Sansa Fuze + 10 Band EQ patch = Awesome...

[saidin43]

Disclaimer: I am not a programmer\developer.  I was able to follow the well written instructional posted on patching a build of RockBox and compiling for my platform.  I did not create the patch, someone was kind enough to write a patch to allow for more bands, and I made use of it.  It's located in the patches section.

It works well
Installed on: Sansa Fuze 8GB.
RockBox Build version: 88cda7em-120201

Why I did this...
I have a 2010VW Jetta, and due to the placement of the component tweets, I was getting some terrible harmonics from the windshield.  I also needed to boost in the low to mid range to compensate for road noise.

The default 5 channel EQ wasn't quite enough, since it included the low and high shelf filters, effectively leaving me with 3 actual bands I could use for my purposes.
I also didn't want to spend the money on a dedicated hardware EQ & wiring, and would have required a line driver, which can lead to audio quality problems...

Results:
I am currently cutting 4 EQ bands and have 2 .5db boosts.  I am not using pre-cut, but am using ReplayGain.

Battery life seems to be around 7hrs with 6 bands, but I have not measured scientifically.  I did use 8 bands at one point, and did not have any problems with skipping, but did not test battery life.

The audio quality in the car has improved significantly.  I couldn't listen to some music due to the "screechy" nature of some of the instruments or notes.  Aside from screechiness, audio sometimes sounded flat.  Note that this is with uncompressed music, so I am not compensating for mp3 compression etc.

Bottom line:
I wish the 10band EQ was at least an option that could be unlocked instead of me having to patch RockBox.  It sounds great, and hasn't impacted my battery life enough for me to worry.  If you know how to use an EQ, this makes RockBox an extremely powerful little tool for fantastic audio quality, especially in an Audio hostile environment (car) 

Just wanted to give my 2c.

Thank you RockBox Devs!