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Why a completely flat response is what we all want in listening audio equipment

cedd

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#1
I'd like to point out this is a philosophical matter and not something that can be answered with science or numbers.

My reasoning is simple. We use listening audio equipment to listen to the waves encoded by recordings, not the waves encoded in our listening audio equipment. If the latter were the case there would be people listening to headphones without a recording playing; obviously no one does this... lol...

The Harman curve is imprecise. It is not ever going to be the same for everyone as everyone's ears are different. This means, by using it as a metric, we end up in the situation we're in now with a vast array of audio equipment that are all targeting slightly different curves, resulting in an infinite numbers of colorings and no fixed authority to say one more faithfully reproduces a recording than another. The end result is the diminishment of influence that any recording has over the listener's experience. At best, adherence to the Harman curve distorts the recorder's intentions, making their recordings more pleasing to hear by picking up the slack in their poor choices. At worst it stifles recording practice growth and maturity by hiding to the recorder their unadulterated choices, failing to give the honest feedback necessary to improve.

The Harman curve is extremely useful in sound engineering, particularly when making a pleasing song or soundscape. I don't deny this. But that is not an excuse to force it on every recording regardless of if the recording's intention is to sound pleasing or "balanced" to our ears or not. And certainly if someone just wants to listen to pleasing sounds they would probably benefit by tuning their listening equipment to this curve. But that doesn't make it a valid metric to judge the equipment's frequency response against.

A flat response is flat for everyone. It's the only sensible aim for listening audio equipment and it's what all equipment should be striving for.
 

lashto

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#3
Before writing a page long rant it's a good idea to check your facts.
The Harman curve for HPs is not "flat response". It does not pretend to be. It was never intended to be. It is just a preference curve. As in " most people seem to prefer it so"

Admittedly, ASR could/should do more to clarify that, yours is a very common missinterpretation.
 
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cedd

cedd

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Thread Starter #4
I think you may be misunderstanding the Harman curve. It's the in-room result of normal, furnishings etc, NOT what the equipment provides. The equipment is flat anechoically or electronically, the Harman curve is the desirable result in-room.
S
Okay, let's assume that adhering to the Harman curve is just creating the perceived "room" of the headphones. Let's imagine what this means for a recording engineer/artist making a recording. They now have to guess whether their expected listeners are using listening equipment tuned to the Harman curve or a flat response. If they're using monitors with a Harman curve (which again isn't precise and may differ from their expected listeners) then they can just mix their recording more or less transparently. If they're using monitors with no curve applied (a flat response, which is mathematically definable) and expect Harman-curve-tuned listeners then they now have to mix with an inverse Harman curve filter applied to get an idea what their listeners may hear.

I just feel like a goal that's mathematically defined will produce more consistency than one not so defined. I agree most people, myself included, prefer a Harman curve applied to most recordings but I think as a rule that should be the responsibility of the recording engineer/artist to adhere to if they want their recording to have that specific room applied or not.

And thank you for the welcome ;)
 

abdo123

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#6
uhmm... this is kinda all over the place.

The harman curve is not 'forcing' anything on you. it's a representation of what a neutral dispersion of sound is in a room.

if your in room response follows the harman curve, that means that sound decays in a way that is consistent and that is perceived as neutral in our ears.

headphones don't have a downward slope because you don't have reflections and as a result you don't care about sound decay. you're just adjusting to the effect ear lopes have on sound with increased treble.
 
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cedd

cedd

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Thread Starter #7
a line sloping downward is mathematically defined
What would be the practical reason for a downward slope response over a flat response? A flat response has the unique quality of being as faithful as possible to the input.
 

abdo123

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#8
What would be the practical reason for a downward slope response over a flat response? A flat response has the unique quality of being as faithful as possible to the input.
because what leaves the speaker is not what enters your ear.

it's like you want to make a pizza at home, and instead of getting the actual ingredients and making it you just eat everything raw and uncooked.

Edit: changed analogy.
 

q3cpma

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#9
What would be the practical reason for a downward slope response over a flat response? A flat response has the unique quality of being as faithful as possible to the input.
Others may not have been clear enough: the Harman or older B&K curves just describe what response a flat speaker will give in a typical domestic room, due to the greater absorption in the medium and high frequencies. Mathematically, flat anechoically <=> downward slopping in most rooms, so said curve becomes a target unless you live in an anechoic room.

By the way, you might wonder "why not EQ the speaker to be flat at the listening point?". Because you don't hear the PIR like it is shown, as if your hearing were omnidirectional, the direct sound will sound too bright.
 
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devopsprodude

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#11
What would be the practical reason for a downward slope response over a flat response? A flat response has the unique quality of being as faithful as possible to the input.
There is no reason. The comment was meant to note that just because something is mathematically defined does not make it useful, or even good.
 

sergeauckland

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#13
What would be the practical reason for a downward slope response over a flat response? A flat response has the unique quality of being as faithful as possible to the input.
Home furnishings absorb high frequencies more than low frequencies, so a loudspeaker with a flat anechoic response driven by flat electronics will end up having a downward tilted in-room response at the listening seat.
Equalising for this downward tilt by boosting the higher frequencies that get absorbed more results in a subjectively bright sound, as the room no longer sounds 'normal'. That's what the Harman curve describes, the desirable natural sound of a 'normal' room which has a downwards tilted response.

S
 

Racheski

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#14
What would be the practical reason for a downward slope response over a flat response? A flat response has the unique quality of being as faithful as possible to the input.
Found this post from Amir on r/headphones
Harman tests are preference tests. They play various pieces of music and in double blind testing determine what response was preferred by the listener. Their work on loudspeakers has proven over and over to be correct and even followed by their competitors. On headphones it is newer and not yet as established but the research is quite sound. I have participated in their loudspeaker testing and there, my preferences perfectly matched their overall results and that of their expert listeners.

So I would say yes, you want to try to use their target curve but don't be shy about deviating from it. Ultimately a target curve is a default starting position that is preferred by many. You likely fit that profile but there is no crime in changing things up and down.

Note that there is no attempt to create a "flat" response. Such a response is not preferred in either speakers or headphones. Rather, the curve represents what we think is "uncolored." For headphones for example, we crave more bass since we don't have the tactile feedback of speakers, or the bass loading of the room.
 
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cedd

cedd

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Thread Starter #15
Others may not have been clear enough: the Harman or older B&K curves just describe what response a flat speaker will give in a typical domestic room, due to the greater absorption in the medium and high frequencies. Mathematically, flat anechoically <=> downward slopping in most rooms, so said curve becomes a target unless you live in an anechoic room.
I see now. It's compensation for the fact there's no room to color the sound in a headphone. That's an interesting dilemma actually. On the one hand I understand why it's being done but on the other it seems like headphones open up a unique soundstage unto themselves that speakers in a room can't replicate.

Thinking about it, the most logical solution seems it would be applying EQ profiles in software or hardware to achieve whatever room simulation you prefer and leaving the headphones with a flat response for clarity and evaluation's sake. Hardwiring a preferred room makes sense for the average consumer but it seems an unnecessarily claustrophobic and heavy-handed solution for audiophiles like ourselves, or am I missing something?
 
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richard12511

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#16
I'd like to point out this is a philosophical matter and not something that can be answered with science or numbers.

My reasoning is simple. We use listening audio equipment to listen to the waves encoded by recordings, not the waves encoded in our listening audio equipment. If the latter were the case there would be people listening to headphones without a recording playing; obviously no one does this... lol...

The Harman curve is imprecise. It is not ever going to be the same for everyone as everyone's ears are different. This means, by using it as a metric, we end up in the situation we're in now with a vast array of audio equipment that are all targeting slightly different curves, resulting in an infinite numbers of colorings and no fixed authority to say one more faithfully reproduces a recording than another. The end result is the diminishment of influence that any recording has over the listener's experience. At best, adherence to the Harman curve distorts the recorder's intentions, making their recordings more pleasing to hear by picking up the slack in their poor choices. At worst it stifles recording practice growth and maturity by hiding to the recorder their unadulterated choices, failing to give the honest feedback necessary to improve.

The Harman curve is extremely useful in sound engineering, particularly when making a pleasing song or soundscape. I don't deny this. But that is not an excuse to force it on every recording regardless of if the recording's intention is to sound pleasing or "balanced" to our ears or not. And certainly if someone just wants to listen to pleasing sounds they would probably benefit by tuning their listening equipment to this curve. But that doesn't make it a valid metric to judge the equipment's frequency response against.

A flat response is flat for everyone. It's the only sensible aim for listening audio equipment and it's what all equipment should be striving for.
The Harman "curve" is a completely flat response. It's also a preference curve, but their DBTs discovered that the flattest response is also the most preferred.

Or are you talking about the Harman headphone curve? That one is also based on a "flat response" after accounting for HRTF, but it also has a boosted bass response that is boosted above flat. I think the headphone curve is more controversial.

BTW, I agree with your reasoning for wanting a flat response.
 

John Dyson

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#17
The problem is that almost all consumer recordings have been processed by a multi-band compressor. The best that you can do is to go to a boutique shop where the mastering engineer has full control. The commercial distributors try to protect their IP. You don't think that they distribute their family jewels, do you? They want to give something limited quality that passes as tolerable. This is all about the original 'digital sound' that started in the 1980s, but like smells, vision, taste, etc -- the lister has become accomodated.

If you want really good sound -- you gotta go boutique, or find a way to undo the compression. (BTW, the compression doesn't sound like traditional compression -- they played some tricks to hide the damage below -20dB.)
 
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cedd
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Thread Starter #18
The Harman "curve" is a completely flat response. It's also a preference curve, but their DBTs discovered that the flattest response is also the most preferred.

Or are you talking about the Harman headphone curve? That one is also based on a "flat response" after accounting for HRTF, but it also has a boosted bass response that is boosted above flat. I think the headphone curve is more controversial.
From what I understand the Harman curve and the HRTF are two separate but related things. The reason we like the Harman curve is likely due to the HRTF balance installed in our inner ear. I can see the argument that a flat response (reproducing exactly what's in the recording) in a headphone sounds unnatural as the headphones have what we perceive as an unpreferable room color (for whatever reason, maybe familiarity or again the HRTF?) and therefore a Harman curve can be nice to apply here.

I still don't think it justifies hardwiring it into listening equipment for anyone but the average consumer. If you're an audiophile then you're likely interested in EQing to your own particular HRTF, and wouldn't mind the added cost and sophistication to do that. A problem arises when there's no agreed upon standard for listening equipment to strive for. So we now have some manufacturers striving for a Harman curve and others for a flat response. My argument is that what's a better judge of a piece of listening equipment's quality than how accurately it reproduces the raw input signal? If one or multiple points in the signal path are applying their own interpretation of the Harman curve then it just becomes madness for the listener to manage and compare. Who are recording engineers supposed to mix for? The equipment hardwired with a flat response or the equipment with its own special Harman curve? There will never be consistency with the latter option, and we'll always end up where we are today in a market with endless reinventions with insignificant tweaks congealing into an unmoorable muck by the inability to judge them from a common standard.
 
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#19
Apart from the Harman Curve being a preference setting of audible pleasure that finds favour among listeners, it is also timely to remember that it is a useful commercial tool for manufacturing product that will appeal and be more readily sold to consumers.

Given the results as I understand them it was a much favoured by audiophile listeners as it was by the great unwashed, untrained average consumer.

In the global competitive world of audio in all of its forms, any significant audio product manufacturer that aims it product at the audiophile only audience (apart from specialist boutique companies) needs its head read if they are going to make profits, compete rigorously and try to increase market advantage and size.

The Harmen Curve is a pretty good weapon in achieving that aim.
 
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