Old Library Studio Podcast

So today I’m going to start off-loading some of the really neat stuff that I’ve discovered in the last several months. At the absolute top of my list is Sonicbirth, which is a program for Macs which you can use to program your own audio and midi effects. Of the features I’m most excited about, the ability to do realtime convolution is hands down the most valuable/useful.

What does a free realtime convolution plugin mean to me ?

Well, aside from the fact that I have been searching for a free convolution effect for years… and that commercial convolution effects are very expensive…

The most common use for convolution is to create a convolution reverberation effect. In essence you can use an impulse generator (e.g. a balloon that you pop, or a cap gun, or a animal training clicker) to record the Impulse Response (IR) of any acoustic space (e.g. a concert hall, your bedroom closet, the backseat of a car, a trashcan, a cardboard box). This Impulse Response (IR) captures all the information about that acoustic space you need to create a virtual version of that concert hall (or closet, or what-have-you) in your computer.

When you convolve the IR of the real acoustic space with your digital sound recording, the result is a sound recording which takes on the acoustic properties of the real acoustic space.

For myself and the students at Old Library Studio this is really good news, because we have found that the reverberation effects that come with the software we use (Digital Performer) leave a lot to be desired. They just don’t sound very good. We could spend hours just trying to get a good mix, fighting how bad the reverbs sound… sometimes we have resorted to using three or more bad reverbs blended together ! Now, with Sonicbirth, we have a better alternative.

It gets better.

You might ask “But, wait I don’t have a concert hall or a balloon, or a nice microphone, or a portable recording device. How do I get the glorious/bizarre Impulse Responses I need ” ?

The good news is there are plenty of free Impulse Responses on the internet. Everything from highbrow Opera Halls and sitting rooms (the teatro de scala in milan, 18th century french salon) to the everyday (some guy’s livingroom in amsterdam,the inside of a eurovan).

You don’t need to have a fancy Digital Audio Workstation, or be an engineer to reap the benefits of this great software… Sonicbirth creates Audio Unit plugins, and the software comes bundled with a bunch of example plug-ins, including a couple called “convolution reverb” which will allow you to start experimenting with convolution right away. That means you can actually start do convolution tests in Garageband !

Then it gets even better. It really would have been enough to just have the sounds of great concert halls and average livingrooms, but there is so much more that can be done with convolution !

Impulse Responses are useful for modeling more than just acoustic spaces, you can also use them for electrical systems, and digital systems. You can model Speakers, Amplifiers, even very expensive pro-audio equipment (like compressors, microphone preamps, and fine mixing boards, even EQs).

The good news is that there is a great selection of free IRs from classic pro-audio equipment on the web.

Where to get free Impulse Responses on the web

Voxengo

Voxengo has IR Reverb packs, with some really great sampled spaces. This is where to go to get the Teatro de Scala in Milan and the French Salon. If you are a fan of secret societies, they even have a Masonic Lodge.

Noise Vault Impulse Responses

Noise Vault is a really great IR resource. With acoustic spaces, and classic proaudio gear samples.

A collection of IRs from Finland

Some nice concert halls, sampled with a lot of attention to detail (binaural mics, various spaced pairs,etc.)

Prosoniq’s IR collection

Some nice IR packs organized by the size of the spaces. Small, Medium, Large, etc.

A collection of HRTF IRs from IRCAM (impulse responses that can make it sound like something is behind you, or above your head )
IRCAM is a french acoustics, computers, and music research place.