Isolating sounds from an audio track

Shurakai

Hello all.

For a long time now I've produced music as a hobby, and one thing that has always escaped me was other artist's ability to use samples effectively, and isolate the particular sound they are looking for to the exclusion of all others.

For example, there is a horn making a neat sound, but there are troublesome strings playing a melody in the background that I would want to eliminate in order to use the clip as a sample. Another example would be the seemingly common act of isolating the human voice and stripping all other sounds.

After seeing technology that was designed to eliminate the vuvuzela sounds in live broadcast, this led me to guess that one has to fiddle around with the frequencies and such in order to isolate a particular sound, but I really don't know where to start looking in order to find out how to do it.

Any help you could provide would be awesome.

proXimity

You really can't do it effectively with just a stereo track mixed, it would be like trying to take just the banana parts out of a strawberry banana smoothie- you know it's there, but it's 100% part of a new thing now. The only reason the vuvuzela trick worked is because they played roughly one frequency (~235Hz), which is fairly easy to tightly notch out with an EQ while leaving most of the other frequencies unaffected. You can minimize other sounds' audibility with EQ, but you cannot just magically delete them.

The only way to get just one "part" (track) of a song to remix is to get the original multitrack recording... and good luck with that.

cooljammer00

Depending on the song, some bands let their stuff get remixed by giving out the audio stems.

Improvolone

You can also get a musician to play what you want and record them, but I do know a professional trumpet player so that it easier said than done for most people.

EggyToast

A lot of electronic musicians that dabble exclusively in sampled stuff get by through judicious use of EQ, and then when EQ can only go so far supplementing it with other sounds.

So if you have, say, a horn sound with strings underneath, you would use EQ to try to isolate the horns, and perhaps put a synth pad underneath as well to further cover the strings.

There is no "easy" way to isolate sounds in mixed music. The "vocal remover" or "vocal isolation" plugins/tools only function due to the fact that most vocals are mixed dead-center. In other words, it's a byproduct of production methods.

edit to add: here's a good example of how an electronic artist will "cheat" when it comes to sampling. Note how Amon Tobin uses flute, guitar, drums, etc., but how he will often throw a filter on it at the end of a measure. In the final song it sounds like an intentional effect, which it might be, but it also helps him cover up any other sounds in the sample and isolate the particular sound that he wants.

http://www.youtube.com/watch?v=lvNWkCbCLH0

So it's doing double duty. In a lot of ways, you need to start constructing an entire track with the "not so great" sample and then make it work how you want it once you have more than the skeleton up.

Vortigern

Lots of good advice in here. Like Eggy said, using effects to cover the bits that are less than perfect is a pretty common technique.

The other thing to consider depending on the type of sound you're looking for is to recreate it, or parts of it with a synth (hardware or software, your choice, I like soft synths for a bunch of reasons, but why limit yourself?). Create the tones from whole cloth and either mix multiple channels to get the final sound you want or if you're lucky just use the synth patch you created. If you're mixing more than one, it's probably easiest in terms of final performance to sample the mixed sound and then just use that.