5mm LEDs have a saturated ESR of around 16 Ohms, so it will introduce some unless you buffer it from the supply or have a large power Amp ( not <<1W intended for ear buds). THey also are rated at -5Vr absolute max, so back to back with a power Op Amp that can drive the current you want is advised.
A Gain>x10 with diode compression feedback or a log Amp will give the dynamic range you expect since LEDs have a large threshold voltage from 2 to 3 V and your eyes and ears are logarithmic but linear current vs brightness characteristic of LEDs ... is obviously not logarithmic. 2~3 decades of voltage range would be what I would look for, but you may be satisfied with just blinkin' lights.