You can see from various articles in 2011 that I was totally NUTS about diffusion (see the Recording Studio Construction and Acoustics category) I built a crap load of diffusors that year . I was hoping they would be the holy grail. I became OBSESSED with ‘em. I was researching them obsessively. I was doing QRD math equations every night. I couldn’t sleep I was so excited about diffusion. I had to know of PRD vs QRD. I had to know about 1D vs 2D. I have to know how important depth was. I was mad because I had to go on a vacation when I could be building my diffusors. Diffusion! Diffusion! Diffusion! Surely, it was going to be THAT THING I was missing.
In one of my articles where I was PUMPED UP about diffusion Danny Danzi made the following comment:
Brandon, I’m gonna go against the grain here a bit. You and everyone else will probably disagree with me. However, having worked in some pretty incredible rooms in my life recording drums, “the kit” as well as the tuning, mics used AND the player is what made the difference way more than any room I’ve recorded in. Though a room and having control over that room is important, in my experience rooms have not made a huge difference for me as much as the other stuff I’ve mentioned.
This quote is of intense value because anyone can list those things that are important, but it’s decidedly different when priority is put on those things. Just for the sake of clarity, Danny isn’t saying that he’d prefer to work in a terrible room. He’s simply stated that a great drummer with a well-setup kit can overcome much.
I have to agree with Danny…now. My room was not my biggest problem and no subtle tweaking (like that of diffusion) was going to move any mountains.
Diffusion is a good thing at the right time. It takes a gang of 10 thugs and splits them up into single law abiding sound waves, give or take. It’s an interesting alternative to putting them in jail, which is what absorption does. The net result is bad reflections ain’t bad anymore, but it takes a huge diffusor to bust up the low end (see George Massenburg’s Room). It’s easy to pretty up the reflections in the 1k-4k or so (depending on depth and diffusor design) and still have a mess in the low end. There’s differing views as to how far away you have to be from a diffusor for them to work well and even more debate over the quantity of sq ft needed to be “adequate”.
So what does that mean in terms of recording quality?
Diffusion CAN do a lot if the room is good but boring. This is a big deal in live rooms. In the too-small home recording situation, “boring” ain’t the problem. Downright crappy is the problem. Diffusion isn’t exactly the right tool for solving “crappy”.
After a room experiment I took my 2D diffusors down. They are stacked up in storage right now. I never bothered to put ‘em back up. The effects weren’t that interesting to me in my current circumstances.
What I did find was going MegaDead (Now that’s a band name! Way heavier than Megadeth!) with room acoustics is almost always a good thing in home recording land. I have strong evidence coming in an upcoming Hyper Guide. The fear of a “too dead” room makes no sense in a room too small to have any good reflections anyway.
In the typical single-room confines of home recording land, it’s best to go neutral in the room that’ll be used for mixing. No significant obvious reverb (the kind of thing that makes you sing in the shower). That’ll cover you for everything but the bass significant instruments. We still have the problem of room modes that wreck low end response of studio monitors affecting our bass cabs, but that’s not a mega issue for tracking for non-low end instruments like vocals.
Lesson Learned: I should have just been proactive and used more EQ and overall processing. Some voices need it.
What I found was I got more aggressive with my EQ after I had diffusion. Why? Because I found out that they didn’t automatically solve my problems….any of them. That 150-300Hz crappy stuff wasn’t the room and I was running out of things to attribute it to. It turned out most of my problems were simply the resonance in the vocal cords of the singers I was dealing with and guitars I was wrestling with. Not all singers and acoustic guitars had it and that was the real clue. (This lesson of more proactive signal processing is an ongoing theme.)
The good room reverb is great if you’ve got it, but I doubt many of us have it. Go dead and move on until you have the luxury (large room) to choose otherwise.
In short: Diffusion is cool, but it’s not a holy grail for everyone all the time. In the home recording world where we need to be sucking up every ounce of low end we can from bouncing around our rooms, it doesn’t make sense to waste an opportunity to suck up some more low end by tossing diffusors up instead. (Ethan Winer’s Realtraps offer a diffusor with a bass trap built in. I like that!)
Ultimately, I would have been just as content with a bunch of 4″ thick Roxul sheets 12″ off the wall. Of course, I went bigger than that.I replaced my wall of diffusors with a wall of 16″ thick bagged Roxul.
I don’t miss the diffusion.