OK, so after spending about 4h yesterday testing the SB12 in different locations, audio sources and settings, I wanted to share some initial findings. After some testing, I'm crossing over at 80Hz but am consciously keeping my RP280Fs set to large by choice and running the sub mode on +main. I bought them for their awesome mid-bass (for music) and after testing that back and forth, I get better overall results that way, even when crossing over at 60Hz instead.
Sub positioning:
1. In either of two available positions in the rear sound-stage, the single sub can be localized even at lower input volume or gain. It didn't blend well, even when changing it's firing direction and positioning. Having two of them in the rear might have worked but I found that more distance really helped with blending.
2. This became apparent first when I picked a spot for it on the right long wall halfway between MLP and front stage. Better blending but it could still be localized. Because I had to crank up volume and gain, at that point I was starting to think that the sub might be too small if placed in the front stage area due to the distance.
3. Wrong. The front right corner further improved blending but due to the room shape and ceiling slope, I could still locate the sound coming from the right a little too much, albeit from the walls. Room gain was good there but I didn't like that the bass sounded muddy (even with playing with the adjustments).
4. Left front corner, front firing: bingo. Here, the sub starting blending in well and "disappearing". I played a little more with positioning and the input volume and gain but settled on this location:
Sound output relative to input volume & gain:
At 0.0db for the sub channel and with a single RCA cable into the left channel (not the LFE input) on the sub, I initially got no bass at all. (My stop gap receiver is a Denon AVR588). I thought something wasn't working.
Cranking up the channel volume on the amp a good bit and the sub started playing. With both input volume and gain up there is plenty of peak power to rattle the entire house but it certainly wasn't sounding very good.
Here's where I get the best results, by far for music: I play the sub channel at 12db going in from the amp and the gain set to about 40%. This produces very clean, dry punchy bass and the notes in different bass tracks across various genres are reproduced nicely. With lower input volume and higher gain, I get muddier bass. I generally play with overall Treble and Bass set to 0.0db) - Very happy with that result. (Not saying a ported sub wouldn't give me an equal or better result but the concern that the SB can't deliver for music in this size room is not my observation at all. At that point, just turning the gain knob one or two slots over, the SB is pumping out more well blended bass than I'd ever want. At that point it sounds as if I was playing with +4db bass in tone control.
Movies: Pleased to report that the selected position gives me similarly pleasing results. Clean bass, deep and loud enough for our taste. Again, not to say that a PB12 wouldn't delivery better results but the reality is, I found that the PB12 would have been too large in size for the location options I have, anyway. Let alone the spousal acceptance factor. I also will note here that I even ended up bringing the input volume down to +9.0db in Dolby Digital for a better balance. At 12db (same gain on sub) and moderate master volume the bass was too much compared to the remaining speakers, albeit still well blended.
Additional notes:
Sitting down in the 4-5 available seating spots in the MLP area (~20ft away), the sound is very good now. However, once you stand up in the, the bass becomes clearly less audible. So the lower frequencies seem to be floating around the lower elevation. I'm going to play around with elevating the sub in it's current position to see if that affects this and potentially reduces the audible difference in bass between standing up and sitting down.
Summary:
- In a room like ours, you definitely need 2 of these subs IF you're playing in the rear and are forced to have the unit relatively close to your ears due to localization issues.
- The front stage was a far better location for the single sub. As it blends so well in the left compared to the right, I'm assuming that the weird room shape actually helped blending here. Ceiling above the sub is 16ft high and 10 on the side of the room)
- The higher the input volume relative to the gain level, the cleaner and dryer the bass was. In it's location at those settings, the SB12 blends well and reproduces bass very nicely across different genres of music, exactly what I was looking for.
- For home theater the results were equally satisfying. I actually had to reduce input volume by 3db in Dolby Digital because bass was too loud relative to the rest of the frequency band. (And with signal compression already set to medium BTW!)
- In my case, setting the FL/RL speakers to small did NOT produce better results but they are large speaker able to aide the SB12 in reproducing a lot of sweet mid-bass where I felt the sub alone, perhaps in conjunction with bookshelfs might have fallen a bit short in a room my size.
My main takeway: I'd love to hear a PB12 in the same spot for a back to back comparison but don't see a need to upgrade at all. Would I get flatter response in the deepest frequencies? Of course but as mentioned above, I don't care enough about the 1-2 minutes total during most regular movies where you get sound at those frequencies to pay more and then deal with the issues that come with the additional size. To fit the PB12 where my SB is currently sitting, I'd have to move my left RP280 and probably the entire TV stand which would result in that being off center.
Hope this helps someone else in a similar situation.
