Interesting post about SPL i saw on Reddit

[elecktrickboogaloo]

so i saw this argument going on, about whether SPL affects listening. Chris Lord Algae said listening at lower levels helps with mixing decision. In my experience it clearly does, but a poster replied with some interesting statements that make me question:


A: "I remember seeing this before. Watched it again now because I was fairly sure there was some misinformation in it but couldn’t remember what. For all music production purposes, SPL has no bearing on room acoustics. Monitoring quietly will not improve your acoustics as the direct and reflected sound scale linearly."

B: It won't improve the acoustics, as the acoustics are unchanged. But it's a known phenomenon that monitoring at lower levels will bring up the room less. Try it in a church and you'll quickly realize that there will be a big difference between monitoring loud and monitoring quiet.

A: The ratio will be the same regardless. You have less room but you also have less direct sound. The tail of the reverb will be quieter and fall below the noise floor quicker so it may appear as if there is ‘less room’ but that’s only really noticeable if you play short bursts of sound or stop playback. The reverberant field will be constantly re-excited with continuous playback. Critical distance theory, determining the ratio of direct to reverberant sound, is d(c)=0.141√QSα, there is no variable for sound pressure.
I’m not an acoustician but that’s what they say is the case, no matter what psycho acoustic effects we think we perceive. The only way to change that ratio is to move closer, increase monitor directivity or increase the absorption coefficient of the space.

now, this all sounds very interesting, but i seriously smell false information disguised as pedantic faslehoods, but i am not an expert...


here is a link to original if interested
https://www.reddit.com/r/mixingmastering/comments/16dgkpw/_/jzrof80

 

[alex-z]

The loudness has absolutely nothing to do with room acoustics, regardless of the source volume you will have the same reflections, and therefore decay rate and ratio of direct vs reflected energy.

When mixing quietly you are in a less sensitive part of the ear/brain equal-loudness contour. This causes the mixer to add increased bass and treble, which matches listener/consumer preference at low volumes. This can be problematic if the listener is using high volumes, bass will become boomy, and treble will sound shrill.

What really matters is the mixer knowing how their actions translate to the final product. This is part of the big push for neutral studio monitors, giving professionals a known reference rather than needing to overlook flaws in their equipment.

 

[elecktrickboogaloo]

The loudness has absolutely nothing to do with room acoustics, regardless of the source volume you will have the same reflections, and therefore decay rate and ratio of direct vs reflected energy.

When mixing quietly you are in a less sensitive part of the ear/brain equal-loudness contour. This causes the mixer to add increased bass and treble, which matches listener/consumer preference at low volumes. This can be problematic if the listener is using high volumes, bass will become boomy, and treble will sound shrill.

What really matters is the mixer knowing how their actions translate to the final product. This is part of the big push for neutral studio monitors, giving professionals a known reference rather than needing to overlook flaws in their equipment.

Right, I don't think either of them are saying that loudness affects room acoustics.. but one is arguing SPL affects perception of room (Chris Lord Alge also says this) and it seems like the other is saying that listening doesn't affect perception of sound (says what Chris Lord Alge says is misinformation), and they use the critical distance theory as evidence.. but to my knowledge, critical distance theory is for designing rooms and spatial purposes, but NOT for perception of sound. (It seems your statement agrees with this). If anything wouldn't the Critical distance theory need to incorporate the fletcher munson curve somehow to even begin to address perceived sound?

I am just trying to weed out truths from nontruths in what they are saying

 

[ozzy9832001]

Mixing at lower volumes would only allow your perception of the low and high end to change. I would think mixing at lower volumes would actually cause a boomy bass and overly bright high end.

However, due to the same Fletcher-Munson curve, I would say that loudness does effect the perception of the room, but only in a system that is not equalized.

 

[Blumlein 88]

Read up on the K system mixing levels from Mr. Katz. Based upon Dolby research into proper loudness levels for playback. That research btw indicates lower levels for smaller rooms and louder for larger spaces.

 

[sam_adams]

Lower monitoring levels make sense if your studio has a good NC rating. NC 15 - 20 is recommended for studios and it's very hard to get below that for commercial spaces without tremendous additional expense.

Some info from Bob Katz on K system metering as mentioned by @Blumlein 88:

Bob Katz Level Practices part 1.

Bob Katz Level Practices part 2.