On my Denon 3805 when in stereo the fronts are highpassed at 80Hz and the sub lowpassed at 80Hz. However, when in direct the fronts are not processed (full range) but you can still engage the sub - this would no longer be a flat response as now you have an overlap between the sub and mains.

I only use Direct / Pure Direct when listening at lower volumes or when the music doesn't need the sub. Generally I miss my 20Hz SVS bass too much to run without the sub for long.


M60s, VP150, QS8s(3), SVS PB12-isd, Denon 3805, Emotiva UPA-7