Outlaw ICBM question: Recombine/LFE weirdness??

Discussion in 'Archived Threads 2001-2004' started by Mike Sloan, Mar 3, 2003.

  1. Mike Sloan

    Mike Sloan Second Unit

    Joined:
    May 18, 2002
    Messages:
    456
    Likes Received:
    0
    Trophy Points:
    0
    I understand that the recombine switch returns the bass directed to the sub back to the Front L/R speakers. With the recombine "on" I also notice that the LFE is also re-directed to the Front L/R speakers. Now here is where it gets weird: With the Spyro Gyro SACD and a few others it seems that the LFE contains "full-range" information and enabling the recombine switch, not only increases the bass, but increases the level of vocals, trumpets, and higher frequency info that normally is not associated with the LFE. Could I be picking up height channel info or non standard LFE stuff? It's happened a lot with Telarc label SACD's! Please explain.

    Thanks
    Mike Sloan
     
  2. BeatCrazy

    BeatCrazy Stunt Coordinator

    Joined:
    Mar 7, 2002
    Messages:
    129
    Likes Received:
    0
    Trophy Points:
    0
    The "recombine" switch only sends low frequency info from the main speakers at frequencies below the crossover settings that you put on the main speakers. So, there should be no reason to get vocals, etc. out of your sub.

    If the LFE channel on the SACD really does contain vocal or "height" information, you should set your SACD player to 5 large speakers + Sub and you should get rid of this problem.
     
  3. Mike Sloan

    Mike Sloan Second Unit

    Joined:
    May 18, 2002
    Messages:
    456
    Likes Received:
    0
    Trophy Points:
    0
     
  4. BeatCrazy

    BeatCrazy Stunt Coordinator

    Joined:
    Mar 7, 2002
    Messages:
    129
    Likes Received:
    0
    Trophy Points:
    0
    Mike,

    You need to do what I suggested in the 2nd part of my post. Set your SACD player to 5 Large speakers + Sub and it should disregard the LFE channel and let your main speakers run full range. You'll have to test what the LFE gets in this situation. This setting (on Sony players) is different that the setting of "Multichannel Direct" which would leave you with the situation you're describing.
     
  5. Rich Malloy

    Rich Malloy Producer

    Joined:
    Apr 9, 2000
    Messages:
    3,998
    Likes Received:
    0
    Trophy Points:
    0
    This is interesting... I've heard about Telarc's unusual usage of the "sixth channel", but I've never thought about the problems this will cause most systems (how many of us have a "height envelope channel" anyway?).

    But I've got another possible workaround. I haven't thought this through entirely, but the ICBM also has an input for a center-rear signal. What would happen if you physically changed the cable from the LFE input to this input, and then did the "bass recombine" thing? Would it then redirect the bass/lfe to your mains, but "throw away" all the signal above the crossover setting for your "center rear" channel? Again, I haven't thought this through, but it might give you some added flexibility.

    (And Telarc doesn't recommend anything in particular? Do they simply presume that we all have "height envelope" speakers, and we're out of luck if we don't?)
     
  6. Mike Sloan

    Mike Sloan Second Unit

    Joined:
    May 18, 2002
    Messages:
    456
    Likes Received:
    0
    Trophy Points:
    0
    Rich, I think you are on to something! I think it would through away the full range stuff and send the "crossed-over" info back to the mains and to the sub....I need to think about this because it warps my brain! I did a search on "non-standard LFE" and Telark and Chesky popped up all over! I think it is crazy to master SACD/DVD-A with height channel info....because it screws up everything us "hometheater" guys have set up. Chesky seems to have backed away from the LFE and center rear philosophy and have introduced (2) center height channels....this reaks havok on the conventional setup....since 99% of the multi-channel SACD/DVD-A's are conventional in their use of the LFE. The way I have fixed it now is just to not use the recombine feature of the ICBM (which I probably don't need...double bass thing) and engage the crossover on the sub in it's full up position.....I may try what you suggested...VERY INTERESTING! If you go to the Chesky Website...Mr. Chesky talks about the use of the LFE/Center rear for full range height info...sort of arrogant to through a monkey wrench into this arena...where normal people are struggling just to stay up with the technology.
     
  7. Rich Malloy

    Rich Malloy Producer

    Joined:
    Apr 9, 2000
    Messages:
    3,998
    Likes Received:
    0
    Trophy Points:
    0
    You're absolutely correct, Mike, but I can't quite fault Telarc for their approach (though I do believe there should be a recommended "work-around" for those with conventional home theater setups). They want to provide the very best music reproduction possible, and I've heard (but not actually heard) that their approach to multichannel creates the most realistic soundstage of any.

    Let us know how it works out!
     
  8. Mike Sloan

    Mike Sloan Second Unit

    Joined:
    May 18, 2002
    Messages:
    456
    Likes Received:
    0
    Trophy Points:
    0
    Actually talked to someone at Telark and they confirmed that it is becoming popular for engineers mixing multi-channel music to include full range info in the LFE. He also said that to avoid confusing the average consumer, there will be no instructions provided in the disc’s liner notes on how this combination track is to be employed, only a reference to the record label’s Web site where the curious and adventurous can find setup details on how to optimize their surround systems and include the height channel.

    So for us ICBM user, this means splitting the subwoofer out from the ICBM and running one side to the subwoofer (as usual) and then running the other side to the input for the center-rear signal on the ICBM. You would then run the rear center output from the ICBM to an outboard amp and on to your height channel.....NO THANKS! And what if Chesky decides to redirect the Center and use it for a height channel.....man I need a Valium! Thank god the ICBM does an excellent job of bass management....because the poor sap who only uses the BM in the DVD-A player is left out in the cold... According to Telark...When they utilize the LFE for other than Low Info...the bass information for the music is mostly mixed to the front L/R speakers. If one was to set their Front speakers to Large and everything else small..no bass would go to the sub..nada! Another problem of using the LFE track as a height channel is that, in most cases, it will simply be ignored and routed to the system’s subwoofer by default. No damage will result from this signal misdirection, but the subwoofer may not be giving the optimum bass response needed to fill-out the bottom end of the typical satellite surround system. The surround music playback may sound thinner than the movie soundtracks played on the same system. The consumer will be less than satisfied with the audio quality, but won’t know why. Furthermore, since the LFE is left "un-touched" (no BM on LFE) the sub will easily be localized and produce frequencies that are full range..unless you engage the crossover on the sub.

    Maybe with persuasion and experimentation I will come to appreciate this...but for now I am skeptical....can you tell? [​IMG] [​IMG]
     
  9. Mike Sloan

    Mike Sloan Second Unit

    Joined:
    May 18, 2002
    Messages:
    456
    Likes Received:
    0
    Trophy Points:
    0
    In my "RANT" above I forgot to get back to the original topic......That is why the ICBM user will hear an increase in "full range" information (as well as bass) from the Front L/R speakers when the Recombine is engaged. It is not only returning the "crossed over bass" back to the mains....but also the "non-standard" full range information added to the LFE for the height channel.....I'll go away now...at-least I determined nothing is wrong with my ICBM....now off to the store to buy more interconnects, more speakers, and another amp...sombody shoot me!
     
  10. BeatCrazy

    BeatCrazy Stunt Coordinator

    Joined:
    Mar 7, 2002
    Messages:
    129
    Likes Received:
    0
    Trophy Points:
    0
    Mike,

    Did you ever try the setting I suggested to your SACD player to eliminate the "height" channel completely before it even got to your ICBM?

    "It is not only returning the "crossed over bass" back to the mains....but also the "non-standard" full range information added to the LFE for the height channel...."

    This is not really what happens. With the recombine switch on, the ICBM is not returning any bass to your fronts, only sending them the original front L/R info untouched.
     
  11. Rich Malloy

    Rich Malloy Producer

    Joined:
    Apr 9, 2000
    Messages:
    3,998
    Likes Received:
    0
    Trophy Points:
    0
     
  12. Chriss M

    Chriss M Second Unit

    Joined:
    Dec 14, 2001
    Messages:
    320
    Likes Received:
    0
    Trophy Points:
    0
    this is one of the reasons why i listen to 2-channel SACD [​IMG]
     
  13. BeatCrazy

    BeatCrazy Stunt Coordinator

    Joined:
    Mar 7, 2002
    Messages:
    129
    Likes Received:
    0
    Trophy Points:
    0
     
  14. Chriss M

    Chriss M Second Unit

    Joined:
    Dec 14, 2001
    Messages:
    320
    Likes Received:
    0
    Trophy Points:
    0
     
  15. Rich Malloy

    Rich Malloy Producer

    Joined:
    Apr 9, 2000
    Messages:
    3,998
    Likes Received:
    0
    Trophy Points:
    0
    Mark, I know you mean well, but you're just flat-out wrong on all counts.

    Go to pg. 14 of your ICBM owner's manuel to learn what the recombine switch does (it will do what you say, among other things, but it's primarily intended to redirect bass to the front mains in systems running without a subwoofer).

    And as for the "5 large + sub" option, not only will this not solve Mike's "problem" (which isn't a problem, after all), but engaging it will degrade the quality of the signal.

    Again, I know you mean well... but your information is incorrect.
     
  16. Rich Malloy

    Rich Malloy Producer

    Joined:
    Apr 9, 2000
    Messages:
    3,998
    Likes Received:
    0
    Trophy Points:
    0
    Moreover, if one uses an ICBM for bass management (in any configuration) while also using the onboard bass management of the SACD player ("5 large + sub" or any other configuration), then one's setup is completely screwed.
     
  17. Mike Sloan

    Mike Sloan Second Unit

    Joined:
    May 18, 2002
    Messages:
    456
    Likes Received:
    0
    Trophy Points:
    0
    Sam Scamardo,
    Sorry for not responding in a timely fashion...I have been in Tucson helping my Brother-in-law with his new HT system.


     
  18. Rich Malloy

    Rich Malloy Producer

    Joined:
    Apr 9, 2000
    Messages:
    3,998
    Likes Received:
    0
    Trophy Points:
    0
    Mike, remember that the primary purpose of the recombine switch is for systems without a separate subwoofer. If you have no way of redirecting the LFE signal (in addition to the bass below the crossover points of your center and rear speakers), then it's simply lost. That's why it's crucial that the LFE be sent to your mains when the recombine switch is engaged.

    Did you read closely the stuff I quoted from the Telarc site? I don't believe this is a problem at all! The so-called "LFE channel" is no longer being used as a discrete bass-carrying channel. Rather, it's being utilized as an optional height envelope channel. Optional.

    Just as they should, Telarc sends a full-range signal to all channels. This is the proper, purist approach. Ideally, we'd all have full-range speakers in all channels, but in truth we have a variety of different sized speakers from system to system. It's true that some of us have tiny rear speakers, but of course Telarc certainly shouldn't mix their recordings for the home-theater-in-a-box crowd! Rather, they should provide the "perfect" mix, and then we can bass manage that signal to fit our systems.

    So, by ignoring the height-envelope channel (which is referred to as "LFE" merely as convention, not by Telarc's actual use of it), you are not losing any low-bass info. All the low-bass information is being sent to your speakers already in the form of full-range signals.

    Which, of course, begs this question: why would any studio utilize an LFE channel for music? Wouldn't this always be a pre-fab compromise for the "home theater in a box" crowd, and an irreversible corruption of the signal for the audiophile community (many of which have large full-range speakers and do not include subwoofers in their system at all)?

     
  19. John Kotches

    John Kotches Cinematographer

    Joined:
    Mar 14, 2000
    Messages:
    2,635
    Likes Received:
    0
    Trophy Points:
    0
    On the use of 6 channels....

    Telarc does in fact use the ".1" channel as a 6th "full range" channel on some channels.

    It is intended to use an LP/HP combo, with the Low Pass going to the subwoofer, and the High Pass going to the height channel. I think the crossover points are asymmetric (I'm not looking at any documentation) with the subwoofer getting 120Hz and below and the height channel getting 180Hz and above.

    Telarc uses a pair of Magnepans at ceiling level on their sides. The speakers are wired in series, so they get a fairly diffuse presentation, with the dipolars radiating above the listening station.

    Chesky does have a 6.0 configuration, with height channels. I wrote about this in our DVD-Audio article at Secrets (click here) in late 2001.

    MDG and Tacet are doing 6.0 as well.

    Regards,
     
  20. BeatCrazy

    BeatCrazy Stunt Coordinator

    Joined:
    Mar 7, 2002
    Messages:
    129
    Likes Received:
    0
    Trophy Points:
    0
     

Share This Page