Canyon Soundings: A free outdoor impulse response library

[cthonophonic]

A voice came to me on the wind and whispered that the people are clamoring for a deeply-sampled desert canyon. Who am I to deny the will of the masses? After much clamor, clamber and clangor, I present to you Canyon Soundings, my submission for KVRDC26.

Canyon Soundings Overview with Site Markers.jpg

It consists of 51 impulse responses (as 48kHz, 24-bit stereo .wav files) that can be loaded into your convolution software of choice. If that software happens to be Audiothing's Fog Convolver 2, you're in luck, because I've also included a bank of true stereo presets that you can access by copying the Canyon Soundings folder into your Fog Convolver banks folder.

You'll find more specifics on the Canyon Soundings product page, but the general idea here is to capture the reverberations of sounds placed far away, out of view, and off to the side in this complex landscape.

As shown in the colorful illustration above, there are 13 sites spread out along the bottom of a small canyon, and the microphones are placed a bit back from the edge, looking across the canyon. For most of the sites, there are four separate impulse responses, recorded with the speaker facing in four different directions. The reverberations of a sound facing away will sound noticeably different from those facing back, or to the left or right. You can combine these to taste to create realistic true stereo impulse responses.

There are all sorts of wonderful IR-based reverbs for placing sounds in indoor settings like concert halls and scoring stages, but I don't think anyone has ever done this before with outdoor impulse responses, certainly not in this depth. Others, surely, have more sense than I do. Typically, outdoor IR libraries try to encompass as many different environments as possible, and if there are variations in source position within each space, they cover a few different distances, all straight ahead. While that is probably the most economical way to capture the essence of a space, I think that there's something special in the way that sounds change character as they move across the stereo field.

Sounds do get weird and wild in rough terrain. Low frequencies diffract around obstacles. A sharp slap echo in one location will transform into an odd zip just a short distance away. Diffuse echoes seem to almost creep across the landscape. These impulse responses capture the idiosyncrasies and maybe even some of the specialness of the place. If a concert hall is designed to foster an idealized, reproducible acoustic experience, then a desert canyon is maybe the opposite that. But now, here, you have this endlessly reproducible, if not quite idealized, space at your disposal.

So what's it good for? Certain types of sound design? Certain types of music? Just noodling around? Yes, some (maybe even all) of these things! It's up to you. The license is CC0 - No Rights Reserved. You may use, modify and redistribute these files without restriction.

I posted an update yesterday, adding some labeled images for each site and slightly adjusting the start times of a few of the presets for Fog Convolver. I haven't been able to dedicate a lot of time to this project since release, but I plan to make a few updates over the next week. In the long term (that is, after KVRDC is done), I plan to record sweeps for a few new sites to fill in some gaps. These recordings will depend highly on the weather and wildlife conditions, so it's impossible to predict when that might be. For the near term however, here's my to-do list:

VIDEO
I need to make a video. It seems like this would go a long way in clarifying the "whole deal" of this project. I don't have much experience in this, but hopefully I can put together something acceptable while DC26 is still live.

4-CHANNEL WAVs (DONE!)
Some convolution software will only do "true stereo" with a 4-channel .wav file. The channel order seems to be consistent between the reverbs I've looked at (Convology XT, Waves IR1, and SIR 3), so these files should function the same for all of them. I view true stereo capability as one of the most important parts of the project, so I want to make sure that it will be easily accessible to all.

NEW FILE NAMES (DONE!)
I'm considering simplifying the file names by getting rid of the azimuth and distance, which are admittedly a little superfluous. The "degrees" character (°) appears to prevent Liquidsonics Reverberate from successfully loading any of the files, so I should rename them anyway in the interest of compatibility. I figure that if I'm going to do a potentially project-breaking change to the naming scheme (for anyone who used/created presets with the original file names), I might as well simplify them even further. The normalization value seems genuinely useful (at least I've found it to be a handy reference) when creating your own presets, so I'd keep that.

README
While the description on the KVR page is pretty comprehensive, I would still like to create a kind of manual/readme with more information, including some technical details that seemed like a bit of overkill to include on a product page.

I hope that you have the time to give it a try in this year's crowded field of great KVRDC entries. If anyone has questions, suggestions, words of praise, denunciations etc., please post them here.

Thanks, and good luck to all!

[cthonophonic]

I've simplified the filenames and updated the download to include four-channel .wav files, all of which I've confirmed to be working in Convology XT, Waves IR1, Liquidsonics Reverberate 3. I hope the changes in file names haven't messed up any existing projects too badly.

I also modified the normalization scheme of the Fog Convolver presets so that the Normalized and Tails presets are "site normalized." Basically, I adjusted the Output gains of all the IRs so that within each site, they have the correct relative amplitudes. Due to this change, a preset that is Angled Away will now, in general, be quieter than a preset that is Angled Back, for example.

If anyone has any issues with these, please let me know here.

[Ivan_C]

Thanks a lot for sharing them and for all the extra information provided! I love the idea, I can't promess they will be used on all my next productions, but I like a lot the concept. How long did it take for you to make all the recordings, and then all the extra post processing?