Back when I worked for Crime Stoppers, it was my job to do presentations about preventing theft.
What I said was simple. "Lock your doors” (amazing how many people don’t). “Remove valuables from your car”. "Get someone to look after your house while on holidays”. All stuff I thought would be achievable for everyone no matter the budget.
“This costs you nothing, it’s free!” I would say, “and it's the most effective deterrent for a thief."
Yet the moment I finished my talk, people would charge towards the sales rep from one of the home security gadget manufacturers. Ready to drop $400 on a security camera which won’t stop someone robbing you. I couldn't understand it. And I think audio is exactly the same.
Ninety-nine percent of good audio has nothing to do with the sexy, shiny (expensive) stuff. Most of what makes good audio is only worth a few bucks and some elbow grease. Now don’t get me wrong. A vocal recorded on a department-store microphone WILL sound worse than one recorded on a Neumann U87. But if a decent microphone, interface, and DAW already feature in your setup, most of the gains will not come from dropping $400 (and more) on fancy new gear.
A good first step is controlling all those rogue, rascally sound waves bouncing about the room and getting into that expensive microphone of yours. Let's control that reverb!
Why control reverb and reflections?
This is oversimplifying it, but generally, a good voiceover/vocal will want a signal as dry as a physics lecture in a Dyson Airblade. No echoes.
"But Chris, my home office is OK. It has carpet".
OK then, let's try it. Go in and clap your hands once. (Warn your partner/significant/other/neighbours first, though, lest they think World War 3 has started). It should sound like you're clapping underwater, but I'll bet it doesn't. You hear all that flutter? No good. That's what's ruining your vocal intelligibility.
"But I'm never going to be recording anything that loud".
You might not. But compress that vocal and you’ll find reverb starting to rear its head as you turn the signal up. You want compressed vocals cause they sound awesome. Your room reverb does not.
"But reverbed vocals also sound awesome!"
Yeah, we've all heard The Naked and Famous. But their reverb comes from a plugin modeled on an acoustically perfect reverb chamber that an engineer can turn up or down to ensure that vocals sound perfect, before anything gets committed to the record. Can you do that with your room reverb?
So what do we do? We think about controlling some of those sound waves so they enter the microphone once and once only. Sound getting in after bouncing off the walls three or four times makes the “smeared” reverb effect and ruins a good recording.
Do I need a reflection filter?
If you work in a properly treated room, absolutely not. You're better off treating the room rather than trying to attach the treatment to the microphone.
You might accomplish this by recording in a room with a lot of soft surfaces (i.e. your walk-in wardrobe). Use your ears and see what works. My walk-in closet sounds crap, despite the absorption of my puffy vests, flannelette shirts and humorous t-shirts. Instead, we usually achieve this by attaching lots of absorptive material to the wall.
Where a reflection filter shines is if you record where room deadening isn’t practical (like a home office). Or if your landlord has thoughts about you attaching huge foam panels to the walls. Or you want something more professional-looking than recording between two couch cushions. In that case, attaching the deadening to the microphone becomes better than nothing.
Now they are by no means a silver bullet- remember the massive hole in the front of the shield still lets in reflections! But if you have your mic placed in front of a wall, a computer monitor, or your collection of commemorative Franklin Mint plates, it will help to tidy up reflections. Especially those entering your microphone through the pickup lobe at the back. (Yes, even cardioid microphones still pick up sound from the rear).
Should I buy a reflection filter?
You can, but I prefer not to drop more than $400 on half a foam cylinder. (insert Darryl Kerrigan quote here). They probably are better than a homemade one, but there comes a point where the return on investment is better spent elsewhere.
Aussie radio host and podcaster Rachel Corbett has a fantastic if more… er, “ghetto” solution. But a cardboard box (whilst probably effective) doesn’t have the professional vibe I'm looking for. I’ve also seen these things made out of cut-down buckets and plastic tubs. But I’m a woodworker (albeit a terrible one). So let’s break out the saws and get cutting!
Making a reflection filter:
Our piece de resistance is this: a convoluted foam mattress topper. The foamy goodness will help soak up our soundwaves, while the convoluted shape will help scatter reflections that do bounce off. This makes them less likely to bounce directly into the microphone, and helps dissipate their energy. This was $35 from Target Country (RIP) but I’ve heard they’re around for a lot cheaper.
If you’re a hoarder like me (much to Kate’s dismay) then the rest of the list of materials will be “stuff lying around the house”. But if this next bit requires you going to the big green box for a sausage in bread (other hardware stores are available), then I would buy:
Put it together!
Welp, the proof of the pudding is in the eating, as nobody says (because they always just say "the proof is in the pudding", for some reason...). But does this thing actually work? Take a listen to how it sounds before and after:
As you can hear, there's definitely less reflection in the last recording. The test would be even more stark with a nice sensitive condenser microphone (it's in the post... watch this space!) but even with the dynamic podcast-grade mic you can hear the difference.
A couple of things that will make the thing work even better:
So what do you think? Let me know if you do end up building your own, and what you might improve. I hope I've inspired you to make one of your own, and maybe think about taking even more of a DIY approach to your audio production!
Made one? Tweet me a picture @Chris_Plumridge
Chris Plumridge is a freelance audio producer, voiceover artist and writer from Leongatha in South Gippsland, Victoria, Australia.