The Freesound Project web site is a Free Culture sound repository similar to OpenClipArt for illustration, Project Gutenberg for text or the Prelinger Archive for film. Launched in May 2005 in Barcelona by the Music Technology Group of Pompeu Fabra University, it quickly attracted contributors and an audience from around the world.
Freesound is a sound repository rather than a music or audio repository. It contains samples of noises rather than of music or spoken word recordings. If you do want music there are several excellent music sites elsewhere on the Internet, from an artistic point of view notably Sal Randolph's OpSound. But these focus on completed tracks rather than raw sound materials, and are limited to music. Freesound has no such limitation.
Digital recording technology is so cheap and of such high quality that recording found sound or sampling musical instruments is easier than it's ever been before. But to record that sound you must have the experience to do so and you must have access to it. Setting up the right recording conditions for water going down a plug or travelling to a location where wolves are howling will be beyond the ability of many otherwise capable individuals. Freesound means that you can share whatever sound you can find or produce and access sounds that you could not even think of recording yourself.
The sounds on Freesound are amazingly diverse and imaginative. The first samples that I chose randomly from links on the front page were of tin cans being hit and of office background noise. There are musical instruments among the samples, and sounds that could be used musically, but there are also many more sounds that you probably didn't imagine you would ever hear recorded. Clicking the "Random Sample" link in the navigation bar at the left of the site can be quite addictive.
Finding pre-recorded samples to use in music or as sound effects in multimedia or film used to mean a trip to the library or a larger record shop to dig out the few sample or sound effects CDs that were hidden somewhere past the spoken word section. Or paying for floppy disks and later CD-Roms to be posted to you containing files that might or might not match the sound evoked by their description in the catalogue.
Freesound makes finding samples so easy that it feels like cheating. The samples on Freesound are usually very well tagged with keywords that describe the sound they contain, and even those that aren't have descriptive titles. Searching for a subject or a theme will provide you with many samples to choose from.
If your search doesn't find an existing sample and you really need the sound you can make it and then give it to Freesound so that others can benefit from it. That's how projects like Freesound grow. You will get more back from Freesound than you put in, and what you put in will make that true for other people as well.
It's easy to search or browse samples, users and tags on the site. You can see how samples have been remixed and re-submitted to the site, a feature pioneered by the Remix Reading project but taken further with Freesound's tree-view interface to that data. And you can discuss or request samples in the forums. Freesound has a very rich ecosystem of data and social interaction.
Any samples downloaded from Freesound are free to use - you are not restricted in how you use them and you don't have to pay for the privilege. This is guaranteed by the samples being licenced under the Creative Commons "Sampling Plus" licence.
The Sampling Plus licence has some problems for the use it's being put to by Freesound. It requires that you credit the original sample's author, which could become burdensome if you're using more than a few samples. The Sampling Plus licence is meant to apply to samples taken from a larger work, not to samples used to make a longer work. And it's unclear how the resulting work can or should be licenced.
Ordinarily at this point I'd explain how wonderful copyleft is and recommend the Creative Commons Attribution-Sharealike licence instead. But that wouldn't solve the problem here, as Attribution-Sharealike still requires attribution and is probably stronger than Freesound wants or requires. So I think the ideal licence for Freesound would be the minimal CC Zero. Don't be put off by this largely theoretical discussion of Freesound's current licence, but do remember to observe its conditions.
Samples in Freesound's library can be tagged with words in the same way photographs or web site addresses can be in other systems. Searching on tags rather than just titles can be useful for both human and software users of the site. It enables you to search conceptually or evocatively rather than searching for a literal description of the sound you are searching for. Sounds can also be geotagged, adding the latitude and longitude at which the sound was recorded so you can search for sounds by location as well. These facilities open up new possibilities for sound art, augmented reality and machine learning.
As well as its web-based interface there is a software API for Freesound that allows you to access the library from software programmed in C++, Pure Data and Max/MSP. This is a great resource for generative art, live coding and VJing. The C++ API can be used in systems such as OpenFrameworks or wrapped by an interface generator such as SWIG for use by other languages.
Part of what the promise of the Internet has come to be is the availability of a wealth of cultural raw material that would be impractical to assemble and distribute if it had to be accessed (and paid for) physically. This is not cyber-utopianism, although it does rely on at least some individuals having enough enlightened self-interest to contribute back to projects that they use. Rather it is something that the Internet makes possible and worthwhile.
Freesound realises that promise for sound. Browsing it is inspirational. Whether you are a sound artist, multimedia designer, animator or just curious to see what kind of noises there are in the world (an idea that will sound a lot less silly after a few minutes browsing the site), Freesound is a creative gold mine. Its breadth makes it the Wikipedia of sound, a basic resource and utility to refer to and build on creatively for anyone who needs sound for their projects.