The Frequency Band Splitter is located in the Multitrack view under the Effects Menu. To begin, select and highlight your file. Go to Effects>Frequency Band Splitter. What this enables you to do is to separate your audio into user-definable bands...so, whether you want to do simple low-Mid-hi, or more complex lo-loMid-Mid-HiMid-hi, you have up to 8 individual bands that you can set.
Let's start with something simple, say, three bands. The crossover field is where you determine the cut-offs. So start with a figure of 120. You'll notice that the first field now states a range of 0Hz-->120Hz. Click on the "3" radio button, and then in the crossover field, type "4500". Now, you'll see that you've selected to use 3 bands, with ranges of 0-120, 120-4500, and 4500-22k (max range determined by the sample rate you're using)
When you're done, click OK. Audition will now extract these bands as individual waves in the multitrack, and insert them in a consecutive manner, below the original wave. Each file will also have the name of the original and the frequency band that it represents.
It's really that simple. Once the files are 'split' multitrack, you can add compression, limiting, reverb, EQ or any other effect and only apply it to the band that you desire. This also makes auditioning of multiband real-time processes (ie, adding a limiter to the low end only) very simple, seeing as you can just 'SOLO' the appropriate band and really hear what's happening, without having to mute or disable other bands in the process.
Now, this is one simple way to use the Frequency Band Splitter. Obviously, there are many uses. Of course, if you simply want to do something like multiband compression, but would rather work off one file in the MT view, simply click on the FX tab. Go into the effects rack and add three instances of the Dynamics Processor. Click Apply and OK. Inside the DP window, there is a Band Limit tab. This tab allows you to do essentially the same thing as the FBS's crossover field. Designate which bands you want to effect, type in the cut-offs, and you're ready to roll.
