How Do We Perceive Loudness?

We discuss how humans perceive loudness as it related to noise, music and tones. It's often cited that it takes +10dB to double loudness. Where does that come from and is it true? We explore all of these topics and more in this livestream broadcast.

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#loudness #sound #music

[rb]

The length of time a certain sound is present also determines how that sound is perceived by the human brain. A "longer sound" is often perceived as a "louder sound".
That is why it is good to use "pink noise" as the sound source when measuring "loudness" in a given environment. Music as a sound source is often too random to be used as a reference "sound".
Pink noise is a good way to measure frequency response in a listening space, but it does not take into account the "modes" in that given space.
In my personal experience, using pink noise AND sine-wave sweeps has been the more accurate way to measure a room.

[dvan]

I always give you a thumbs up you have great video's👍👍👍👍👍👍

[aaronarchy]

Nice overview of a really complex topic. People always talk about how amazing the human eye is, yet the the ear is equally as complex. The ear is so sensitive, the difference in sound pressure between the loudest and softest sounds we can perceive is a factor of x1, 000, 000, 000, 000. (120db-SPL). Also, you should absolutely do a video on safe sound levels and risk for hearing damage. This is a vastly overlooked topic among the audio community, and you are correct that the 85dB OSHA standard is just not sufficient. Also, the 85dB standard follows an A-weighting curve, which doesn't make sense when considering the loudness contours. I've routinely measured spikes of >120dB-C at my local theater. Most theaters, especially ones like IMAX, set their levels way too high for comfort. The "bigger is better" mantra is just silly, and dangerous. People don't realize the risk of hearing damage from these systems.

[jimshaw]

A good attempt at explaining these issues. And due to the variability of people, I think it's as close as we're gonna get. Our hearing is largely logarithmic, and most people cannot, will not, or don't care about any mathematics that isn't linear. So, it makes it difficult to explain hearing judgment.

As always, I learn from and enjoy Matt's enlightened efforts to explain the meta territory between the science, the mathematics, and the average listener. And I really appreciate the targeted research he does in preparation for these talks. I hope Matt will keep going.

[stevorcompton]

As always super informative and was something I was thinking about in the last week as far as why we are using 1k output to base the efficiency of a speaker and what are the outputs at different frequencies. Glad I’m not the only one that thinks about these things and I certainly appreciate listening to you two discuss the subject intelligently. Happy Tday and my best to you and yours! Thanks for all you do to educate against fraud!

[aegisofhonor]

the loudest I ever pushed speakers in my home was to a point where my receiver was hitting about 75 watts. According to the specs of my then Pioneer CS-N771s (since then I replaced them with TZ-7), they had a sensitivity of 88db at 1 watt. Going by that figure, I have determined the loudest I have ever listened to with speakers in my home was 106db and I will say, that sounded VERY loud to me, almost hurting my ears it was so loud. So if 75 watts of power and 106db of sound pressure is enough to bring me to the very edge of "too loud", then I'm wondering how anyone can listen to music any louder then that.

[carlosarniz]

Really informative, this scientific approach is truly welcomed.

[SwirlingDragonMist]

If speaker manufacturers are going to keep pushing the breakup points of their tweeters outside human hearing, it would be nice if they would consider the equal loudness curves that our pets may have in their hearing. This area of concern is also probably why dogs loose it when there are seemingly not even very loud fireworks going off. “Petmode” is the loudness button of the future! I had an old Yamaha with a loudness ~knob~ on it, I thought it was a pretty cool party trick. If ya ask me, the more knobs the better.

[flyzipper]

Future video suggestion... house curves.

I apply one on my MiniDSP 2x4HD for frequencies less than 100hz, and enjoy the result (that's the main thing, right?), but I've gotta imagine sound engineers are aware of these loudness concepts and factor it into their mix, so users applying their own house curve might not be the most "accurate" representation of the content.

[mobilemcsmarty]

great topic, loved the vid guys, thanks! ok, so now I know about phons and sones. what I want to know next is how is this relevant in our gear? our ears will apply the same perception curves to a live performance (let's say non-amplified/acoustic) as to the reproduction through our audio systems. I appreciate how the perception curves change at different volumes so let's say we set the audio system to the same volume as the performance. can I make the conclusion that the perception curves cancel out and we'll want our systems to just be flat?

[kirkcunningham]

In my hometheater which is currently a 5.2, i listen to movies around 80db with LFE bass peaks at around 90-95db depending on the movie. Plenty loud enough for me. Im 8 feet away from the mains and center. Subs are 10 feet. My room starts to roll off bass at around 28hz.

[jonwatchesnyc]

Thanks for all the great content! Question - why is loudness subjective, if SPL is an objective measurement? Why isn’t loudness defined as a relationship between two spls? Thanks!

[davidouellette]

GENE CAN YOU TELL ME WHY DENNON DISCONTINUED AVR X-4300H I OWN ONE AND LOVE IT JUST RECENTLY GOT A GREAT DEAL ON KLIPSCH BUNDLE WITH BEAUTIFUL TOWERS AND PUT A MARANTZ MM7025 2 CHANNEL POWER AMP TO OPEN UP MY TOWERS SOUNDS AMAZING ALSO GOT A COOLER FOR THE TOP OF MY DENNON BECAUSE I NOTICED THAT IT GO SO HOT IN MY CABINET. THAT FIX THE PROBLEM NOW I CAN EXPAND MY SPEAKERS IF I GET A GOOD DEAL. SEEMS TO ME THAT THEY STOP MAKING THE X4300H AND REPLACED IT WITH THE X4500H CAN YOU EXPLAIN WHY DID HE HAVE PROBLEMS WITH IT OR WERE THEY GIVING TO MUCH FOR THE MONEY .LOOKING FOR A BLUE RAY PLAYER NOW BUILD AS I GO WANTED THE OPPO 205 BUT THE PRICE IS WAY OUT THEIR NOW ALSO ANY SUGGESTION IN THAT DEPARTMENT. KEEP UP THE GOOD WORK VALUE YOUR OPINION THANK YOU

[UpgradingAsUsual]

For me, -40 from Reference with a Denon x3300W (in a small room home theater) is loud enough. I'm sure in a larger room I'd be on -30 or -25. Usually I notice people put their theaters louder to get more bass because of inadequate subwoofers. As long as your subwoofers are adequate or overkill and the bass is as loud and clear as you prefer, the rest of the speakers can stay level matched to the subs. Maybe for another subject or video.

[geoman]

Do you have Video how to match speakers & external amplifier? Coz my 3 front speakers is 200 watts max each & my 4 rear speakers 100 watts max each. Is it ok to to connect 7 speakers with 200 watts balance outlaw 7220 or 130 watts outlaw unbalance amp? is my 4 100 watts speakers will blow up? what is the ideal a greater watts amplifier than speakers watts?

[i]

I like that even young folks say next "slide", even though they have never seen a slide projector. :-)

[Quetzalcoatl]

There aren't many movies that have 115db of bass for more than 30 seconds at a time.
Explosions take no more than a second of audio. Then your ears have time to recover. So 115db is just fine.
The bomb explosion of Ready player one is probably the longest rumble i've heard and i don't think that's more than 30hz.

[finitevoid]

this is fab -- more like this please :-) not everyone has a sub or multiple subs -- some listen on 2x channel. would love to see a video defining crossover (physical hardware *not* software) types pros and cons :-)

[RBzee]

The last two 'fake' IMAX theaters I went to were way too loud! I had to put my earbuds in to tolerate it.

[isaacsykes]

Thanks for the video guys! This raises so many questions, like decibels in relation to distance, mating amplifiers to speakers to achieve said DBs at said distance; to how efficient should my speakers be? I'd also like to suggest a topic: can you guys please address "Gain" in amplifiers: what to look for; why that is such a hard spec to find; and why manufacturers choose to highlight or promote watts over "gain". Thanks and keep up the great work!