range.  Texture being the sub-bass region, punch being mid-bass and impact in between.  Sparkle/sizzle refers to the highest of the high range while the word warmth can describe the extremely low mids.  Included with these words is the addition of a quantifying word.  Words like bad, low, ample, decent, good, great, strong, weak, etc all are used to describe the quantity that we hear something (that something being taQoken from the glossary).  Put them together and they give a region in the FR graph, and amount.  Yes, the quantity isn't specified, but instead, are compared to one another.  We essentially create our own "neutral" line and go from there.  Is it 100% precise?  No, but it is close enough for a person to get a grasp on what something will sound like. 

Those terms mentioned are good, there are some really bad broad ones though, like "natural" and "refined" which are far too broad. Also, a lot of the times, different definitions are used for the same words. I just try to make sure the reader and I are on the same page by having my own glossary. Your approach mirrors mine, except my flat curve is the Moller diffuse field curve, Rin's graphs help me a lot with this. The neutral line is there, do I expect an IEM to be perfect in following it? No and I may welcome slight dips from it, but again, it's about how close you get. 

Outside our subjective, figurative language, there is no other way to describe sound except for hard, objective evidence.  Even the words you use above like flat, fairly flat, even presence all is subjective and not objective.  The only objective way to explain headphones is to describe a frequency graph in technicality.  "The 100-300 Hz area has a hump in it that maxes out to 5 dB above neutral" is an objective way to describe sound, saying there is firm mid-bass impact or a stronger mid-bass does not.  Even a statement that the bass has a slower decay becomes subjective. 

Yup, whenever I describe something, it gets a lot more subjective than describing the graphs. Decay can be described in objective matters, it shows on the Spectral-Decay Data. 

I'm going to stop before I ramble on (I think I already did).  I do think that you've missed the idea of our "subjective" words.  The truth is, everything is subjective.  Even your reviews are 100% subjective (don't worry, so are mine, |Joker|'s, ClieOS', and everyone elses').  There is no way to write in an objective manner without describing the graph directly.  But that would be boring (so please don't do this!)

My issue is not so much with descriptions of sound as long as they get as exact as possible, but the evaluation for sound quality process. At least have rules and guidelines, yes without graphs, my reviews will be mostly subjective. But like you said earlier using objective evidence makes it more objective, that's a big chunk for my objective sound ratings which are based on accuracy to the source. Is it perfectly objective? No, I try to get as close as possible though. 

 

[goodvibes]

There's still interpretation of graphs and that's not an absolute. Good stuff and Rin's work is fab. I do understand the desire to have a means for an irrefutable result but I don't think it actually exists. I think when a graph has a significant aberration, then it's telling you something but minor fluctuations in steady state testing can only say so much. I think a graph can bias as easily as reveal and reading in is not beyond human nature. One way around it is to do the subjective portion without ever looking at or discussing a measurement. I think most would corroberate but I bet there would be some that don't. Not to a great degree but rankings could vary a bit.
 
Of course a graph that showed bass you didn't hear would have you re-examine the listening portion and that would be a good thing. Just an example as I know that not getting a seal wouldn't be an issue for you.
 
That said, I'm looking forward to this and Rin's graphs as I do find them fascinating and extremely well done. I really enjoy them and wish you well on this endeavor. It's as good a method as any. It's not like we can help being human, even if we try.
 
I do have a question. What kit will be used to audition? I always like when a few items are used so that any particular electrical or sonic interface is not too prevalent.

 

[tinyman392]

Quote:

There's still interpretation of graphs and that's not an absolute. Good stuff and Rin's work is fab. I do understand the desire to have a means for an irrefutable result but I don't think it actually exists. I think when a graph has a significant aberration, then it's telling you something but minor fluctuations in steady state testing can only say so much. I think a graph can bias as easily as reveal and reading in is not beyond human nature. One way around it is to do the subjective portion without ever looking at or discussing a measurement. I think most would corroberate but I bet there would be some that don't. Not to a great degree but rankings could vary a bit.
 
Of course a graph that showed bass you didn't hear would have you re-examine the listening portion and that would be a good thing. Just an example as I know that not getting a seal wouldn't be an issue for you.
 
That said, I'm looking forward to this and Rin's graphs as I do find them fascinating and extremely well done. I really enjoy them and wish you well on this endeavor. It's as good a method as any. It's not like we can help being human, even if we try.
 
I do have a question. What kit will be used to audition? I always like when a few items are used so that any particular electrical or sonic interface is not too prevalent.

 
Yes, interpretation of graphs is not a 100% accurate method, but it can give a general consensus on what the headphone will sound like.  Many properties that we talk about can be seen in the graph through comparing certain frequency ranges to areas around them as well as the frequency as a whole.  Each property would have to have a definition by objective works.  There are some things that can't be done with an FR chart though:

• Decay speed/time - This must be done with a spectral decay graph
• Detailing - Detailing cannot be shown through an FR graph 100% of the time.  Although detailing in a certain range is more likely when the range is forward, finding out if it'll detail if the range is recessed or backgrounded is still uncertain.  Many V-shape IEMs do mid-range detailing extremely well.  Take the PFE232 for example.
• Distortion - There are other graphs that can show this though
• Timbre - Timbre is such an intricate and delicacy that it can't be found on an FR graph.  It would deal with the same ideas as the rest of the properties, but since timbre isn't a specific area, rather, it's all of them and in different quantities. 
• Clarity - Clarity cannot be shown directly on an FR 100% of the time.  It is very similar to detailing...  Forward normally means good clarity, but recessed becomes a mixed bag.
• Sibilance - Like detailing/clarity, sibilance cannot be shown directly on an FR 100% of the time.  Forward highs with big troughs/peaks can mean sibilant, but doesn't have to (PFE232 is a prime example), recessed with small troughs/peaks can be sibilant at times as well. 

 
There are others as well, these are just 6 of them that are shown.  Many properties like texture can be shown if it's forward.  But if it's recessed on the FR graph, it can still have texture.  The forward areas are generally a "confirmation", but the lower areas are the ones where you may want to look into and listen for.  An FR graph can be used to confirm all subjective findings however as well as the other way around (all subjective findings can confirm an FR graph). They should be used in harmony for a really strong review.