Ok gurus, I just got done pulling the trigger on an ICBM to help solve some real bass management issues in my system. From what I have read, this is just the piece to do it. I need to get some advice and this may be quite long, so please bear with me. First off, here is the audio portion of the system:
Adcom GFA 5500 (Mains)
Adcom GFA 6000 (Center & surrounds)
Adcom GTP 830
Energy C-9 (pair Rf & Lf)(freq resp. 31Hz-23Khz
Energy CC-1 (Center)(freq. resp 50hz-23Khz)
Proficient C640 (rears in-ceiling)(freq resp 32Hz-22khz.
HSU VTF-2 (coming soon!)

I currently am not using SACD or DVD-A formats. The marantz DVD is connected digitally. The GTP 830 only has 3 preset bass management levels: 1. all large, sub on, 2. Large mains, rest small, sub off, 3. All small, sub on. The sub crossover is 100hz and I really don't want to lose the amazing abilites of the C-9 by crossing them over at 100hz. The ICBM will be integrated between the Pre/pro and the two amps and the speakers will presumably be set to "large" with the sub "on". Here is the problem. With an analog stereo input, there is no output to the pre/pro sub out jack. I want the benefits of the VTF-2 in two channel stereo mode using line level inputs. Can the ICBM be configured to output redirected bass to the sub that is not LFE input, while still maintaining a LFE hookup for DD and DTS inputs? I think it can, and that is what convinced me to buy it. After reading the manual, I am still a little fuzzy. I think the LR recombine will have something to do with this. Can someone confirm this as well as give me some hookup and XO setting advice? Don't be afraid to get technical. I have full calibration capabilities using AVIA and a SPL meter and a lot of time on my hands!

Thanks in advance,
Eric

The ICBM already has you covered -- you will have even less to do than you think to use the VTF-2 in stereo mode. Assuming that the mains will be set up for a crossover point in the ICBM (in other words, not set to "bypass"), the low frequency material from those channels will always be redirected to the ICBM's subwoofer output -- even when the GTP 830 is in stereo mode, with its subwoofer output idle.

How I would approach this setup: set all speaker channel delays in the GTP 830 to zero (either 0ms or 0 feet, depending on how they are presented in its menu). Set the 830's bass management to all speakers large, subwoofer on. Switch the sub mode to mono since you only have one sub. Switch the sub lowpass control to normal (unless any HSU sub users around here recommend the steeper 36dB/octave filter). Set L/R recombine to "off" (setting it to on will make the mains receive a full range signal, although if the mains have a crossover point specified there will still be a signal created from those channels for the sub -- resulting in a "double bass" situation that may or may not bother you). Set the left/right channel crossover to 60Hz initially, although you might want to try 40Hz too. Set the center crossover to 80Hz, although you might also try 60Hz and 100Hz if you want. Set the surround crossover to 60Hz. These crossover values are loosely based on a rule of thumb several people around here recommend -- using a crossover point one octave above the -3dB frequency response for the speakers, or double the lower limit and use that -- but in my experience it never hurts to experiment with the crossover point a little. For example, my mains have a frequency response similar to your C-9's, and I have them crossed over at 40Hz in my 950's bass management.

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

Thanks for the timely response gonk, just one more question. When the VTF-2 arrives, will I bypass its crossover (assuming the mains are crossed at 40 or 60hz? If so, what should the ICBM crossover for the sub out be set at?

With the ICBM in place between the 930 and the VTF-2, I would bypass the VTF-2's crossover (or set it as high as possible if there is not an option to bypass it).

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review