Should you use Fletcher-Munson loudness compensation?

[AncientMariner]

Our brain is a powerful EQ on its own and has expectations how combinations of sounds should sound like.

I thought of an example to illustrate that I don't mean that in a mumbo jumbo way:

Imagine you listen to a girl singing who is standing in front of you. You now move 20 meters away from her, and the volume of her voice is reduced. According to the research done by Fletcher-Munson, the lower frequencies of her voice will have dropped off by some dB to your ears.

But your brain will compensate and her voice will sound the same to you just at a lower level. You're not going to think "wow, her voice sounds really thin now". You brain EQ'ed the missing dB.

Now you listen instead to a girl singing through your speakers. You listen at 80dB and it's like she is standing in front of you. Now you reduced the volume by 20dB. If you use Fletcher-Munson curves to compensate for the lower volume, you boost the lower frequencies of her voice, and all of a sudden her voice sounds muddy and dark. Because you brain will not accept this is the tonality of her voice at this volume level/virtual distance.

This is why I don't think it's correct to compensate using Fletcher-Munson curves.

We can, however, boost the overtones/treble to add clarity, and the sound below 200Hz to add some of the tactility that was lost due to the lower volume because it won't impact the tonality of vocals and instruments that much.


I think the objective with loudness should be to obtain a pleasing sound, which may include tricking our brain. The accurate representation is to play back the music at the same level it was recorded.

 

[ZolaIII]

That's what works for me, yes. But it's subjective. What I would advice is to simply adjust it to your liking. If you're "critically listening" (not a fan of that term), i.e. concentrating on the music and want an accurate representation, you're likely to listen at a louder level anyway.

You can try to make a filter like described by solderdude on page 2:

Should you use Fletcher-Munson loudness compensation?

I know many are familiar with the Fletcher-Munson or equal loudness curves. In a nutshell: “The Fletcher Munson Curve contains a set of graphs that show that when you listen to music at a lower volume, mid-range frequencies will be sound more prominent, whereas high and low frequencies will be...

audiosciencereview.com

E.g. with the values in the pic attached and try to listen to it at lower volume.

It sounds really really bad. It's muddy, dark, and lacks treble. There is no clarity. Vocals are mumbled.

Compare that with the filter in the second screenshot. Sound is clear and airy. Vocals are crystal clear as they would be if listening a much louder level.

My own personal conclusion is that equal loudness contours only tell how a person perceives the level of one frequency vs another in isolation (which is how the tests were conducted). It's not really valid to how we perceive complex sounds such as music. Our brain is a powerful EQ on its own and has expectations how combinations of sounds should sound like.

Edited: As a sentence accidentally slipped out.

It's second screenshot regarding Q (Butterworth) but it's meant to be a lot higher at 105 Hz. What can make or brake things is how attended are transition frequency above the 105 Hz and I advise crossover at 120 Hz for sub's (which then nead to be to the mains and in 2.2 one each chenel configuration). You don't need to do it subjectively, you can use SPL meter and form there adjust to the curve output on speakers by JRiver (ISO 226 2003) screenshot. Rest is more to the subjective taste do you like slight boost (about 2 dB) in sub bass and can do it technically or not. The highs filter is less important and pronounced and comes into play only under 60 dB (normal speech loudness) programme SPL.

 

[Old_School_Brad]

Yes, you should use it

The equal loudness curve *is * psychoacoustics. Why would you think we somehow 'compensate' for it? It is a measurement of how we actually hear. You not only hear disproportionately less bass , you also perceive it so.

It is why loudness buttons were invented.

+1

And Yamahas approach is very nice. If someone (Dirac?) comes up with an active solution like a fixed microphone and a loudness function on- the fly related to SPL I'd buy it.