- mc’s formula is a rip from Floyd Toole’s book, the focus of which is setting up a home theatre, not a HiFi. Read the book and find that the mid wall location works for rectangular rooms. Not all room are rectangular.
- 80Hz XO and no main roll off is a sure recipe for a mono low end which is fine if you like it. Lots of level, no detail. mc’s Moabs claim 20Hz. Adding 4+ subs from 80Hz is going to create one hell of a bass bump.
- Floyd states that DSP & EQ can get perfect bass in one location only which is my preference.
- Phase matters and is both audible and measurable.
Distributed Bass Array configuration
Please, I don't want to debate the merits of the DBA nor of those who espouse it. I am considering adding two more subwoofers to a system that has two already. To those who use a DBA,I am interested in how you have configured them, specifically--
- Do you run in mono, or do you split the array to run in stereo?
- What is your approach to setting phase (delay) among speakers that may be facing different directions and are different distances from the listener?
Showing 8 responses by ieales
I hope a sub with a continuous phase control will work well enough.Nope. "All-Pass phase controls operate at only a single frequency with varying degrees of shift across the passband." see http://www.ielogical.com/assets/SubTerrBlues/PhaseControl.png at ieLogical SubterraneanHomesickBlues for an image of how a continuous phase control functions. |
1Hz XO resolution on subs and mains is nice. Sub and mains may not necessarily crossover at the same frequency and more than probably at different slopes. I often imagine that DBA is a lot like what happened in a mastering lab in the LP days: After listening to glorious 2 channel bottom end in the studio, it got sucked down to mono below 40Hz. And these guys recommend 80Hz w no XO on the mains. Surely you jest? |
Lastly, your main speakers will sound much better if you high pass them at 80 than at 40 Hz.Depends on the room, main, sub and processing available. My mains are -3dB @ 31Hz measured pseudo-anechoic. ≈40Hz integrates better than 80Hz. When I used Spica TC-50, ≈90Hz. The clarity obtained by LF attenuation in the mains with good subs should not be ignored:
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It seems to work well almost regardless of how the subs are laid out. Geddes, a DBA progenitor, has several pre-conditions before the above statement is true. For a simulation comparison of the effect of moving DBA subs in a room and system similar to the claimants, see http://ielogical.com/Audio/misc/DBARoomSim.php |