Vandersteen 2C contour controls +-

So I have recently changed cables between my pre amp (ARC SP4) and amp (ARC VT60) and it made a significant difference: more detail and a better centered soundstage. But I lost quite a bit of punch in the low end. I like the effect of the new cables enough to keep them in.

If I want to use the Vandersteen contour controls to get some of the low end back do I dial it down... or up?

I’m assuming turning the bass contour down will lower the crossover point, effectively getting more from the low end.

Is this correct?

those are pads for the mid and tweeter
the crossover points are fixed and worried over with hand matching and tuning to drivers in a anechoeic chamber
i would let the cables break in for a while
then download the free vandertones and get an inexpensive analog radio shack spl meter and see what is happening with bass in your room
the 2 has an acoustic coupler with the back wall so you want to hit sweet spot of coupled but not so close you pump up bass and destroy image depth
check your setup using the excellnt math based approach in the Vandersteen manual

+1 tomic601.

 I had to position my 2Cs 9.5" from front wall to back of speakers, measured at the floor, with tilt-back the tops are 8.25" from front wall. No toe-in. Acoustic treatment on all walls plus ceiling restored soundstage depth and width. All rooms are different. Mine are also 7' apart measured tweeter to tweeter. Until I got them that close to the front wall I had almost no perceptible bass. Now. Bam! Nirvana! YMMV.

Thanks all. I do have these placed in the sweet spot and used the Vandersteen manual to get there. They are off the back wall about 23" and are equal side to side. With my old interconnects it sang. With the new interconnects I get more highs and sparkle in the center which is what I want. I just lost the low end somewhat. I can still hear it, it just doesn't have the bass impact I previously had.

I'm purposefully avoiding mentioning the interconnect brands involved because I don't want to get into a cable choice discussion. Both are premium brands and both perform well in this system, just somewhat differently.

So this might be a placement issue now that the interconnects have changed? 

I'm still unclear however - does lowering the bass contour (-db) push more signal to the rear facing coupled driver? Or does going +db on the contour add more to the low drivers? Or if the bass is not there it's just not going to be there regardless of the contour settings?

I can play around and listen but I'm more interested in the theory of how the contours are supposed to work.
The contour controls on the back of my 2Cs are for cut/boost of mid and treble only. No affect on the bass as far as I can tell. 
The only thing that restored bass in my situation was positioning the speakers differently.

Gotcha. Ok that makes sense now. I am going to try adjusting placement rather than expect an effective solution by just using the contour controls.

Thanks a bunch!
+1 for Tomcarr.
The dials do not affect lower frequencies.
As another poster mentioned, let the cables break in. You'd be surprised how much they might change.
You are very welcome. Be patient. Keep us posted...

PS- call John Rutan (Audio Connections)  @ (973) 809-4467. He is extremely helpful. He was the one who suggested I get mine a foot or  less from the front wall. 

@hifiman5   I have a complete set of ARC Litz Link cables with ARC Litz Line speaker cables. I am swapping in a used pair of Cardas Hexlink Golden 5c between the amp and pre amp and I love the sound improvement. I'm pretty sure just a slight repositioning and I'll have what I'm after.
now I get why Richard is terse...
the pads on the back do NOTHINg to bass
they adjust by 3db the tweeter and mid
the most excellent manual explains this....

i used Cardas for years....take a bit to break in, take more than a bit for the dielectric to form and also be very careful not to put preload or said another way a kink in the natural bend radius of the cable...
also a careful read of the manual shows the coupler is a pretty low frequency animal...
so are you lacking low low bass or .?

I was getting damn near full range with the current placement - so yeah - it went really deep with the ARC cables.

I've AB'd them 3-4 times now over a week and I definitely prefer the magic that happens with the Hexlink cables. They do show a lot of bass but they whiff on the deep deep stuff. And that "whiff" is very much what was happening when I first got the Vandersteens and didn't have the placement correct. I could hear them trying but didn't get the resonance.

I don't tune for tons of bass but if I have a system that is capable of it I should be able to make it happen when the recording offers it.

They currently are about 26" out from the rear wall and 31" from the side walls and 105" apart (measured from the center of the top cloth).

I'm going to:

A. Try them closer together with the ARC cables with the same distance from the rear wall to perhaps center the imaging and get better detail to my listening spot.

B. Try moving the speakers back into the corners a few inches with the Hexlink cables to try and get the bass back but keep the center sparkle that happens with those.

I'll you know what develops from that!

As you move them closer to the front wall, try unequal distances from the side walls (the centerline of your listening position will not be in the center of the room) by a few inches. This asymmetry will help even out problem bass modes.

FWIW, I've gotten the best sound from my 2Cs with these dimensions:

(All measurements from tweeters)
Distance from front wall-12.5"
Distance from left wall-30"
Distance from right wall-40"
Distance between speakers-84"
Distance to ears, (measured perpendicular to plane of speakers)-120"
All walls and ceiling have acoustic treatment

I agree with most of the speaker placement dimensions, but isn't the 12.5" a little close to the front wall? Wouldn't this close to the front wall make the soundstage a little shallow? Just wondering.
Rooms are all different in character, so one man's 12.5" may be 3 feet in another room. Another Vandy owner (ctsooner) had his Quatro's placed pretty close to the walls by JohnnyR. It didn't seem like it should work but it did. 
OP, let us know what you find.
I spent an evening moving and listening with the new cables... only to return to the exact placement where they were before. 6 months ago when I purchased the speakers I labored over placement and apparently I found the right spot for them back then.

26" off the front wall and 31" off the side. Exactly 9 feet to the listening spot on both. For the record, this is exactly where the Vandersteen manual "odd dimensions" placement would put them in my room. Length of the room, width of the room divided by 3,5,7,or 9. I tried them all and then some.

No toe-in, no angle back (I have the 6" stands so the tweeter is at ear level when seated.) Speakers are level and square. I tried them toed and angled but it was not as good. Behind the speakers are built-in bookshelves and record storage, full of books and records side to side, no gaps.

The 12.5" from the wall didn’t work well for me. But I have 16 feet in front of them to fill with sound. I could see how that could work in a shallower room.

I think letting the dielectric settle with the new cables is the right advice for now. I’ll post back in a week or so once I stop changing cables and just let it ride for a while. It sounds really good, but I realize I’ve been chasing an unknown spectre!

Thanks everyone for the interest and help.
Looking back at your original post, perhaps the new interconnects between the amp and pre might be holding back on the lower frequencies?
I agree, let the dielectrics run in for a while. Sometimes, they just open up like a flower.

Good plan to let the cables burn in. Amazing how different your system can sound after 400 hours or so. Glad to hear it sounds really good now, and the best is yet to come!
@mr_m, the room treatments made all the difference in where the speakers could go. My problem was not enough bass (and I'm not a bass freak), so getting close to the front wall yielded better, smoother, more even response at the listening seat without any "one-note bass issues". Because of the treatments, the soundstage actually increased in all 3 dimensions. I've heard, and now am a believer, that the room will dictate 50% of what you're going to hear.

Funny thing - I had never considered inside space to be important but I removed two very full LP crates from between the speakers and the amps (amps are positioned in center between the speakers) and that opened up some more bass. So the speakers need a little breathing room on both sides, not just between the wall and speaker.

I'll be keeping the new cables in place between the pre and amp. =)

On side note: The single most effective jump in sound quality I've observed - once I assembled my current set of components - was power purification and AC cables. I can't explain in words how huge of an effect that made (noted: I have an old house with dated wiring). AC upgrades should not be shrugged! If I hadn't made those upgrades I don't think I would be hearing such large differences in interconnect cables.

Thanks all!

change your outlets on the wall
PS Audio makes a nice affordable outlet or a hospital grade Hubbel is even less $
also get the amp and preamp on seperate circuits
try a ground cheater or two but absolurely ensure the power amp is grounded if you do
finally get all your wall wart switching supplies, digital hash producers on a third circuit

It sounds like, all things being equal, the Vandersteen 2C models - with back firing woofer, need to be placed closer to the front (or back behind them) wall to amplify the bass. I experimented with my 2Ci model and moved them from 24" to 16", considering mine are on the sides of a bay window, and it shrunk the depth of the soundstage but did add a tiny bit more bass. Just like everything else, it all boils down to tradeoffs. For me the presentation of the soundstage is more important than the extra bass.

After letting the cables sit without change for over a week the bass came back 80% which is fine - I was a little bass heavy before. More importantly, it really only shows up after letting the entire system warm up for a few hours. Previously I'd get up to full range in an hour or so.

I've now put a bit shy of about 200 hours on the cables.

I think this lends to the dielectric properties theory. The new cables are just more difficult to charge than the other ones. The end result is a better sound in my system.

That is great to hear. I bet when you hit 400 hours, things will be even better.
Alternatively, perhaps the mid and treble controls are turned up too high in relation to the bass at any given sound level.  Their relative setting to the bass may have changed from the old to the new wires.

I've set the contour controls on the speakers at 0 during this time.

I don't use tone controls on the pre amp at all and I'm not inclined to. They are bypassed entirely.
I have the 2Ci, on their original metal stands (the ones with the T shaped foot). The quote below is taken from
I drive them through other vintage, Harman-Kardon Citation 17s pre-amp and 16As amp, and original Monster cable - the ones the size of a garden hose. So I run tweeter +1 and midrange -1 as suggested below.

"I found a touch of lift in the high treble (tweeter set to +1dB) to be necessary to counteract the speaker's slight lack of off-axis air; this has to be balanced, however, against exaggerating the excess of HF energy above 10kHz. Though this might then be thought to leave the midrange a little depressed, I nevertheless found -1dB on the midrange control to give the optimal balance between the need for sufficient high-midrange energy and not to unduly emphasize the speaker's uneven response in the same region. This will be different for every listening environment and system, however. "