In case anyone with similar questions to mine Googles their way into this thread, I'll answer some of my own questions, based on obtaining an SVS SB-1000. Although I started integration of the new sub from scratch, my ideal blending ultimately arrived with the same crossover setting of just under 60Hz. Higher gain (1:00+ instead of 11:00), which seems to follow from a sealed versus ported design.
1) In a room full of acoustic compromises and listening strictly to music (90% rock or jazz), with a goal of hearing rather than feeling the bass at moderate volume, is a "good" subwoofer important, over a mediocre one?
As one way to investigate, I plugged in my old sub to my DAC directly, set the crossover to 40Hz (it's lowest setting--the SB-1000's is 50Hz), and played some tracks heavy with bass guitar. Although I read on a sound engineering site that bass guitar only extends to 60Hz and upright bass to 40, that seems wrong. I couldn't find any album without significant articulate substance below 40Hz. On Tony Levin's bass riff from "Don't Give Up," for instance, only the very highest notes rolled off vanishingly . My old sub was rated to 32Hz (-3dB), which gave virtually the same performance as the SB-1000 on "natural" bass (kick drum, bass guitar, upright bass), though the SB-1000 may have more definition even here on the very lowest notes, and has a superior tone--I want to call the SB-1000 Darth Vader's bass amp. But, for tracks with augmented bass (synthesizer, for example), there is obviously a plain difference between a 24Hz rating vs. 32Hz rating. "Welcome to the Machine" became a different experience with the SB-1000, there were also low-level room ambiences I didn't know were there on various tracks. Meanwhile, hip-hop,Erykah Badu's _Badduizm_, and Brian Eno's _Another Day On Earth_ obviously contain notes a 32Hz sub can't even find. If I weren't consciously searching for bass tracks, my normal round of rock and jazz is served 95% equally by both subwoofers, save for the fact that the very lowest tones are much juicier through the SB-1000. That juiciness, unfortunately, doesn't quite match the tonality of my Dynauido X12s at their bottom edges, which is noticeable once in a while in ways that didn't occur on my older sub. Current solution there is currently to turn the sub down more, which is a shame.
In all, I've been surprised at how much low-level content there is on a wide range of music, however, which can benefit at least to a small degree from lower extension.
2) Is high-passing the Dynaudio X12s at 80Hz preferable to running them full range with the sub crossing in at a lower frequency? I was able to experiment with this by connecting the SB-1000 to the DAC and then running another patch cable to the amp. After volume-matching and readjusting the crossover to 80Hz, I could switch between the highpassed setup versus full-range plus 60Hz sub crossover alternatives by turning some knobs and switching DAC outputs between RCA and XLR.
Unfortunately, other variables get in the way here. When running full-range, I normally use XLR inputs. These seem to sound better to me than an rca connection from the DAC, either because of cabling or XLRiness or delusion. But plainly, when adding the subwoofer's electronics into the chain, I at once liked the bass more (probably because 80Hz let in more juicy tone) but I liked everything else less. It lost some of the dimensionality, which may be a matter of noise floor, or may be a matter of losing the continuity in the X12's midrange driver.
What I can say is that "relieving" the X12s and my amp of the loest 20Hz didn't improve anything enough to overcome the barely-perceptible limitations of cabling or added electronics. Too bad I don't have the option of trying XLR from DAC to amp direct, plus amp-controlled variable crossover to the sub (e.g., a "normal" setup). But I love my class D integrated amp, so my current setup is quite a good balance of compromises. Nor do I regret the new sub, particularly since it sits directly below the shelf unit that holds my mini-components and so occupies effectively 0 space.
1) In a room full of acoustic compromises and listening strictly to music (90% rock or jazz), with a goal of hearing rather than feeling the bass at moderate volume, is a "good" subwoofer important, over a mediocre one?
As one way to investigate, I plugged in my old sub to my DAC directly, set the crossover to 40Hz (it's lowest setting--the SB-1000's is 50Hz), and played some tracks heavy with bass guitar. Although I read on a sound engineering site that bass guitar only extends to 60Hz and upright bass to 40, that seems wrong. I couldn't find any album without significant articulate substance below 40Hz. On Tony Levin's bass riff from "Don't Give Up," for instance, only the very highest notes rolled off vanishingly . My old sub was rated to 32Hz (-3dB), which gave virtually the same performance as the SB-1000 on "natural" bass (kick drum, bass guitar, upright bass), though the SB-1000 may have more definition even here on the very lowest notes, and has a superior tone--I want to call the SB-1000 Darth Vader's bass amp. But, for tracks with augmented bass (synthesizer, for example), there is obviously a plain difference between a 24Hz rating vs. 32Hz rating. "Welcome to the Machine" became a different experience with the SB-1000, there were also low-level room ambiences I didn't know were there on various tracks. Meanwhile, hip-hop,Erykah Badu's _Badduizm_, and Brian Eno's _Another Day On Earth_ obviously contain notes a 32Hz sub can't even find. If I weren't consciously searching for bass tracks, my normal round of rock and jazz is served 95% equally by both subwoofers, save for the fact that the very lowest tones are much juicier through the SB-1000. That juiciness, unfortunately, doesn't quite match the tonality of my Dynauido X12s at their bottom edges, which is noticeable once in a while in ways that didn't occur on my older sub. Current solution there is currently to turn the sub down more, which is a shame.
In all, I've been surprised at how much low-level content there is on a wide range of music, however, which can benefit at least to a small degree from lower extension.
2) Is high-passing the Dynaudio X12s at 80Hz preferable to running them full range with the sub crossing in at a lower frequency? I was able to experiment with this by connecting the SB-1000 to the DAC and then running another patch cable to the amp. After volume-matching and readjusting the crossover to 80Hz, I could switch between the highpassed setup versus full-range plus 60Hz sub crossover alternatives by turning some knobs and switching DAC outputs between RCA and XLR.
Unfortunately, other variables get in the way here. When running full-range, I normally use XLR inputs. These seem to sound better to me than an rca connection from the DAC, either because of cabling or XLRiness or delusion. But plainly, when adding the subwoofer's electronics into the chain, I at once liked the bass more (probably because 80Hz let in more juicy tone) but I liked everything else less. It lost some of the dimensionality, which may be a matter of noise floor, or may be a matter of losing the continuity in the X12's midrange driver.
What I can say is that "relieving" the X12s and my amp of the loest 20Hz didn't improve anything enough to overcome the barely-perceptible limitations of cabling or added electronics. Too bad I don't have the option of trying XLR from DAC to amp direct, plus amp-controlled variable crossover to the sub (e.g., a "normal" setup). But I love my class D integrated amp, so my current setup is quite a good balance of compromises. Nor do I regret the new sub, particularly since it sits directly below the shelf unit that holds my mini-components and so occupies effectively 0 space.