Convolution Reverb
Reverb is everywhere, whenever we hear a sound we also hear echo's from the reflections of the source sound reaching our ears. This allows our brain to interpret room dimensions and position the source in the space around us. In music production we have digital and analogue reverb units and plugins that allow us to recreate this affect.
(Nave, 2018)
Understanding that every space reverberates in its own way means when recreating spaces in audio this must be taken into account. For the short film I am currently working on we are recording a lot of ADR. This means I will have a lot of clean audio without any room information. To put these clean audio recordings into their appropriate context is where convolution reverb and impulse responses come in.
Convolution Reverb
"Convolution reverb takes an input signal (the sound to be reverberated) and processes it with the sound of an actual or virtual acoustic space to create the illusion that the input was recorded in that space." (Lainhart, 2018)
In this example I will be taking the clean audio recordings from the studio, passing them through a reverb unit and recreating the space where the original recordings were created.
Impulse Response
"In the most basic terms, an impulse response (IR) can be defined as the time domain (time vs amplitude) response of a system under test (SUT) to an impulsive stimulus." (Rational Acoustics, 2015)
To put this in a simply an impulse response is a representation of the reverb signature of a room. For this project I used a speaker to generate a 20Hz to 20kHz sine sweep and recorded the result.
There are 2 different locations in the film I am currently working on and both rooms IR needed to be capture here are the results.
Location 1:
Location 2:
In Action
Here is a video on how I calibrated my impulse responses for the up coming short film I am working on.
(Doctor Duck, 2018)
For more information on convolution reverb here is an amazing article that is well worth a read.
References
The Audiopedia. (2016, October 4). What is IMPULSE RESPONSE? What does IMPULSE RESPONSE mean? IMPULSE RESPONSE meaning & explanation [Video file]. Retrieved from https://www.youtube.com/watch?v=t6zPF-2UEbA
Doctor Duck. (2018, March 31). Point & Click Impulse Response [Video file]. Retrieved from https://youtu.be/brJQo_4-GZc
Lainhart, R. (2018). What is Convolution Reverb? Retrieved from https://ask.audio/articles/what-is-convolution-reverb
Nave, R. (2018). Reverb. Retrieved from http://hyperphysics.phy-astr.gsu.edu/hbase/Acoustic/reverb.html
Rational Acoustics. (2015, June 22). What Is An Impulse Response? - ProSoundWeb. Retrieved from https://www.prosoundweb.com/channels/live-sound/what_is_an_impulse_response/