How should real flatness sound like?

Submitted by gotok1324 t3_zxg98y in headphones

When I try to flatten a set of headphones or speakers, I always end up with a muffled sound if compared to the Harman curve (which is how flat is supposed to sound, given that the curve represents good speakers in an acoustically treated room).

My method to do so is to have a sine wave playing for around 1 second in every note of the piano roll and try to achieve the same amount of gain/energy for the whole frequency spectrum. This is more of an experiment, but I've done it a couple of times and I always seem to get the same results.

Is this how real flatness should sound? Because I literally did this to fit my own ears/hearing. So I can assume that's flat for me (?)

How could it sound so different from something like Sonarworks (which they claim to be real flat) or the Harman target curve? (Maybe, because it's too far off, my method is wrong? I mean, Sonarworks and the Harman target curve aren't so far off from each other, but my results are way far off from these two.)

Does this sine wave method even make sense?

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----_________------ t1_j2050f0 wrote

do not use sine sweeps for flatness. as u/The_D0lph1n said, the brain perceives different frequencies as louder or not. Sine sweeps might be useful for dips/peaks and channel matching, but thats pretty much it. Use music (or pink noise) and adjust using a reference if you want flatness

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TheFrator t1_j207057 wrote

If OP wants to know more- here's a decent wikipedia article on Equal-loudness contour - https://en.wikipedia.org/wiki/Equal-loudness_contour

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gotok1324 OP t1_j20cpjn wrote

I just read the page. Very interesting subject, specially about the changes the Fletcher Munson curve had and ended up being actually close to what we have today as the standard. Thank you!

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WikiSummarizerBot t1_j2071ue wrote

Equal-loudness contour

>An equal-loudness contour is a measure of sound pressure level, over the frequency spectrum, for which a listener perceives a constant loudness when presented with pure steady tones. The unit of measurement for loudness levels is the phon and is arrived at by reference to equal-loudness contours. By definition, two sine waves of differing frequencies are said to have equal-loudness level measured in phons if they are perceived as equally loud by the average young person without significant hearing impairment.

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gotok1324 OP t1_j206shw wrote

Thank you! Some time ago I tried to match my little USB speakers to the sound of my headphones calibrated to the Harman target, and I managed to get a pretty decent sound, even from these cheap speakers! I'll try to do it using pink noise though, sounds interesting

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The_D0lph1n t1_j202vh3 wrote

Oh, you're not supposed to try to get perceived flatness on a sine sweep. The brain expects certain frequency ranges to be louder, so if you get a flat sine sweep response, you're naturally going to have a really muffled and dead sound. Don't do that.

The sine sweep method can be helpful for identifying sudden peaks, but it should not be overused to try to make it sound flat the entire way.

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gotok1324 OP t1_j205eb3 wrote

Oh! Never really linked the points hahah The frequencies I tend to turn down when doing this are really the ones in the 2k-4k range, which is where we have the Harman peak... Thank you!!

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mcjasonb t1_j20wapo wrote

Flattest is probably somewhere close to the Etymotic ER4SR. Most people will say that they have no bass though. They measure flat in the bass with a rise where the lack of ear gain would be.

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YQ_Polymathica t1_j23leog wrote

Yeah, Etymotics are quite good at hitting the neutral target, although one should take the different HRTFs of people into account. For some, they're the epitome of neutral; for others, less so.

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mcjasonb t1_j23wskv wrote

How much is there to really take in to account when they go in as deep as they do? They obviously bypass the outer ear, how much of the inner ear is left to change the sound person to person?

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Expensive_Yam_1742 t1_j2129yr wrote

Headphones shouldn’t be flat on an FR graph like speakers because of the different way they interact with your ears. That’s why there isn’t a Harman curve for speakers. So if they sound like crap truly flat, that’s why. That being said, how do you know if it sounds flat? I’d say you’d have to have a trained ear and try to use songs with real unamplified acoustic instruments. If they sound natural, then it is probably close to flat. Not a huge fan of the sine wave technique because it isn’t real music so if you care about the music aspect rather than technical aspect I’d go with what I suggested above.

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DWW256 t1_j22v3aj wrote

The Harman target isn't actually flat. If you go back and read the research, Olive et al started with their own "good speakers in a good room" and then took input from a group of trained listeners on tweaking the bass and treble response.

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YQ_Polymathica t1_j23koku wrote

To be a bit more accurate: he asked a few hundred listeners, some trained, some untrained, to select their preferred sound, and he tweaked the curve accordingly. So the Harman curve isn't a neutral curve, it's a preference curve. Not flat.

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gotok1324 OP t1_j244ber wrote

Is there any variant to the Harman target that's meant to be completely flat?

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mcjasonb t1_j2afjdm wrote

Harman is a bit V-shaped. Some will say it’s well balanced, but it’s definitely a bit V-shaped. I’m not saying that’s a bad thing though.

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sustained_vibrations t1_j20hfj8 wrote

Boring and soulless tbh

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RodRevenge t1_j20k7n0 wrote

How does soulless sound?

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sustained_vibrations t1_j215n7h wrote

Robotic recessed mids, linear non rounded bass, and treble that makes it feel like icicles are getting gouged into your ears.

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YQ_Polymathica t1_j23l4jm wrote

Maybe just my purist preferences playing around here, but I don't think that flat necessarily sounds soulless like that, although definitely a bit boring. For me, flat means tight bass in quite meagre doses, unexciting but natural mids, and a somewhat cold but not harsh treble.

To be fair, I don't like DF either, because I don't think DF is neutral for mastered tracks, maybe for recorded tracks at most. For mastered stuff, something like IEF neutral is closer to flat for me.

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