DSP \ EQ help

im out of my depth here.....if i was building a very small BT speaker and wanted either custom gains\EQ settings to assist in making in sound bigger, is there anything small that i could consider?

i see there is some ability to modify the BT\AMp chips which have the CSR modules, just dont know much else?
I have studied the same thing, and understood that many commercial bt speakers use DSP to get bigger sound. Can't really say what exactly does it do, besides eq, but one interesting method I found, was psychoacoustics... by playing certain extra frequencies, you get an immersion of a "bigger" speaker.

Sure makes quite small DSP boards, and it can be programmed with Sigma studio. If I remember correctly, the program has something related to psychoacoustics. I have wanted to test it myself, but haven't got the time for it :(
A very old psychoacoustic trick is to deliberately distort signals that have a frequency that is too low to reproduce normally with a tiny loudspeaker, add the distorted signal to the original signal and high-pass filter the sum. When you hear some harmonics, you will also hear the fundamental, even when it isn't there.

Regarding filtering, you could build a Linkwitz transform circuit or other type of biquad to extend the bass response. A biquad can also be made with a DSP. The more you extend the bass response this way, the larger the cone excursions and the more (intermodulation) distortion the loudspeaker produces, so you have to find some compromise there.

Some small active loudspeakers have a non-linear filter that compensates for the non-linearity of the loudspeaker. That way you can extend the bass response and reduce distortion to some extent. I can't tell you much about this, as all I know about these techniques is that they exist and that analysing them probably involves Volterra series.