acoustic treatment

We’ve been doing a series of posts over the last 5 weeks – giving you tips on how to improve the quality of the audio you record in your home studio. The first of the series is here: Improve The Quality Of The Audio You Record At Home – Tip 1.
The first 4 tips were all about technique – ways to immediately improve your audio without having to buy or build anything. A huge majority of people recording in home studios using converted bedrooms and don’t use any acoustic treatment in their rooms. I’ve recorded this way for over 10 years. The problem with doing it this way is that the rooms in our houses have notoriously bad acoustics – making your audio sound reverb-y and echo-y.
So the first 4 tips in this series showed you how to reduce that bad room sound in your recordings immediately, without having to buy or build anything. Then last week, week 5, we talked about microphones – how no matter what mic you currently use, you can almost certainly improve your audio by upgrading to a different mic without having to spend a lot of money – in fact most can do this for $100 or less.

The Best For Last

In this week’s tip I will share something that has completely changed my life (yeah, sounds dramatic but it’s true). II put acoustic foam on my walls that just about totally eliminates that bad, echo-y room sound!
NOTE: This final tip – though it is super helpful in a home studio – is not strictly necessary to get professional sounding audio. I recorded everything for my voice-over and music careers in this same studio with only tips 1-through-5 for several years. But if you CAN afford to do it, make it happen ASAP.
There are several types of acoustic foam that you can use to treat your room with. Auralex is probably the most popular manufacturer, and they have several packages to choose from. I went with a less popular (but a bit more expensive) brand called “Acoustic Fields.”
Regardless of the brand you choose, You’ll want to cover up a pretty fair percentage of the walls in your recording room. Look at the picture at the top of the page to get an idea of how much foam I have on my walls. I put foam starting at about my waist level and going up to the top of the wall.
Overall, I’d say about 20 to 25 percent of the walls have foam on them. You can probably get by with less than that if you place them on the wall opposite where you face when you record, and also on the wall behind your normal recording position.
I recommend starting with about one pack of 14 of the Auralex 1-foot square panels. then if you need more, you can add panels until those echoes are tamed.
Once some of this foam is on your walls, it absorbs the bad room reflections without sucking the life out of the sound of your voice, as is the case so often with other room treatments.

Our Tests With The Foam

Before putting any foam up on the walls in my converted bedroom studio, we wanted to do some before and after tests to make sure it would truly make a difference. So my wife (Lisa, fellow voice-over artist and singer) and I did a series of male and female vocal recordings – spoken, shouted and sung – with no foam on the walls.
Anyway – the tests. After recording samples with no acoustic treatment on the walls, we basically covered the walls with foam, leaving no more than a couple of inches between panels. Then we recorded the same samples. We – were – blown away! There wasn’t even a hint of room sound after the foam went up.
Next, we removed every other panel to find out how much treatment was enough. It is possible to overdo it. Well, it sounded great with no hint of room sound at all. Removing every other panel opened up the sound slightly as well —- “letting the audio breathe a little” is probably the best way to put it.
Below is a bit of the before and after audio. The samples were recorded 18 inches from the microphone to maximize the effects. The shouted phrases were also chosen to send a quick loud vocal through the room. This song for the singing sample was chosen for the same reason, AND the fact that it’s in the public domain. Also, the before and after samples have been normalized to be the same volume to eliminate loudness as a factor. Though the difference is clear listening on your speakers, to hear how truly dramatic the difference is, try listening with headphones;).
Before

Male “Before”

Female “Before”
After – WITH The Foam On The Walls

Male “After”

Female “After”

Close Voice Over Samples

The above audio was used for putting the foam through a tough test of absorbing the worst reflections the room could generate – recorded 18 inches away from the microphone. As we know from Tip #1 in this series, recording far away from a microphone in a room with poor acoustics gives you a LOT of room sound. So if we have no treatment on the walls, we need to get very close to the mic. Most people aren’t going to record from 18 inches away, so the above is maybe not your typical use.
So we recorded fairly close to the microphone (about 6 or 7 inches away) using the foam, and the “omnidirectional setting” on the mic (which we couldn’t use pre-foam due to how much extra room sound that pattern picks up) to demonstrate how good the foam allows our voices to sound now.

Male Voiceover With Omni Setting and Foam on Walls

Female Voiceover With Omni Setting and Foam on Walls

More Testing

After we conducted the above tests, we removed all the foam panels and decided to test the foam against another product, which purports to remove poor room acoustics in vocal recording. It fully encompasses a microphone with acoustic foam – you stick you microphone inside of it. Our goal was to play each sample in headphones, and NOT tell the person listening which sample was being played. In other words, it was a blind test.
We both chose the wall treatment foam as by far the best. In fact, not only did the other product not even eliminate the bad room sound despite completely encompassing the microphone. It actually made our voices sound worse – all muffled and unnatural.
The audio recorded with acoustic foam on the walls, on the other hand, sounded fantastic; no room sound and it actually made our voices sound better than usual. What was really happening was not that the foam “imparted” anything extra to the recordings, but rather it absorbed the undesirable room echoes and what remained was ONLY what should be there – our natural voices – with nuances and polish like we’d never heard.

Life Changing? Really?

So how did this “change my life?” Well, for one thing it will cut my production time by more than half of what it was. Without the foam, in order to reduce the amount of room sound in your recording, you have to get very close to the microphone (that was tip #1 in our series). But that results in a lot of p-pops, which have to be edited out (that was tip #5) after the fact. At least half of my vocal recording production time was devoted to editing out the p-pops! But now I don’t have to get close to the mic, so there are no p-pops.
Just that alone would have been awesome. But more than that, our voices sound better than ever. And we don’t have to fight our room anymore. We don’t have to set up bulky baffles or stuff the mic into anything. We don’t have to go into the closet. We get to use the room! Also, I can now use the omnidirectional and figure-8 settings on my microphone, which is pretty much impossible in a bad-sounding room because those settings make room sound even worse. This means we can record small vocal groups (try fitting THEM into a closet!), podcasts with multiple people using a single mic, and a lot of other things that were simply impossible in a bad-sounding room if you wanted the audio to sound professional.
So the final tip in the series is “try the new acoustic foam from Acoustic Fields.” It will basically make it unnecessary to employ any of the usual counter-measures to fight the room sound in home studios, making it easier and faster to produce great-sounding voice recordings.

Here is how to get started

Like I said, there are several brands of acoustic absorption foam. But one of the most popular and easily available is Auralex. Below (on the left) is a package of their 1-foot square panels to get you started:

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