A nice find by Pro Tools Expert: Isol8 by TB ProAudio is a free multiband mix monitoring plugin that lets you quickly isolate five custom frequency bands, either by using its mute or solo buttons.
- Five adjustable frequency bands
- Solo/mute buttons for each frequency band
- Solo/Mute Buttons: shift-click deactivates all other buttons
- Linkwitz-Riley crossover filters, a "parallel combination of a low-pass and a high-pass L-R filter." Click the link to the Wikipedia article for reference.
- 24/48dB/Octave filter slope
- Multiple filter channel modes (Stereo/Left/Right/Mid/Side)
- Multiple monitor modes (Stereo/Left/Right/Mid/Side)
- In-place or centered monitoring
- Adjustable output level
- Volume dim button for mixing at lower levels
- 64-bit internal processing
See Isol8 at work in this short demo:
OS X: 32/64 Bit VST, 32/64 Bit VST3, 32/64 Bit AU, 32 Bit RTAS, 32/64 Bit AAX. You'll need Mac OS X 10.5 or newer.
Download Isol8 here. No signup or email address required.