The final aspect of a room’s sound (at least for our purposes) is the room’s reverb. Our purpose here is to color the room as accurately as possible with an estimation of reflections after the initial reflection. Depending on how fast or slow those reflections occur and their constancy, we can have either an echo (long reflection times), reverb (short reflection times) or some combination of the two.
Let’s look at out reverb module:
With some variation, these are the basic settings for most reverb modules. Some are much more expansive. Others only include a delay time. Still others only include presets (which aren’t going to do you much good if you’re trying to build for yourself. Avoid these like plague since they are rarely accurate or intuitive.) I’m using Adobe Audition’s basic reverb.
Pre-delay time: These are your early reflections, as calculated in the second part of this series. If you use the delay like me, leave this at zero. Otherwise, you can enter your calculated pre-delay here.
Diffusion: While I use diffusion, I rarely calculate it. The idea is that diffusion is based on the shape, size and contents of your room. If a wall is flat, there is going to be relatively little diffusion. If there are lots of materials of different sizes and shapes (like a library wall lined with books), diffusion is going to be higher as it changes how the sound is reflected around the room.
Perception: This covers how absorbent or reflective your space is. In general, EQ covers most of this, but you can use the perception slider to adjust for more metallic rooms(reflective), rooms with more curtains (absorbent) and anywhere in between.
Decay: I saved this one for last, as it requires the most care. This is your bread and butter in the reverb module.
A room’s reverb is measure in terms of RT60. That is, the time it takes for a sound to fall 60 dB. You can do the math if you want… but there’s no reason to, since we have the interwebz to calculate for us. I typically use this calculator as it gives multiple values for different frequencies. That said, for most purposes the calculated values for 1000 Hz should serve most purposes.
Enter you dimensions and go! If you want to add elements such as windows and doors, the calculator will take those into consideration as well.
For our 10 x 10 x 8 room, I got an RT90 time of 1.46 seconds or 1460 ms.
Set your wet to 100 and your dry to zero.
Trust trust trust trust trust your math. Resist the urge to over reverb a space as it will make your room sound empty and your voices sound hollow and far away. You can bump up your perception to give things a little more dramatic reverb, but to keep things natural, don’t over-saturate your sound.
There it is… your room is set:
