ICBM + a receiver-as-a-pre/pro...

Discussion in 'Archived Threads 2001-2004' started by Kevin C Brown, Aug 11, 2002.

  1. Kevin C Brown

    Kevin C Brown Producer

    Joined:
    Aug 3, 2000
    Messages:
    5,712
    Likes Received:
    0
    Trophy Points:
    0
    The Outlaw 950 is late. So I'm looking at alternatives.

    The Yamaha RX-V1300 has everything I want, accept for good bass management. (Have also looked at the Denon 3802, H/K 520, Onkyo 797...)

    So would the following work?

    Use the ICBM on the "pre out" outputs from the receiver before the power amps? The ICBM does support 6.1, I just saw from the literature (cool!).

    Then I'd set the receiver config for my speakers as all large, subwoofer yes. (So the receiver would still send the DD/DTS LFE signal to the sub, but the ICBM would route all crossed over bass to the sub too.)

    I think all that would work.

    Here's where I get confused.

    1) If I do properly set the distances/delays to all the speakers, how will the ICBM handle that? There will be phase differences around, right? (But I can separately adjust the phase between the mains and the sub anyway.)

    1a) One solution here might be to set the mains as large and everything else as small, so all the bass gets crossed over and time aligned to the mains, and then I send to the ICBM which better bass manages. But then I lose the ability to set different crossovers for each set of speakers. (Yamaha has fixed 90 Hz, but I really need to use 120 Hz for my center, but 60 or 80 for my mains.)

    2) The best way might be to set all those distances the same, all speakers as large, but then I lose "time coherency" within my system.

    Any help would be appreciated... Thanks!
     
  2. Kevin. W

    Kevin. W Screenwriter

    Joined:
    Oct 27, 1999
    Messages:
    1,534
    Likes Received:
    0
    Trophy Points:
    0
    Wait for the Outlaw unless its going to be a long time coming. You'll be wanting the pre/pro down the road if you get the receiver now.

    Kevin
     
  3. Kevin C Brown

    Kevin C Brown Producer

    Joined:
    Aug 3, 2000
    Messages:
    5,712
    Likes Received:
    0
    Trophy Points:
    0
    Kevin- I hear you, and that is a choice, but...

    My original timeframe from the spring was mid Sept. That was to make sure that a lot of the hardware and software bugs had been worked out. Now, I'm thinking I wouldn't move on it until 3 months after shipping resumes. And even then, how long will the waiting list be?

    So the Yamaha + ICBM could be a short term solution (of about 6 months), or if I like it, keep it until we see a < $2k pre/pro from Yamaha, Denon, Onkyo, H/K, or Pioneer. The successor to the H/K 520 might also be an option. Supposedly, the new 225 has Logic 7 for 5.1 sources.
     
  4. Kevin. W

    Kevin. W Screenwriter

    Joined:
    Oct 27, 1999
    Messages:
    1,534
    Likes Received:
    0
    Trophy Points:
    0
    What are you currently using right now? What is it about your setup that needs this sudden change? I get the feeling your having symptoms of upgraditis. Are the bugs with the Outlaw that serious?

    Keivn
     
  5. Chuck Kent

    Chuck Kent Supporting Actor

    Joined:
    May 29, 1999
    Messages:
    983
    Likes Received:
    0
    Trophy Points:
    0
    I have been running my Denon 3802 as a pre/pro since the day I bought it. And when it became available, I added an ICBM between the 3802 and my 5 channel amp. I have been very pleased and have consistant bass management for both movies and music (I also use a parametric eq. for my sub to help with the music blend.) All of my speakers are set on the Denon as large with the sub on. The ICBM is set with the fronts at 60Hz, the center and surrounds set at 100Hz.

    While the delay issue may be a problem on paper, I have not heard anything sounding amiss. My feelings are the same as the note in the ICBM manual. That is that most rooms have enough bass issues going on that any very minor delay problems are masked beyond our hearing.

    The only thing that does matter (when using an ICBM between a pre/pro and an amp) is the individual channel level relationships. IOW, you should send all channels to the ICBM at the same volume level. Then adjust the individual levels just before they are amplified (but after the ICBM.) This insures the redirected bass from each channel is the same volume.

    The easiest way to accomplish this is to use amps that allow the user to adjust the amp's input level. You use the amp's input level adjustments to matchup the individual speaker outputs.
     
  6. Lewis Besze

    Lewis Besze Producer

    Joined:
    Jul 28, 1999
    Messages:
    3,134
    Likes Received:
    0
    Trophy Points:
    0
    The delay issue is definitelly a concern.
    I tested this with some DVD-A's I have,and compared the DTS tracks to the MC tracks on those,and the properly delayed surrounds were[DTS] sounded more cohesive,then the uncorrected DVD-A's.I must say though that the difference between my surrounds and mains[distance wise] is 5ft[between me and the speakers],so if the difference is less then that you may observe less of a "dramatic" difference.
    Any how this is an issue with the 950 pre/pro's 6ch external input,as I have one,but personaly I woildn't use the ICBM[full time] unless all my speakers are at equidistance.
    BTW I would recomend the Denon over the Yamaha.
     
  7. Kevin C Brown

    Kevin C Brown Producer

    Joined:
    Aug 3, 2000
    Messages:
    5,712
    Likes Received:
    0
    Trophy Points:
    0
    Chuck- Hmmm... I have to think about the volume thing some more... If I adjust levels this way 1st:

    receiver -> amps -> speakers
    ............-> subwoofer

    And then just add the ICBM:

    receiver -> ICBM -> amps -> speakers
    ..........................-> subwoofer

    Wouldn't I be OK as long as no volume tricks are being played by the ICBM?

    (I *don't* have adjustable amps...)

    Lewis- I hear ya! Just that I had a Yamaha receiver-as-a-pre/pro before the Sony pre/pro I have now, so it's somewhat a case of "going for what I know."

    Some of it is upgradeitis, some of it is just being tired of waiting for Outlaw...
     
  8. Chuck Kent

    Chuck Kent Supporting Actor

    Joined:
    May 29, 1999
    Messages:
    983
    Likes Received:
    0
    Trophy Points:
    0
    Kevin: No, the difference is because the Denon performs it's Large/Small crossover functions before you make your channel level adjustments. The ICBM will go into the audio chain after the level adjustments.

    An example...if say, your surrounds need to be 3db lower than your mains. If you use the ICBM between the Denon and the amp and send the surround signals to the ICBM 3db lower than the other channels, the lowpassed signal sent on to the subwoofer is 3db lower for any surround information than it would be for any main channel lowpassed subwoofer signals.

    How much this might be audible or not would depend on how sensitive one is to these kinds of things. But I imagine that bass level differences would be easy to hear for many of us.
     
  9. Lewis Besze

    Lewis Besze Producer

    Joined:
    Jul 28, 1999
    Messages:
    3,134
    Likes Received:
    0
    Trophy Points:
    0
     
  10. Kevin C Brown

    Kevin C Brown Producer

    Joined:
    Aug 3, 2000
    Messages:
    5,712
    Likes Received:
    0
    Trophy Points:
    0
    I'm still not getting it. (And there was no mention of the "volume thing" in the ICBM manual even though they do have a section on placing it after the pre/pro, receiver before the amps.)
    Your 3 dB example: If I set all the volumes the same into the ICBM and adjust after, wouldn't that mean that now the bass info being sent from the surrounds to the sub is now 3 dB too loud compared to the mains?
    Don't I *want* the volume adjusted before crossing over?
    (Man, why am I having so much trouble thinking about this? [​IMG] )
    Lewis: if the 3803 was out right now, that'd be the one. I like how Denon does 5.1 DD/DTS sources for a 6.1 speaker setup. The Denon has 24/96 DACs, 1 coax input, 1 digital rec output; the Yamaha 24/192, 2 coax ins, and 2 digital outs. I actually just emailed Yamaha to see if their "DSP processing" does indeed support 5.1 sources on a 6.1 speaker system other than just "simple" EX & ES matrix decoding back there...
     
  11. Chuck Kent

    Chuck Kent Supporting Actor

    Joined:
    May 29, 1999
    Messages:
    983
    Likes Received:
    0
    Trophy Points:
    0
    Kevin: No, you still need to make the volume adjustment after the crossover. In order for the program to stay in balance (the way it was mixed and intended) all of the channels need to stay equal. When you change the level of one channel in relation to another, you are adjusting for the sensitivity differences of your speakers, not the surround program itself.

    Lewis: I don't know why that would be the case but it shouldn't be...
     
  12. Lewis Besze

    Lewis Besze Producer

    Joined:
    Jul 28, 1999
    Messages:
    3,134
    Likes Received:
    0
    Trophy Points:
    0
     
  13. Kevin C Brown

    Kevin C Brown Producer

    Joined:
    Aug 3, 2000
    Messages:
    5,712
    Likes Received:
    0
    Trophy Points:
    0
    Lewis- I'm looking for something similar to Outlaw's CES modes, or Rotel's xS modes. The Denon has "widescreen" mode: "all signal sources are played in 7.1-channel mode, including DPL and DD 5.1-channel sources." And "non mtrx" mode for the surround back channel for dd/dts sources for 6.1/7.1 setups: the info from the surrounds is simply "copied" to the rears. I assume if it's one rear, that it simply creates a mono signal from the L + R surrounds.

    Chuck- I get it. I kept thinking about the bass in relationship to the speaker it was formerly associated with, but it's really more to each channel. So they should be equal before crossing over. Hmmm... Now I have to look at the ICBM manual again, no channel output adjustment knobs, right?
     
  14. Chuck Kent

    Chuck Kent Supporting Actor

    Joined:
    May 29, 1999
    Messages:
    983
    Likes Received:
    0
    Trophy Points:
    0
    Kevin: Nope, separate level adjustments are MIA on the ICBM. It was one of the few criticisms Sound and Vision made about the unit. While I have been able to accomodate the "problem", adding individual channel level adjustment controls and a 2nd set of inputs would make the ICBM nearly perfect (IMO.)
     
  15. Doug_B

    Doug_B Screenwriter

    Joined:
    Feb 11, 2001
    Messages:
    1,081
    Likes Received:
    0
    Trophy Points:
    0
    Resurrecting this post, as I just ordered an ICBM to place between my pre/pro and amps and within the last day came across the volume issue on HTF.

    First, for the near term, I only plan on using the main and sub connections on the ICBM because 1) my main need is to use my sub for redbook CD and 2 channel SACD from multiple source players while using the players' analog outputs (not impressed with multi-ch with the SACD material I have so far) and 2) I don't have enough cables (yet) to do all the channels anyway. I am assuming I can disengage ICBM for DD/DTS material and just use my pre/pro for bass mgmt, at least while I'm only semi-connected, correct?

    Second, it's unclear to me how pronounced the volume issue can be. For just 2 channel music, there doesn't seem to be an issue, as I can adjust sub level with my sub amp, if it's even necessary. For multi-ch, I can understand that redirecting bass from my surrounds, which are set ~6.5 db higher than mains and even higher than that relative to my sub, can appear to present a problem. But I wonder whether this difference is mitigated due to 1) our lower hearing sensitivity to bass frequencies, and 2) the fact that the Avia test signals sent to the mains and surrounds (which I used to calibrate) contain a wide range of frequencies, and it's possible (although I have no clue) that if one was level matching using just bass frequencies, a different relative db level between speakers might result (hopefully less of a difference).

    Thoughts?

    Doug
     
  16. Chuck Kent

    Chuck Kent Supporting Actor

    Joined:
    May 29, 1999
    Messages:
    983
    Likes Received:
    0
    Trophy Points:
    0
    Doug: I agree that the amount that each of us may or may hear (re: channel to channel level problems) may differ. But for me, it's still more of a worry than the delay issue.

    It's (the channel level matching issue) apparently enough of a concern that Roger Dressler from Dolby pointed it out to some of us in a thread on the ICBM at the AVS forum a few months back...
     
  17. Kevin C Brown

    Kevin C Brown Producer

    Joined:
    Aug 3, 2000
    Messages:
    5,712
    Likes Received:
    0
    Trophy Points:
    0
    One of the things I have yet to do, is to go back and see what my levels are to try and judge whether the volume thing would be a big deal or not. (I currently have a DPL processor on the back 2 channels to get the rear center. Need to disconnect that and redo levels.)

    I think I am convinced that the delay issue isn't that big a deal (at the freqs involved), but the individual channel volume issue still has me thinking...
     
  18. Doug_B

    Doug_B Screenwriter

    Joined:
    Feb 11, 2001
    Messages:
    1,081
    Likes Received:
    0
    Trophy Points:
    0
    As I'm getting the ICBM delivered today, I guess I'll be experimenting somewhat in the next few days while I'm still taking some time off of work. I'll be fooloing around with simple 2 ch redbook and 2 ch SACD first. It would seem that since the two main channels are being driven by a different amp than my sub (Samson S1000 for the latter), that the resulting sub level (after being split by the ICBM) would be arbitrary relative to the main levels. I guess I would adjust S1000 level to my liking. Then I suppose I can fool around with pre/pro sub level using Avia calibration to get back to a calibrated level for DD/DTS sources again, so that the S1000 level can stay constant for all sources. May work, although I also have a Behringer Feedback Destroyer in the loop for which I've already set up from a max signal / clipping perspective using the pre/pro, so this would get screwed up (if more than a couple of db difference). Eventually, I guess I'd get into more volume issues once I set up the ICBM to handle multichannel music sources (I have felt no need to date for more bass mgmt flexibility than available via my pre/pro to handle DD/DTS sources). I would put the ICBM before the pre/pro if I only had one music source, but that's not the case, and I doubt I'll be there in the near future, even if I got a universal SACD/DVD-A player.

    Edit: Forgot that the ICBM has a sub out level control. Thus, I can adjust sub level for my two channel music from ICBM and counter that with pre/pro setting adjustment for DD/DTS, so S1000 need not be changed. I guess this will get more complicated with full 5.1 ICBM connectivity.


    Doug
     

Share This Page