ICBM and BW 600S2 Series...

Discussion in 'Archived Threads 2001-2004' started by Scott O'Keeffe, Dec 24, 2001.

  1. Scott O'Keeffe

    Scott O'Keeffe Stunt Coordinator

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    Santa is bringing an ICBM down the chimney, and I thought I'd pose some questions ahead of time.

    I will certainly listen to various settings and play around with it myself, but figured I'd pass along to see whatcha thought.

    The main reason I purchased was, of course, for DVD-A. Anything will be an improvement. Bass is virtually nil without the needed crossovers.

    I have a Panny RP-91 and 602S2's for my mains, LCRS2 center, and JBL HLS-610's in the rear. ASW100 Sub. I have a Denon 3300 which has a fixed 80HZ crossover for all channels.

    Frequency response +- 3 dbs is as follows:

    600S2: 52Hz - 20Khz

    LCRS2: 58Hz - 20Khz

    HLS610: 55Hz - 20Khz

    ASW1000: 25HZ

    I was wondering if setting the crossover to 60Hz on the outlaw would be pushing these babies a little to hard. I like the idea of letting giving my sub a little break for the lower mids. On the other hand, I wonder how setting the xover to 100Hz will sound.

    Anyone with a similar setup have the ICBM?

    As usual, my mind is wandering before this sucker gets here and I can listen and demo for myself.

    Thanks all.
     
  2. BruceD

    BruceD Screenwriter

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    Scott,

    Typical crossover advice goes something like this:

    A crossover point should be selected approximately one (1)octave above the lowest -3dB response for a main, center or surround speaker.

    The reason for this one octave "ramp" is that the speakers are still producing output below the crossover point and in order to get a smooth transition between speakers and sub you need to give them room to breathe (mix) between speaker and sub.

    For your speakers this means 100Hz may provide the best crossover performance (see below), although you should experiment with 90Hz and 80Hz on the ICBM to see how they sound. The ICBM should also allow you to try different crossovers for each speaker (L&R surrounds together).

    Frequency response +- 3 dbs is as follows:

    600S2: 52Hz - 20Khz (xover 100Hz105Hz)

    LCRS2: 58Hz - 20Khz (xover 100Hz120Hz)

    HLS610: 55Hz - 20Khz (xover 100Hz110Hz)

    ASW1000: 25HZ (xover 100Hz)

    The ICBM was designed for DVD-A and SACD bass management.

    Remember if you use the ICBM for DD or DTS bass management, you need to have all speakers equal distances from the listening position and all delay settings on all channels set to zero (0).

    Bruce
     
  3. Scott O'Keeffe

    Scott O'Keeffe Stunt Coordinator

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    thanks Bruce, exactly the type of feedback I wanted to hear. Someone who knows a lot more about xovers than me!
    [​IMG]
    thanks again.
    Scott
     
  4. John Kotches

    John Kotches Cinematographer

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    Bruce,

    Outlaw recommends a slightly different practice for determining crossover frequencies.

    Take your low end frequency response. Add 10Hz to this value. Go up to the next crossover frequency above this.

    In Scott's case, this would be:

    52Hz --> 80Hz Crossover point

    58Hz --> 80Hz Crossover point

    55Hz --> 80Hz Crossover point

    Subwoofer is irrelevant unless you're going to a sub-subwoofer.

    60Hz is cutting it close, 100Hz might cause localization issues.

    Try all of the above, and see which you are most satisfied with.

    Regards,
     
  5. BruceD

    BruceD Screenwriter

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    Good point John.

    Since I don't have an ICBM, I don't know what works best with it.

    In my own experience with in-room measured response for frequency and phase I have come to my own conclusions.

    I will say I don't like the bass management in many receivers/processors that use the 2nd order 12dB/octave crossovers with too much phase distortion. I would think with only a -12dB slope that it is even more important to give units a full octave to integrate. The assumption is that another -12dB will be provided by a "sealed" NOT "ported" main speaker. How many of us use "sealed" main speakers?

    Because of this, I prefer -24dB LR xovers with zero degrees of phase distortion provided by my electronic xovers instead of what is provided by many HT units.

    Yes 100Hz might cause localization issues, but 100Hz probably has a better chance of integrating smoothly while 80Hz may not give a smooth transition between mains and sub.

    Only actual experimentation will reveal what works best.

    BruceD
     
  6. John Kotches

    John Kotches Cinematographer

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    Bruce,

    Correctly implemented a digital domain crossover should be phase coherent.

    The ICBM is within 1 degree.

    Regards,
     

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