The bass note is actually right on spot, everything is in tune - both the guitars and the bass hit the same D flat.
Hitting that note higher on the bass would probably make the whole thing sound a bit weak and wouldn't work in that context. Lower, well I'd need a 5 strings. Plus, the guitars and bass need to come together at that particular point.
The bass all by itself works relatively fine - nothing unusual. Same for the guitar - I mean there is a bit more energy/resonance on that chord, but it's not unless you combine both bass and guitar that it all goes woooomf.
Because that D flat sounds a bit fuller on the bass and the guitars have more resonance in the low mids.
I have a hi pass on the guitars set at around 120 IIRC, and a dip in the bass somewhere between 120 and 200. That was the best "compromise" to make room for both and that balance works well for the song - but for that one chord.
But the more I think about it, the more I realize that the song probably calls for spot automation, structurally speaking.
The verses are very sparse and consist of drums, bass, and a harpsichord - so the bass needs to fill quite a bit of space to glue everything.
The bridge and chorus are much more dense - bass shifts to 16th notes, the double bass drum pattern kicks in and the guitars - 4 tracks of hi gain stuff.
Actually, it's almost surprising that I managed to find a basic static EQ set up for the bass which would (almost) work throughout the song. :s