Hi everyone, Dennis Foley from Acoustic Fields. Today we're gonna talk about good reverb. Good
reverb, okay? What is reverb? We should all know by now, I hope, is how long a sound stays
around in the room after it's been sung, spoken, or played. Kind of overstays its welcome, if
we're thinking in more non-technical terms, okay? Stays around too long. What is reverb?
Reverb is really a measure of decay. It starts here and it goes here. This is where we want
it. This is where it starts and this is where we want it. So it's a measure of how long that
takes, how long that decay process takes, how long it stays around in a room after it's been
sunspoken or played, overstays its welcome. All of those things mean pretty much the same,
but this is the more technical side. What is the decay? What is the tail? Well, it's composed
of harmonics, right? Multiple orders of harmonics. That's what's in the tail. That's what's so
fun to hear. The tone and pitch, the tone and pitch are there too. So that's what you want
to hear. So decay is posed of the harmonics and the multiple orders. We want the fundamental
maybe in one order of harmonic in our critical listening room. You know, if we have to look
at what we're getting versus what we need, that would be a good way to look at it. So in order
to do that. we have to mess with the reflections because that's what's causing it. When we think
about reflections, I want you to think about absorption immediately for treatment. Diffusion
is another option, but it's very limited in its usage generally. It's very limited in its
usage in small room acoustics, but very powerful. But you got to kind of know what you're doing.
So 90% of the time, when you think of reverb, you're gonna think about absorption for treatment.
So we need some reflected energy in our rooms. We need that input from noise in our environment.
We need that, you know, distance. If you walk and talk towards a wall and you get closer
to the wall, you'll be able to sense that you're getting closer because of the reflections of
your voice off the wall. So we need that. We need that to help us localize, kind of help
us determine our spot in the world, if you will. Anticoag chambers. are reflection-free environments
by definition. So they're not something we want. I've been in one. I made it about 20 minutes.
I couldn't take it any longer. Because without that sensory stimulus, you start to get headaches
and it disrupts you. So you don't want it. Reflections or localization, I think the process is called
spatial recognition. That's what we go by. So science of psychoacoustics. Now, quadratic
diffusion is another technology that we can use for reverb. Now, how does it work? Well,
it helps us with non-localization. Excuse me, let me give you an example in our studio in
California. Our ceilings were nine foot, two dimensional quadratic. We put people in listening
chair, we blindfold and play a few songs. First question, how far away is the ceiling? Now
remember it's nine feet, 11, 12, 13, got a guess one time of 15 feet. See, and that's what diffusion
does. It kind of breaks up a big reflection. This is a simple, and it puts it in a lot of
smaller reflections. So it's less easy for our brain and hearing mechanism to detect the time
signature, the decay of those. energies and that helps us determine distance. So it's hard
to, it's also hard to determine distance overhead. We're way better side to side front to rear
than we are overhead. So you ever see people looking up at the sky trying to find a plane,
you know, and they're always looking, they're always looking at the sound, you know, well
the plane's ahead of the sound, right? So you have to keep that in mind. It's a process and
what diffusion does is it busts that process up. and it helps with non-localization. It's
good in our multiple channel rooms. It's good in our two channel rooms. It can be really
good in a vocal room sometimes. It can be really good in a live room a lot of times. So it has
its benefit, but it's one technology that'll help us. So absorption and diffusion are the
two technologies we use for reverb. So reverb is good and bad, but we need it, but we have
to manage it. Hope this helps. Thank you. Thank you for watching this video and if you liked
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so that'll help you. Thank you.