Deciding an EQ's Center Frequencies I am currently making a relatively simple EQ of a music app, for which we decide to have 5 bands. Other than that, we want to have a bass boost knob, which, as I view it, is just another Peak EQ filter — so a 6 band EQ. 


Are there any standards on what a 5(or 6) band EQ's frequencies should be? 
What should the bass boost's frequency be?


Also, we are making only one Q knob to control the Q for all bands, simply because there isn't any space left for more knobs to be added, but we still want to provide this functionality. 


Is this a good practice/design?
If not, is it at least acceptable or useful?
The audible range is about 10 octaves, and usually the center frequencies of a graphic equalizer would be distributed equally spaced on a log scale to cover that range. Common equalizers have either $30$ bands (with $1/3$ octave filters) or $10$ bands (with $1$ octave filters).

If you want $5$ bands, you could choose filters that cover approximately $2$ octaves. The five center frequencies would then be something like

\begin{matrix}
30\,\text{Hz} &amp; 125\,\text{Hz} &amp; 500\,\text{Hz} &amp;2\,\text{kHz} &amp;8\,\text{kHz}
\end{matrix}

If you have an equalizer like that I'm not sure if an additional bass boost button makes much sense. If you want $6$ frequencies, just divide the $10$ octaves into $6$ equally spaced bands (on a log scale).