Episode 75 - Acoustics w/ Unf*ck Your Studio
Show Notes:
Live with Matt Rad - Episode 75
Dec 14, 2021
w/ Unfuck Your Studio - Week 1
Ruairí O’Flaherty and Spider ‘Ron’ Entwhistle
Show notes by: Bradley Will
What We Do:
Ruairí:
Acoustics serve a higher purpose, and if it’s done right you should never have to think about it again.
They’re not something that you actively think about or engage with or interrogate. It’s more of a canvas on which you can paint. Something you can trust.
A room should allow you to follow your artistic impulses without being afraid that you’re going to mess up when it translates to another listening situation.
Do it once if you can, and the best that you can.
Great speakers and great rooms tend to disappear and leave us feeling connected.
Spider:
When you’ve got technical questions in your mind and people aren’t on the same page you can get into toxic levels of doubt when in a session because people are not hearing the same thing in the room.
We get into this to eliminate doubt in the process
Our approach is to get to the essence of what the person is trying to do and then tailor-fitting the result to their exact needs.
We’re less interested in acoustics, but more into art and creativity and the well-being of the client and community. The acoustics is a means to get to arrive there.
Q: What is the ideal room acoustically? What are the ideal elements?
Spider:
We get a lot of calls from people who are looking to convert a room in a house or a garage.
You want to be on the ground. You want to be on concrete. You want a 10’-12’ high ceiling if you can because you don’t want your head to be halfway between the floor and the ceiling where you’re hitting destructive room modes.
You want to be symmetrical in between the side walls so that you can get get the L/R imaging.
Ruairí:
Our first question is, what is the room for? Is it for collaboration? For scoring? For mixing?
If you can limit your use-case and know exactly what it is you want to optimize you can make very smart trade-offs and make even a small bedroom work well in at least one location in the room.
The ideal room (for a producer) is one that’s comfortable and gets out of the way. One where the song, the art, and the collaboration is the focus.
You want an even frequency response. Not one with a lot of peaks and dips.
What you DON’T necessarily want is a flat frequency response. You want the low end to rise at the bottom.
You want a 6dB rise towards the bottom from the very top frequency down to the bottom of the range.
When we say flat we want a rising bottom-end. That is what’s going to sound most contemporary.
The Time Domain Response (TDR) is almost always left out of the conversation.
What happens to sound when it leaves the speakers and enters the room?
In a room the ideal time domain response is longer, but it’s an even, gentle, rise
You don’t want certain notes ringing for a long time.
This is at least as important as the frequency response and probably more
TDR needs to be controlled.
A lot of people haven’t experienced an ideal room before.
Q: How do I make bass sound good in a small space?
Ruairí:
Bass is everything when making a room.
You can use off-the-shelf acoustic products like GIK to treat the midrange and highs, but not for the bass.
These aren’t actually bass traps.
4” thick panels are never going to do anything to the bass.
Once you get close to boundaries, the air doesn’t move anymore.
As you approach the boundary in a room the sound is now carried by air pressure instead of by air velocity, and mineral wool doesn’t do anything to absorb air pressure.
Mineral wool panels work great at highs and midrange, but at low frequencies on the boundary you need a different type of absorber to manage the bass.
We use a lot of limp-membrane absorbers.
GIK sell some off-the-shelf versions.
They’re big and custom made and relatively expensive, but they’re the only thing that will actually absorb low-end near a boundary and give you that sense of tightness.
We approach small rooms by accepting that we can’t absorb or afford to absorb the low-end energy.
We put the speakers and the sweet spot and the client couch in a place where the low-end is best behaved. In typical rectangular room this is fairly predictable.
Room Modes:
Every room has natural resonant frequencies where the notes are going to be boosted or cancelled.
These are generally very predictable in common concrete rectangular rooms.
You get a boost in energy near the walls, and usually a dip in the center of the room.
Typical 8’-9’ ceilings are going to have problems at 70 Hz.
The typical seated person has their head at 4’ high off the ground. RIGHT in the middle of the vertical mode.
We try to create some sort of acoustic symmetry where we can.
If there is a doorway to one side we try to bring in gobos.
If you can’t do anything else, get yourself a good ceiling cloud.
Mineral wool
Over the first reflection point and the speakers.
It’s critical to place it at the halfway point on the ceiling between the speaker and the listener.
Make sure you’re filling it with Roxul or something soft and appropriate if you make it yourself.
A cloud is a soft absorber 4”-6” deep. We usually make them 5’-6’ in width and length.
Installing the cloud at an angle to the ceiling is not ideal. At most have a 4” kink but no more than that.
The lower the cloud is the better it performs and encroaches on your space.
On an 8’ ceiling we’re putting the cloud at 7’ in order to reach and touch it.
The farther we can get the cloud off of the ceiling the better it will work.
If we can get it a foot off of the wall in a small room that’s a win.
A 6” cloud with 6” of air behind it is almost as good as a 12” thick cloud. We can use the air gap to our advantage in this way.
Speaker Position:
Spider:
Our goal is to separate the perception of the speakers and the room so that they’re not perceived as one combined sound.
We want to tame the room reflections in a way that’s balanced and musical.
A room that’s too dead is uncomfortable to be in for more than 5 min.
It takes a musical approach to be able to recognize when certain frequencies are egregious.
Ruairí:
Always put speakers against the wall. There’s almost never a situation where the speakers need to be off of the wall.
The ideal place for speakers to be is in the wall.
Speakers don’t radiate in a direct way, except at the very highest frequencies.
As you go down in frequency that “cone of light” of frequency gets broader and broader until its radiating like a sphere.
By putting the speaker at the boundary, the energy that would normally wrap around the speaker is immediately reflected in a way that reduces the negative phase cancellation that you’d normally get when the rear-energy is reflecting off of the rear wall with a greater delay.
We try to position the listener somewhere between 1/4 and 1/3 of the length of the room, in order to dodge the nulls from room modes.
Spider:
You have to get the height of the speakers correct so that your ears are between the tweeter and the bass driver.
Your ear height should be between the tweeter and the bass driver on a two-way.
There’s a little room for preference on the height placement.
Q: For those who are starting out, how can you train your ears to know what’s good?
Spider:
You try to learn a room and compensate for everything that’s wrong with it.
Ruairí and I have both the experience and the reps of listening in a consistently great situation for years.
You can learn a lot of things online, but acoustics and studio design don’t seem to be one of them right now. There’s not a lot of real expertise out there. A lot of it is misleading and incomplete. It’s more like superstition or norms or common ideas that don’t actually work.
Without the access of being exposed to world-class sessions you’re on a very slow growth curve. It’s the exact same thing with acoustics and studio design.
It’s almost near-impossible right now for someone to go to the internet and figure these things out.
Q: Should I have a subwoofer?
Ruairí:
If your low end is being cancelled because of room modes it doesn’t matter how much energy you put into the room.
Maybe what you need is not a new sub, but a new speaker that can produce that low-end in the first place.
Ask if you can afford a speaker that will add the low-end you need without a sub.
Phase is not a binary. You can be in-phase and out of phase at different frequencies at the same time.
It’s very hard to phase-align a sub.
It’s usually best to buy a sub from the same manufacturer because they will integrate more easily.
I’d rather have a pair of cheap subs in the right place than one good sub in a compromised position.
