Is a FLAT response the IDEAL?

Sounds in nature are not a flat response, quite often, there are natural attenuators, accelerators and amplifiers, including horns (caves), wind and water, let alone reflections, absorption and diffraction.

Similarly the holy grail (one of them) of recreating outdoor, concert or live music, and so on, abound with these shifts in the environment or context where the experience happens and the recording takes place. Are we depending on the mic positioning, and mic performance, along with mixing equipment, format and so on, to enable recreation of the environment when moving to playback. How does a flat response curve help?

Of course, we have DSP. For Club, Hall, Rock, Indoor, Outdoor and may other shifts to music recordings. And mastering adds reverb as another way to create a 3D version of context/venue. These are averaging processes that apply universal shifts to shape a standard curve across the music stream continuously.

So why is it that we pursue flat response curves? Or DSP generated fixed curves? How does flat recreate that live ’being there’ experience.

When designing equipment including components, such as DACs, and speakers, most seek to judge against a flat frequency response.

Mind you, how on earth can we allow other than flat. Turntables as most here know, use the RIAA curve to fix the problems of hearing that itself is not flat. But even that is aimed to deliver a flat hearing response.

I don’t understand. If we are trying to model or capture the original event, how does flattening everything help? And, what are the alternatives? How do we achieve close to the venue or location, given so many unique variables, that our approximations just don’t seem close to the original. It’s no wonder... Have we selected flat because it is the best average we’ve got?

Do immersive audio methods of sound reproduction do it better? Some prefer pure stereo, some like DSP, some multi-channel and multi-speaker methods including ambiophonics.

Where does the ’flat curve’ fit into the equation here, vs say cross-over design or powered speakers or upgrades as a priority? Should we care about it?

Well that’s enough to launch this inquiry...


I guess I'll go first. ;-)

As just one example of your misunderstanding: the RIAA curve is not used "to fix the problems of hearing that itself is not flat." I could explain what the RIAA curve is and why it is used, but a simple Google search will give you the answer. I'll let others address matters of their own choosing.

The word "flat" relates to how well your system REPRODUCES whatever has been input to it. In other words, how far your system deviates from the original

NOT that the sounds / music / etc will be flat!


For any normal acoustic performance, the direct sound you are hearing is a flat response. The non direct sound will not be. It is the same with audio.

The direct sound from the speaker to you, the listener should be flat. The total response including the room will be preferred if it declines in volume as the frequency increase.

Speaker position, toe-in, listener location, and room acoustics, and room correction are your variables to achieve both a flat direct response and a listener taste room response.

Listener position frequency response should be smooth with most people preferring rolled off upper frequencies.  The amount of roll off and at what frequency point varies by individual.  At the same time you cannot ignore time domain issues.

Flat means that the system reproduces what the musician recorded exactly.  That is my goal.  not everyone's goal.  for example, rap and hip hop systems generally greatly exaggerate the bass.


Flat means that the system reproduces what the musician recorded exactly. 

Flat on axis does usually, flat room response usually does not.

I don't know if a flat response is the ideal sound for me or not. I just know all the albums I have I grade D, C, B, A, and A+ based on how good they sound to me. A flat response is one of the least important criteria I listen for.

Unfortunately, the word "flat" carries an unattractive connotation. The word implies dullness and lack of life. What it means in the hifi game, though, is truthfulness. It means that whatever music you put into the system, it’ll reach your ears with the qualities the creators intended to convey.

There is no ideal response. What you need is custom tuning. Every track you play requires its own curve. But nobody has yet invented a system which can store a different EQ preset for every track. The ideal curve is not fixed because it will depend on the room, your ears, speaker placement, recording and your preference. On some days you might want a little more highs, on other days you might want less. 

Flat is just used as a marketing tool by the speaker companies to sell their speakers. A flat response looks impressive. A ragged curve does not. 

The studio pro folks love flat tuning. They dont care about sound quality they just want flat so thats what the speaker companies give 'em. 

Hifi folks are generally more fussy so you have a variety of curves being offered on the hifi market. Some are flat as a pancake but some are not. 

If you want to change your response, you need an EQ. You can then have whatever curve you like. 

I love how even a topic that has only one possible answer still becomes a debate. Darn audiophiles!  This one was a gimme!

There are many factors involved in reproducing a recorded signal. Some are more important than others which is why when some factors are not done well the sound may still be better than when other factors are done well. But the goal is for every factor to be accurate. Flat response should always be a goal although I consider it a secondary factor. I find dynamic linearity, minimal compression of level changes of all magnitudes from micro to macro a primary factor in sounding real. But anyone not attempting to achieve flat response to be in error.

@kenjit ,


If you want to change your response, you need an EQ. You can then have whatever curve you like. 

No you can't. An EQ will change both the direct sound and the room response. Fix one and you can break the other. EQ is not a substitute for a good speaker and the matching room.

Flat is a reference point.  But, it really depends on personal preference, in the end.

No you can't. An EQ will change both the direct sound and the room response. Fix one and you can break the other.

The OP is not talking about room response. He just wants to know if flat is right or wrong. I have answered that. 

An EQ has already been used even before you plug in your speakers. The mastering engineer and the mixing engineers would have used plenty of EQ unbeknown to the audiophile. The EQ would have been used to balance the sound but you will need to retune the sound because everybody has diffferent hearing, different room and different speakers.This is why every speaker on the market has a different frequency response curve. Every speaker designer has their own opinion about what sounds good and so every speaker is tuned according to their preference and their room. The goal of an audiophile is to go out and find a speaker which is miraculously tuned exactly to your requirements and that of the speaker designer, which is highly unlikely wouldn't you say?

AFAIC the only way you could truly get true reproduced flatness in record playback is if your listening room and playback equipment are identical to that which recorded it. other than that it is a crapshoot. the most you can hope for in the real world is to avoid the noted audio sins of shriek and boom and to have sound clean enough and close enough to relative neutrality that you can discern something of what the original recording engineer heard in his studio control room. you are NOT gonna hear but an approximation of what went on in the studio auditorium itself, not even with krell and wilson on hand. it is, with the exception of minimally mic’ed direct to stereo recordings in real spaces, all a game of manufacturing and consuming sonic sausages.


(1) Aspiring to make the the room response flat is desirable because it helps to remove the particular way that a particular room alters the sound of recorded media upon playback—it’s a room-specific endeavor, not a global ideal, and the point is not “it sounds good.” The point is accuracy. If the recording is bad no equalization will make it sound “good;” EQ to your heart’s delight to make it sound “good” to you;.

(2) OP obviously didn’t read the Wikipedia article from which he or she copied the graph; if he or she did, it would clearly be understood that the RIAA curve is a solution for the challenges presented by the vinyl record medium to accurately reproduce the recorded sound—it has nothing to do with room response; it is not a good or bad, like or dislike, subjective, choice, judgement, kind-of-thing. It’s more akin to zipping a computer file and unzipping it when needed—nothing sexy or controversial about that.


Nice unsupported accusations about me there.

Here’s some quotes from Wiki

“The purposes of the equalization are to permit greater recording times (by decreasing the mean width of each groove), to improve sound quality, and to reduce the groove damage that would otherwise arise during playback.”


”RIAA equalization is a form of pre-emphasis on recording and de-emphasis on playback. A recording is made with the low frequenciesreduced and the high frequencies boosted, and on playback, the opposite occurs. The net result is a flat frequency response, but with attenuation of high-frequency noise such as hiss and clicks that arise from the recording medium. Reducing the low frequencies also limits the excursions the cutter needs to make when cutting a groove. Groove width is thus reduced, allowing more grooves to fit into a given surface area, permitting longer recording times. This also reduces physical stresses on the stylus, which might otherwise cause distortion or groove damage during playback.”

I suggest this is a much wider discussion than what has been raised so far. Your point could have been served by sharing this: 


I like flat, try to achieve it when possible.  Currently....*shrug*....tolerable, a whack space, basically.

Preferred with beverage, no.  Spouse isn't. *L*

@kenjit Truth, to beauty. 👍

@emrofsemanon , ditto...but take a breath, or at least, Caps. ;) *whew*L*

and even if you were so fortunate as to get truly accurate playback that was within a whisper of the control room's playback, you might not even like it that much. we all hear differently, lord knows i've heard mixes that made me scratch my head in wonderment at "what in tarnation was that blinkin' engineer thinking, was this recorded by a daggone committee?

It’s supposed to be…..I still like to use my ears, remember we’re “audio” philes.



Sigh ......

This is wrong. Ideally you are trying to match to what was done at the time of mixing and mastering. It is almost guaranteed that was done near field, one of the reasons why a flat direct sound is important, more so moving forward as studio monitors are fast becoming all active with very close to flat responses.

A room response declining in frequency matches more closely what a venue may do to the overall sound. Think about how music is recorded. Microphones close to the artists, absent the impact of where they are recorded. Not exclusively, but most. When someone is working on the mix and master, they are playing with left/right levels, and maybe frequency balance to place the artist in the recording, and then they are adjusting the overall tone so that it sounds right.



(1) Aspiring to make the the room response flat is desirable because it helps to remove the particular way that a particular room alters the sound of recorded media upon playback—it’s a room-specific endeavor, not a global ideal, and the point is not “it sounds good.” The point is accuracy. If the recording is bad no equalization will make it sound “good;” EQ to your heart’s delight to make it sound “good” to you;.

@kenjit, The OP is not talking about room response. He just wants to know if flat is right or wrong. I have answered that. 


You provided an answer that is both correct recognizing differences in rooms, speakers, people, while ignoring or not understanding there are two critical aspects of frequency response, direct, and room. If you use EQ, you will adjust both at the same time. You may fix the room response, which may provide you good tonality, while breaking the direct response which is necessary for good imaging, and for the correct sound of attacks.

Personally, and this is just me, I want to hear music that is as close to what the musicians played as is reasonably possible.  That means as close to flat as I can get from my equipment.  There are external factors that I have varying degrees of control over, but at least I know my equipment is not a (significant) part of the problem.  So for me, yes, flat is ideal.

Turntables as most here know, use the RIAA curve to fix the problems of hearing that itself is not flat.

Hahahahahahah.  That's not even close to accurate.

Here’s the typical Kenjit post pattern:

1. Post non-issues

2. Ignore thoughtful, fact based replies

3. Offer no solution

 No, you have to have some life in your room! Think of a symphony hall. Think of how it sounds. It’s far from flat.

HI JOHNREAD57!  What you like is what's ideal for you. Don't let anyone else make decisions for you. No two people hear the same thing. Our ears are of different shape. The sound you like is the best sound for you. Happy Listening.

Thanks everyone for sharing your perspectives. Love the humour, good cheer and facts shared.

For me “Flat Response”, as a single parameter, tells nothing about a music systems ability to:

  • Portray the feelings, that the musicians try to tell
  • Involve me in a emotional way
  • Not boring me
  • Keep me interested in listening

As is - unfortunately - I’ve heard way too many systems, that just bored the life out of me?!?…

Peter Comeau, the entertaining English golden ear speaker designer for IAG (Wharfedale, Mission, etc) has done some good interviews on this subject. He suggests that his approach to being the final filter for his companies was liberated when he finally realized the flat performance was not his goal. He rejected over 170 trial and error crossover designs for the modern Mission 770 speakers before settling one. It’s good to be Peter I assume :)

OP has a fundamental misconception of what is meant by a flat response.  Early posters above tried to point out and correct this but to little avail and now everyone's gone off at tangents.  I'll try again.

A musical event is recorded.  The frequencies in the event are not flat - i.e. all the same sound intensity, or volume.  The objective in recording the event and replaying it on replay systems is to reproduce the event as it happened, i.e. with the loud bits loud and the soft bits soft.  The systems that are employed to do this should have a flat response, i.e. every frequency is recorded and replayed at the sound intensity/volume it had in the event.  That requires a recording and replay system that is 'flat', i.e. it treats every frequency input the same and does not make it louder or less loud that it was in the event.

Summing up.  The system is flat if it records and replays all frequencies as they occurred in the event, not louder or softer.  A flat system does not make the sound intensity of all elements of the event the same (as OP seems to apprehend, incorrectly).

Let me see, where did my flat response misunderstanding start... I'm a logical thinker, other than when I'm not, and can be both at times.

Flat response to me does not speak at all to it's meaning in use here in the audio world. 'Flat response' suggests an outcome that is flat. Clearly not the intention. I get that.

Let me repeat my problem. Flat response suggests an outcome that is flat. Just plain simple English. Maybe neutral not flat, or unchanged and not flat either. Neutral or unchanged far better convey the intention not to add anything or take anything away be it frequency, amplitude, place, timing and so on. Flat? No. Flat means flat. Flat what? At each and every moment in time, being measured, by a mic or ears or whatever, there is no additional (or loss of) information, change or disturbance, perturbation or otherwise in (tempted to say the force...) but will say the music/audio signal(s) being heard or recorded. Flat? No. Doesn't make any sense yet. To me.

Just accept it mate. Ok, throw away logic. Not yet.

Flat is a state not a transformation. In mathematics which I studied (among other things) a flat transformation (as a term or as a function) doesn't exist as far as I know. Other than its equivalent here - a zero transformation. Yet, here, the term flat transformation means no transformation (like in the maths sense), no changes are made to the original audio signals. You see I am trying to talk my way into understanding this term.

But the mind wants to think, flat means to flatten. And that drift, that urge is driving my misunderstanding. Response is an action (a verb), a flat response in this case is a zero action. This is an oxymoron. Ahhhh. And I think it's the juxtaposition of these two terms that is triggering my mind to think flatten - otherwise it doesn't make sense, logic. Zero response (I like zero transformation even better), easier to comprehend in this case, than flat response. Flat is a shape descriptive, flat surface, flat tyre, flat land, what do you imagine a flat response looks like? Visually? Duh?

Flat response means no response. Since when does flat mean none? Flat means flat. Flat response, is an oxymoron. You mean zero response, and here we go again, unchanged.  

Now I understand why I don't like the inadequacy of this phrase. Its an oxymoron. Unless someone can show me otherwise. Its an acculturation rather than a matter of logic, that has combined poor word choices into a phrase.

If a person gives a flat response, what would she/he be saying or doing? Nothing? This phrase doesn't make any sense. Just as it doesn't with mic's, equipment or anything else for that matter. No response, zero response, no transformation, no change (more simply), these are all easily understood alternatives, that don't risk sliding into oxymorons. 

Are you giving me a flat response here? You speak in oxymorons? ;-)


No,no,no.  You guys got it all wrong.  Regardless of any non-linearity of your hearing or from the environment, you want you playback hardware to have a flat frequency response.

I'll chime in here as well.  

I'm sure others have touched on this.

First off, Flat Response refers to how the piece of equipment (amp, pre-amp, etc.) is designed to reproduce signals.

in other words, if the amp is designed to amplify signals from 20 hz to 20 Khz for example, then you definitely want that amp to have a absolutely flat response between 20 hz and 20 khz.  a 20 hz signal should have a particular gain/response level from that amp.  a 1 khz signal should have the exact gain/response level from that amp.  A 20 khz signal should have the same gain/response level from that amp.

That is a flat response.  The amp, pre-amp, etc. isn't adding of subtracting (missing) any information to the signal.  it is not adding a signature of it's own.

However, many designers design to add additional bass or high frequency response to their equipment.  This most definitely not a flat response.

I want my equipment to reproduce the signal exactly as it came in, flat from 20 hz (or lower) to 20 khz (or higher).  Anything else is cheating and is adding a certain "sound" which is not accurate in the slightest.

Now, if the amp is designed in conjunction with a particular speaker for example, then there may be a need for some wave shaping circuitry to correct for the speaker's issues.  many speakers require this wave shaping correction.  However, it is typically in the crossover and not in the amp.  my point is certain equipment is designed together to correct for issues from other equipment from the same manufacturer.  This why as a system they sound great, but when used separately with other equipment, not so much.

thanks, enjoy