Ears EQ is an audio equaliser for Chrome.
You could use the extension as a simple volume control by moving your mouse over the middle line until it's highlighted, clicking and dragging. This may give you more volume than you'll get with regular computer and browser controls.
Clicking the "Bass Boost" button instantly delivers a deeper bass sound.
Of course you can also use Ears as a graphical EQ. Start playing audio somewhere (the developer claims it works with any audio on any site), click the Ears button and drag the dots to reposition the filters (see the screenshot for an example).
If you like what you're hearing, save it as a preset for easy recall later; if you don't, click Reset to start again.
You can also turn Ears off for some or all tabs in a click or two, handy if you've changed sites and the previous settings don't work any more.
Ears had no effect on a few of our test sites, but delivered excellent results everywhere else, with its graphical interface offering very fine control over our audio.