Help! Subwoofer Newbie Problems!

Why not give JL a call? I’m sure they will help! BTW, turn your amps off and see if the sub is producing sound without your mains on!

yogiboy,

Unfortunately this is the last day I have to evaluate the subs before the return policy expires.  So that's why I've been frantic to try and diagnose these problems.  JL Audio won't be open today.

I would call them on Monday and let them know of the problems you have. I bet they will give you an extra day or two to trial. If they don't, send them back and find a pair of Vandersteen subs and xovers.
I guarantee they will work magic with your speakers.
Bob

gdnrbob,

Thanks.  Unfortunately I don't have flexibility with the choice of subwoofers.  My 2 channel speakers share the room with my home theater system, which is projection based.  I only have a limited area along the front screen wall to place a subwoofer, and they have to be as small as possible, otherwise they interfere with the projected image.  The JLs were the only high quality subs with the physical profile that fit my scenario.

The only other place I have for a sub is right behind the listening sofa, a few feet to the left of the listening position.  I'd be a bit wary of placing a sub there in terms of possibly localizing any of the sound.  Although I may try one of my two JL subs in that position, as placing two subs on a diagonal in a room is supposed to be a promising way of evening out room modes.

Little update:

I managed to get sound happening to the subs via my pre-amp outputs (turned out to be stupid user error.  I had to crank the output level of the subs far more than I imagined vs using the high level inputs).

Some listening yielded these results so far:  Dynamics didn't seem obviously restrained as with using the line level inputs.  However, there was still a real change to the tone, darkening (though also expanding of soundstage).   I love, love the tone of the Thiels and don't want that messed with.  I tried using only one sub and that seemed to split the difference - gave some of the recognizable Thiel tone back, plus some of the expansiveness of the sub.  Though back and forth between one sub and no sub had me thinking it was hard to decide which I liked.  The "best" tone seemed without a sub. 

So I'm still trying.  If I can get the good things I hear from adding the sub (added richness, bass depth, soundstaging) along with keeping the general character I love about the Thiels, that would be great.

Next step is to try the hook up most recommended for subwoofers: using a crossover to split the signal to mains and subs.  My JL Subs have a crossover, but because they are in a different room down the hall from my pre-amp/amp, that cabling is a nightmare.  I'll have to buy some additional 30 foot interconnects to test that out.

My plan has been, ultimately, to use a high quality analog outboard crossover.  Having spent a bundle recently on a great turntable (Transrotor Fat Bob) the last thing I feel like doing is digitizing everything with a digital crossover. 

Research showed that the crossover that fit my criteria best is JL Audio's CR-1.  It is very highly lauded for it's transparency and combination of flexibility and intuitive controls for seamlessly dialing in subwoofers with mains.   But...it's super expensive!  It would be over $5,000 Canadian.

As luck would have it, while working late last night I perused Audiogon and spotted a CR-1 that had literally just been listed that night....for $1,800!  The best price I've ever seen for a second hand CR-1.
I pressed "buy" as fast as my fingers would move and snatched it up.
Yay Audiogon!

So now I'm waiting on that to arrive.

If I feel I need to further tweak the subwoofers to the room, I'm not averse to the idea of only running the sub signal through some EQ/DSP.
To that end, I actually picked up a second hand Velodyne SMS subwoofer integrator.  A litte old in the tooth but may come in handy.
I've also been looking at the DSPeaker Anti-Node.

But...one step at a time.