Chris
So just a question.
Bass waves are slower than all the others. So why do people put subs X feet behind their mid and tweeter drivers ? Just asking.
If I was you Harry I would be very tempted just "temporarily", to set up in near field for one hour - just to hear what was possible with one sub.
I’m not exactly shure what this would mean? More upfront placement = faster bass?
Placement is a question of "allowable" phase angles between drivers caused by offset drivers (specially in distance to the listener). As long as this offset phase angle is not far off, there is no "real" problem.
Bass waves travel at the same speed as any acoustic wave in air, but have longer wavelengths, so offset distances in the low bass can be considerable without being audible. Usually it’s said to be desirable to be below 90 degree - I’d keep it lower, to be on the safe side in the cutoff region where the subwoofer is still emitting considerable upper bass levels.
At 40 Hertz xo this would still be 67cm for a quite tight max. 30 degree difference. This results in an allowable 120 degree two octaves above, at 160Hz, at eg. -24dB (for 12 dB/oct.)
But I agree, that close-field placement is the preferable "error", because a) the excursion / level of the subwoofer can be considerably lower, b) the decrease of room reverberation level relative to the direct sound level should reduce audible room resonances & bass colorations = c) the modification of the subs frequency response by room resonances drops an order of magnitude.
But... it works only if there is no spurious midrange energy exiting reflex tubes or coming from the driver. Still - the lower sub levels reduce distortion and "box talk" & "cone cry", both help.
