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Atmosphere and Tone Quality

Discussion in 'Live Sound [BG]' started by Bubble, Feb 2, 2018.

  1. Bubble


    Apr 17, 2013
    I'm beginning to notice what's in the air affects tone quality. I am staying in a small apartment, well sealed. If I forget to let fresh air in, it gets stale with out-breathed CO2.

    And I noticed my amps were sounding sort of muddy in the midrange sort of like what I call the "speaker in a coffee can tone". I opened the windows and renewed the room air and got immediate improvement.

    To make a consistent tone quality, keep the room or hall air fresh.

    Here is a reinforcement to my theory :

  2. thekyle55


    Mar 14, 2012
    Maybe, but you have neither of those gasses in your room. It's psychoacoustics or something else affecting the tone.
  3. Pat Harris

    Pat Harris Supporting Member

    Nov 17, 2006
    Austin, TX
    I notice more of a discernible difference in humid vs. dry conditions.
  4. Bubble


    Apr 17, 2013
    Average 20% humidity. I do have some nearby speakers that need to be turned but no, it has to be atmosphere. Those two gasses do what they do because of their density. They are being used to show two points in conjugate.
    There are other effects between and probably beyond those and standard atmosphere for base calculations.
    As a quick look, CO2 could very well affect midrange perception.

    Taken from Wikipedia :
    At standard temperature and pressure, the density of carbon dioxide is around 1.98 kg/m3, about 1.67 times that of air.

    Carbon dioxide - Wikipedia

    Speed of sound in air, 1125 FPS, in CO2, 913 FPS, CO2 is -212 FPS, obviously open to delay, phase and other wave distortions.
  5. Bubble


    Apr 17, 2013
    I have so many other problems I'm working on, but as a quick look, if the air in the room is able to settle and separate by height, then parts of the wave will also be out of phase and by height of the speaker box, travel out with different perceptible differences, and darn, what do we have ? An atmospheric phase shifter like with the pedals.

    Toss in the very detectable difference in altitude density. I can measure easily in one foot increments. It also shows churning effects.
  6. tlc1976


    Aug 2, 2016
    Then I better make sure my bed isn't at the same level as the CO2, or CO if any exists in the place.

    Could be humidity. When wood or other materials are very dry, they can be more resonant.

    I also wonder about vacuum in the place. You said it's well sealed. If you (or anyone in the same building) is running exhausting appliances and the place doesn't have the required amount of make-up air, you can draw a vacuum in the place. Might possibly make your cabs sound different if they're sealed.
  7. Bubble


    Apr 17, 2013
    As soon as I can, I will set a bookshelf speaker down in a box and (yuk) breath down into it and see if it affects the sound. This is down in a semi-basement apartment.

    I had been wondering how all the alcohol vapors, CO2, and other human emissions in a crowded gig might affect the sounds. In addition to the known damping factor.
  8. Bubble


    Apr 17, 2013
    At a gig you can add a correction factor. My original descriptive was "The Six Beer Stereo". It was so terrible it took six beers to not notice how bad it sounds. The want a beer or one beer stereo sounds pretty good. More than 6 beers and just about anything sounds ok. LOL
    BadExample and jon mccumber like this.
  9. okcrum

    okcrum in your chest

    Oct 5, 2009
    Verde Valley, AZ
    RIP Dark Horse strings
    Lobster11 likes this.
  10. SteveCS


    Nov 19, 2014
    Hampshire, UK
    It won't affect 'the sound' one bit but if there is that much alcohol vapour in the air you might better question the ability of the brains of those producing the vapour to process what their ears are telling them...
    shoot-r, Downunderwonder and DirtDog like this.
  11. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    As a sound provider in the Pacific Northwest. I get to do tent shows... temp and humidity are evil things we deal with everytime. Festival setting on a typical spotty rain day. When it’s sunny, people are out looking at exhibits, etc. soon as it sprinkles they pour into the tent and the mids change dramatically as the temp and humidity increase. Sun comes out, they all pour out and the mids go nuts again... usually it is mids cranked with people on the tent and then slammed down as they leave...

    I have a super loud rock and roll band in a tent on St Patty’s day... no doubt it will be *fun*.
    SoCal80s likes this.
  12. Lobster11

    Lobster11 Supporting Member Supporting Member

    Apr 22, 2006
    Williamsburg, VA
    Sorry, I don't buy it. But I'd love to have some of whatever it is you're smoking down there....
  13. SoCal80s


    Oct 1, 2015
    The change in temperature and humidity is more likely what you’re hearing.
  14. Spyrosaab

    Spyrosaab Swimming in the deep end.

    Aug 27, 2011
    Melbourne, Australia
    I find that my stereo sounds better in the winter in that the bass is stronger and clearer overall. Being colder thus denser the air probably couples to the speakers better. Also I recall a radio show many years back where they played traditional singing from I think it was Mongolia - you could hear all these overtones normally swamped by warm air. The temp was somewhere south of -20*C. My home stays much warmer than that lol.
  15. Bubble


    Apr 17, 2013
    Density changes or gradients can cause diffraction and diffusion. It makes a sonic lens that could make the waves bend and beat themselves. Believe it or not, in a closed room, not stirring, the sound will travel faster near the ceiling than near the floor.
  16. derrico1

    derrico1 Supporting Member

    Apr 12, 2005
    Charlottesville, VA
    Sure, theoretically, small changes in gas composition will make small changes in acoustic behavior. But I suspect a much simpler explanation accounts for the majority of any perceptible change here.

    Namely, relative to a small space, the bigger the doors or windows (especially if they're massy and well sealed), the more opening them will change the acoustics of the space—not only in terms of reflections but also standing waves.
    Lobster11 likes this.
  17. tlc1976


    Aug 2, 2016
    Things are usually so much quieter in the winter. No frogs, cicadas, or much of any birds or animals that make noise. The snow absorbs a lot of sounds that normally accumulate, and of course covers up rustling leaves, snapping sticks, etc. All the overtones would be much clearer. But on the flip side, you're either bundled up for the cold, or shivering and preoccupied with the cold.
    Spyrosaab likes this.
  18. Bubble


    Apr 17, 2013
    I opened the windows to purge the old air then closed them. It is usually 75°F and 20% humidity. Last night a front went through, windy, and most likely a new baro pressure. Today it sounded excellent.
    So, baro change or purging the air from some small leakage of 30+ mph wind ? I'm going to track baro pressure and how it sounds.
  19. Coolhandjjl

    Coolhandjjl Supporting Member

    Oct 13, 2010
    What’s the best atmospheric gas for metal?
    Last edited: Feb 6, 2018
    agedhorse and arbiterusa like this.
  20. Bubble


    Apr 17, 2013
    For full spectrum music, water vapor in normal atmosphere, 90°F and more than 50% humid. Water vapor displaces denser air and allows better transmission. High frequencies are absorbed by air, why you hear rumble-rolling thunder in the far distance and not the sharp clap. Sound travels better in the fog because water vapor is less dense than air.

    Dry air attenuates higher frequencies, maybe why the mids seem to punch through, it's actually the highs being absorbed and accent the mids as if lowering upper sliders on graphic EQ's.

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