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Acoustic Treatment Before And After Comparison

Discussion in 'Backline' started by AntonioPetrole, Jan 16, 2018.

  1. AntonioPetrole

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    Hey all,
    So I just moved into my new house and in doing so, I decided to put together a comparison between before and after acoustic treatment in my home studio. I've included the raw files from my field recorder in the video description so you can play around with it and do some analysis. I'd love to hear what you guys think of the difference and I'm more than happy to answer any questions you may have.

    I highly recommend you download the raw recordings in the description of the video for a better understanding of the difference. Youtube can do some funky things to audio files and you might not hear certain things while watching.



    Bass Traps and Early Reflections


    My room dimensions are 11.5' x 11.5' with a 7.5' ceiling. I decided to treat my left and right side early reflection points with 4" absorbers that are 32" wide and go from floor to ceiling. To treat the 2 corners behind my speakers, I made 2 large bass traps (not superchunk, just regular panels) that are 6" deep and 47 inches wide, floor to ceiling. For the rear corners, I used regular 4" panels parallel to the wall since my door blocks the ability to have a panel that straddles the corner.

    All of the traps use Roxul Safe 'N Sound. I was able to salvage it from my old traps that I made. Honestly the biggest and longest part of building these was the finish. Cutting, sanding, staining, and finishing the outside wood frame took waaaay longer than just building the 2x4 frame and stuffing it with rigid fiberglass. I will say all in all though I love the way they look. Another downside is the money you need to spend to do those cosmetic parts of the project.

    Quadratic Diffusers

    At my last house, I didn't really do much to treat the walls behind me. That room was about 14' long from the side my speakers were on to the other side. I did a lot of research on how how diffusion works and how to calculate the most optimal build, and so I set forth and decided to build some quadratic diffusers.

    Let me tell you, this was a tremendous pain in the ass to build and cost me a lot more money than I care to admit. Every cut I made had to be exact, and I only used a circular saw for the entire studio build. It was a lot of tedious cuts, a lot of double measuring, and a lot of those white monster energy drinks to propel me through each sleepless night.

    I used QRDude to do all of the calculations that I needed. I decided to go with an 11 well design because I figured it gave me the most bang for the buck while also not being impossibly detailed to build. One thing that's awesome about it is that it gives you the minimum distance from your sitting position to the back wall as part of your calculation.

    Now, the deeper that you build them, the lower frequencies it can diffuse. In my case, I decided to go with a 7.25" depth for my room. which treats down to about 765hz. Technically that 765hz is true diffusion, but I hear people talk about how there are still some things going on to about an octave below that. I could have technically gone deeper since my sitting position is a bit farther than that, but I tried to do as much as I could to balance between the ideal measurements and whatever I could do to buy lumber that meet those requirements as far as dimensions to save me from more cuts.

    I typically see that diffusers are built maybe only a few feet tall and are hung from ceilings or wall mounted. My understanding is that this is mostly due to manufacturing costs, shipping limitations, and cost. I built mine floor to ceiling because I didn't want to have to damage any of the walls at my new house trying to mount a heavy diffuser. So I ended up building 3 and putting them all side by side. Any more than that, and you start running into issues with periodicity. You can read more about that here https://books.google.com/books?id=IDAuR3dn5ZsC&pg=PA248&dq=the+curse+of+periodicity&ei=zCTFSqSGGqeKlQSOo7zDAw&hl=en#v=onepage&q=the curse of periodicity&f=false

    I included my QRDude final calculations as well below
    https://imgur.com/a/Ifqhq

    If you're not super good with power tools and working with wood, I'd stay far away from building these types of diffusers unless you're really willing to put in the immense amount of time that they take. You're probably better off just treating them with more absorbers, but in my case I wanted to do something different. One big thing I've noticed since I put them in is my room sounds larger than it actually is. It's hard to describe and I don't think that translates super well in the audio clips I provided.

    Final Thoughts

    After doing these audio comparisons, I came to a few conclusions about the treatment I ended up doing.
    1. You would think by adding bass absorbers, that the bass would get quieter since it's being absorbed. However what I found is that the bass is much more prominent now and well defined. I presume this is because there was cancellation in the lower frequencies which left it inaudible. I noticed big nulls around 70hz and 140hz
    2. After doing my tests, the treated room sounds much more like the original audio than the untreated room. The untreated room lacks any definition below 150hz and the reflections were real bad. It made it sound like a really bad sounding quick reverb was on the tracks.
    3. In the comparisons, it's clear to me that the stereo image has been cleaned up and there's more information that's much wider.
    4. There was a certain mid range honk before the treatment was done, this seemed to disappear after the fact.
    5. I still think there is a null at about 100hz based on my comparisons. But everything already sounds much better, so I can't complain too much :)
     
    #1 AntonioPetrole, Jan 16, 2018
    Last edited: Jan 16, 2018
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  2. Redline4

    Redline4 Member

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    That was an awesome video !! After treating my room as well (superchunk floor to ceiling bass traps in all corners plus six 6'' thick wall panels, a 6'' cloud and 2 QRD diffusers on the back wall) I can confirm what you experienced ; no more ugly ''quick'' reverb and the bass is much more stable, defined, controlled and present.
     
  3. Star Ark

    Star Ark Member

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    Do you guys think it is possible to get significant bass frequency improvement for under $1000? Not just a small improvement but a decent and reliable low end? I'm using a fairly simple starter acoustic panel pack and it helps in a lot of ways for spatial info: I get all my delays and reverbs and panning much easier, I track acoustic guitar and voice with a more direct sound etc but virtually no help with the eq decisions as far as I can tell.
    I know it's a big question with a lot of variables but I have some audio money to spend and it's either going on some slate products or room treatment
     
  4. newamerikangospel

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    There are way better mixers/engineers than I here, but in my opinion/experience, If you get rid of things that you cant work around, in my experience mostly stereo smearing, the rest is learning your rooms curve and nulls. Having your speakers and listening position in the right spots will be 80% of the fight. Play a set of songs you know, and tweak.
     
  5. AntonioPetrole

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    What's your starter acoustic panel pack? Is it like one of those foam packs from guitar center? What is the size of your room? What monitors are you using? I can provide a bit more info if you can provide that

    Honestly you can buy a ton of Roxul Safe 'n Sound or Owens Corning 703 (more expensive but more rigid), buy the cheapest fabric you can, and build thin wood frames (they'd support the fiberglass easily) and treat your whole room (corners, early reflection points, back walls, corners at the top corners of your room, cloud) easily for under $1000. You'd probably have about $250 - $300 after that depending on the deals you can find. Keep in mind it might be a way cheaper and easier idea to just get good open back headphones to reference the low end. I personally hate mixing through headphones but it's definitely an option.

    One thing I will say is that being good at mixing (knowing the tools, trained ear etc) will get you way further than acoustic treatment will. I've just recently started taking the URM audio courses (Joey Sturgis, Eyal Levi, Joel Wanasek) and I can't believe how far off I've been my whole lift after applying just a few of the simple practices I've learned on it. But it doesn't hurt you at all to have a treated room.
     
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  6. Star Ark

    Star Ark Member

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    ^ I got 12 of these
    Frequency Range: 200Hz and above

    Dimensions: 600 x 600 x 75mm

    And 4 bass traps which I cannot find the dimensions of.

    I'm in Australia and I bought them off a guy who designs the acoustics of universities and other things like that. I sold musical equipment and we did shop renovations and he was the biggest name in acoustics so we hired him. His panels are much thicker than regular ones and he claims they go as low as 200Hz, but my low end is still boomy and of course it could be a lot of things. I even managed to get this guy over to my old house and he implied I needed to spend thousands however he had just given us quotes on the shop renovations so I doubt he would agree I could be cheap at home and then hand us a huge bill for the retail outlet. Basically some people are so full on I get the impression it is not worth doing unless I go all out? But then other people seem to think less extreme

    I use event 20/20s in a rectangular room slightly too small for the monitors. They are 6 inches in a 7 inch box and I plug the sound holes with rubber to tighten the low end and have rubber for decoupling. Honestly your suggestion of using high end headphones may be a better solution, I completely forgot about that option.
    Cheers
     

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