BioEQ for Rockbox is a fascinating EQ setup designed with the iRiver H140 originally in mind. The files have been given to me, FLACvest, by HiFlight. I first heard of this EQ from Dr. Xin Xin’s Cool Talk massage boards back in the day when Head-Fi was new and I was trying to figure out what the heck an operational amplifier was.
I have since adapted BioEQ to sound good on the Sansa Fuze; I suspect it will do wonders for iPods and other devices.

     The key feature of BioEQ is the design of the low shelf; peak filters 1, 2, and 3; high shelf filters, their Q (the breath of attenuation or amplification on a particular frequency), and their gain or amplitude. BioEQ aims to work with the Floyd Munson curves or reflections in the human ear. BIoEQ is not about hopping up the bass on weak headphones or smoothing out the treble on some peaky headphones; it is about making the headphones you plug into the port of your amp or DAP work with the natural reflections inside the human ear.

     The inaugural work has been completed. A variety of EQ configurations (.cfg files) have been generated. Some configuration files have different levels of bass attenuation, a flat equalization, and another designed to replicate a speaker, or the natural, sound the human ear hears without headphones. BioEQ is about taking advantage of the incredible equalization that only Rockbox has offered in the portable music player.

     These setups are also available as .eq presets for the Electri-Q DSP for MediaMonkey3. It has changed the way I listen to music. I want to share that with all of my fellow Rockboxers, MediaMonkey-heads, and Head-Fi’ers.

Here is the information you need right now for the inaugural distribution prepped for the Sansa Fuze v.02 hardware:
I've added rockboxAsAnApplication.apk for Galaxy S Phones (T-Mobile Vibrant) into the mix with a new release of one, the .apk, the instructions on a blog post over at amot (Any Manner Of Things), and some new EQ Presets, all released today, 02/21/2011:

The BioEQ.rockbox project is an effort to bring excellent equalization to the Rockbox community. You can email the head developer, FLACvest, at with tips, tricks, inquiries, and issues. The first symposium on the BioEQ project will be held at the Head-Fi “Burn-In” event, February 19th, 2011. This event will hopefully showcase some distribution media, or at worse pamphlets with a MegaDownload address to grab a distribution of the tweaked .rockbox folder and EQ configuration files.

Here is the result of the inaugural effort. About three years of work have been poured into these EQ files and I just learned how to edit the global configuration files to apply all mods globally; how redundant! However, it will spare you from getting the basics set up.

Here is the address of the first BioEQ.rockbox distribution.
The target is the Sansa Fuze v.2. The creator, FLACvest, is not responsible for any loss of data or property damage incurred by using these files.
The location of the Updated BioEQ Files is on Mediafire: <--- this *.zip archive is for dumping into your <root>/.rockbox/eqs/  folder in your Rockbox setup. <--- this *.zip archive is segregated into seperate subfolders for each EQ Set. This allows you go organize the EQ Sets, and only copy/paste the ones you're interested in into the <root>/.rockbox/eqs/   folder in your Rockbox setup.
The location of the Updated rockboxAsAnApplication.apk for Samsung Galaxy S is on Mediafire:
NOTE: I'm sure by now there are MUCH fresher builds of RAAA available, however, this one works on the Samsung Galaxy S Model T-959 Vibrant. Leaving the *.apk available just in case anyone is interested.
After Installation of the EQ's a few settings need to be modified before the full BioEQ setup is complete.
BioEQ Setup:

Sound>Sound Settings>Channel Configuration>Custom
Sound>Sound Settings>Stereo Width>55%
Sound>Sound Settings>Crossfeed>
Sound>Sound Settings>Crossfeed>Crossfeed>Yes
Sound>Sound Settings>Crossfeed>Direct Gain>-4.5 dB
Sound>Sound Settings>Crossfeed>Cross Gain>-5.5 dB
Sound>Sound Settings>Crossfeed>High-Frequency Attenuation>-7.5 dB
Sound>Sound Settings>Crossfeed>High-Frequency Cutoff>1100 Hz
Sound>Sound Settings>Equalizer
Sound>Sound Settings>Equalizer>Enable EQ>Yes
Sound>Sound Settings>Equalizer = Here you have to save a text file and name it as "BioEQ.cfg" in a text editor more at the end of the tutorial
Sound>Sound Settings>Equalizer>Precut>0.0 dBSound>Sound Settings>Equalizer>Simple EQ Settings * ignore these, handled by "BioEQ.cfg" file
Sound>Sound Settings>Equalizer>Advanced EQ Settings * ignore these, handled by "BioEQ.cfg" file
Sound>Sound Settings>Equalizer>Save EQ Preset> * ignore
Sound>Sound Settings>Equalizer> Browse EQ Preset > * ignore
Sound>Sound Settings>Dithering>Yes
Sound>Sound Settings>Timestretch>No
Sound>Sound Settings>Compressor>Threshold>-24dB
Sound>Sound Settings>Compressor>Makeup Gain>Auto
Sound>Sound Settings>Compressor>Ratio>10:1
Sound>Sound Settings>Compressor>Knee>Soft Knee
Sound>Sound Settings>Compressor>Release Time>1000 ms

If you want to make your own equalization file, it's as easy as following the steps below. On Windows I find editing the *.cfg Preset files easy with Notepad++ (be sure you change the filetype extension from .txt to "all files" and include .cfg at the end of the filename if using this program to modify *.cfg files for Rockbox.

The "BioEQ.cfg" file should be a plain text, nonwordwrapped file that looks like this: starting at the # and ending at the 0 in 60. Cut and past that into a text editor, like Notebook on Windows, Gedit, Kedit, or Mousepad on Linux, etc and copy it to a file named simply: BioEQ.cfg and place it in the .rockbox/eqs/ folder on your Fuze. ENJOY YOUR MUSIC!!! Best, -FLACvest

# .cfg file created by rockbox r28351-101024 - eq enabled: on eq precut: 0 eq band 0 cutoff: 40 eq band 1 cutoff: 220 eq band 2 cutoff: 2500 eq band 3 cutoff: 7500 eq band 4 cutoff: 16000 eq band 0 q: 35 eq band 1 q: 45 eq band 2 q: 30 eq band 3 q: 31 eq band 4 q: 30 eq band 0 gain: 60 eq band 1 gain: 1 eq band 2 gain: 64 eq band 3 gain: 14 eq band 4 gain: 60