Well now I know how bad the original speakers are. I think all six could be replaced with two new 10" woofers and two horns (Foster OEM, from a Zenith SS console).
The good news is the cabinet is low and long with the speakers in separate chambers, allowing for fully enclosing the rear and adding a tuned port or insulation.
Both 10" woofers sound pretty bad when the bass boost is on, which is to say "boomy". Turning up the treble brought very little in fidelity, so either the two 4" mids and two 3.5" cone tweets are shot. It cant be as simple as a crossover cap
.
This console is worth the effort mainly due to its solid-built walnut cabinet, 2g record changer and quality electronics, now restored.