Looking for the "better sub"

Robbob

>>Considering all we make of tiny differences in gear and tweaks we make, I find it astounding that anyone even suggests that low level inputs in as good for 2 channel listening<<

I gather you are fairly new to audio reproduction, higher end audio, dipole speakers, and subwoofers in general (mostly a lot of reading?).

As time goes on, and you gain more hands on experience....you won't find things quite so astounding...or, absolute.

BTW...I saw a picture of your room at another forum (very nice looking). The curtains covering the wall behind the Maggies are a bad idea though. The rear sound wave is your friend (it's there to help you), it should strike a live wall...and not heavy curtains.

Dave

ROBBOB, here is why I disagree with your stance on high level inputs. I have TRIED both on a very high quality sub ( Wilson Benesch Torus) which allows for both connections and the difference was not noticable. Some people prefer using balanced outs from the pre because it allows direct feed from the pre without the added DISTORTION from both the cables and the amplifier. The low level preamp feed is always purer. There is no significant time delay. If you want to talk about significant group delay ( which is very noticable ) try integrating a sub without infinate phase control. This is a much more significant real world issue. If delay is of concern to you make sure that the subs grill is in the same plane as your speakers. An alternative to infinate phase control would be an active crossover with true linkwitz/riley (24db slope in both directions with -6db at the crossover which eliminates phase issues.) The problem with discussions like this and the conclusions which are drawn is that most people have not actually tried both methods and believe instead in some companies hype. High level inputs are not necessarily a bad thing its just that good sound depends alot more on other issues and I for one would not choose a sub based on the input philosophy.

"After trying both hook-up methods, I'm always a little surprised when someone claims they are the same."

"(Using line-level inputs), on top of that the signal is transmitted over a different type of cable."

I didn't claim that line-level & speaker-level hook-ups sound the same. While admittedly I haven't compared both in a wide range of systems, it's reasonable to expect varying results with different preamp & amp designs & types. As the OTL advocates will say, the performance of transformer-coupled tube amps is attenuated or colored at the frequency extremes. A good illustration is the Jensen Iso-Max coupling transformer that I use in the connection to my subwoofer. The windings are optimized for deep LF use and roll off significantly above 1000 Hz. Doubtless compromises are made in the deep LF performance of some transformer-coupled amps, in the interest of obtaining linearity across a wide spectrum. Some amps are more effective than others with extension & coherance in the sub-bass region.

While it's tempting to believe that speaker-level inputs are better because the sub "sees the same signal" as the main speakers, one must also consider the main amp's performance in the sub-bass region. And lest we forget, the tonality of the subwoofer's SS amp affects integration, whether through line- or speaker-level inputs.

In my system, at least, using a direct-coupled preamp notable for good LF extension & control, the sub sounds faster and more articulate through at the line-level input. Based on rave magazine & forum reviews, I suspect JL chose to omit speaker-level inputs for reasons other than cost. However, it would be nice to have both approaches available to satisfy everyone.

BTW...I saw a picture of your room at another forum (very nice looking). The curtains covering the wall behind the Maggies are a bad idea though. The rear sound wave is your friend (it's there to help you), it should strike a live wall...and not heavy curtains.>>>

Dave, I'm hardly new at audio. I've owned everything from B&W to Carver Amazings and tiny yet lovely Royd Coniston R's. I started off with Canton Quinto 540's many years ago and I still remember choosing them over the far better Frieds! Those Cantons were just too cool when I was in my 20's.
Of course nothing is absolute, but I've heard enough high-level vs. low level comparisons to make it fairly obvious one is "often" best. Does that mean someone's system isn't working better with low level? Not at all.
As for my room and curtains, it's best I've ever heard from a pair of 1.6s. The 120" screen provides just the right reflective properties, while the curtains at the side trap unwanted reflections. The result is an insanely deep soundstage which amazing focus on vocals. The room (via sheer luck) ended up being an ideal space for the systems.

Anyone wanting to see what's up....click on these...
http://ghostlight.zenfolio.com/img/v3/p3696847-5.jpg
http://ghostlight.zenfolio.com/img/v3/p268388597-5.jpg

Cheers,

R.