Monday, August 1, 2011

Guide: How to setup and use the equalizer

Setting up the equalizer
To setup what type of equalizer you want, go to the equalizer preferences (Preferences -> Audio -> Equalizer)

Number of bands: Choose anywhere from 2-10 bands.  A band represents a range of frequencies that you can adjust the gain for.  Each band will add more cpu processing, so only choose the amount you need.  5 is a good number to start with. 

Quality:  GMMP includes 3 different DSP filters that can be used by the equalizer.  To simplify things, each filter is associated with a different quality setting.
-Default (Recommended):  This is a RBJ Bi-quad filter.  The quality is good, but it has the worst freqency response out of the 3.
-High:  This is a 1st-Order Butterworth filter.  This has a much better frequency response, so gain adjustments to one band will have less effect on adjacent bands.
-Highest: This is a 2nd-Order Butterworth filter which has a very good frequency response.  This is very CPU intensive (around 6+ bands on an HTC thunderbolt results in the audio skipping)

The Equalizer View:

The quick nav bar should now contain and equalizer button.  Click on that to get to the equalizer view pictured below.
At the top you will see the preset spinner.  This will show the current preset (or flat if none is selected).  Under that is a status indicator showing whether or not the EQ is enabled.  Under that is the preamp bar.  Which will adjust the overall gain of the audio.  Finally under the preamp is each equalizer band bar.  This area is scrollable if all the bands cannot be displayed at once.  Above each band the center frequency and gain is displayed.  Each band can be adjusted from -12 decibels to +12 decibels.  Changes to each bar will not take effect until you release the bar with your finger.

Menu Options:
Pressing the menu button will bring up a bunch of equalizer specific options.

Toggle EQ:  Toggles the equalizer on and off

Save Preset:  This will save the values of pregain and each band to a preset.  Simply provide it a name and it will show up in the preset spinner.  Note: A preset is specific to the number of bands, so you cannot use a 10 band preset on a 5 band EQ.

Delete Preset: Will bring up a list of all the presets.  Chose whichever you would like to delete

This post will be updated as more equalizer features are added.