Marantz SR 8000 crossover, source direct and pre-outs behaviour?

Discussion in 'AV Receivers' started by Chris PC, Nov 28, 2005.

  1. Chris PC

    Chris PC Producer

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    I have realized the behaviour of my receiver is different than I once thought. After going from an SR 6200 to an SR 7000, then an SR 8000, and along the way, testing an SR 6400 and SR 7400, I have been using it set to FRONT = LARGE and had the subwoofer connected to the front left and right pre-outs. I can't remember what I had the SUBWOOFER setting to, YES or NO, but it doesn't matter, since I watch movies in Source Direct. In Source Direct, regardless of the SUBWOOFER setting of YES or NO, the LFE goes to the subwoofer pre-out ONLY and not to the FRONT speakers and/or front pre-outs. I noticed that the SR 6400 and 7400 has SUBWOOFER settings of YES, NO and BOTH, but the SR 8000 does not have that. Anyhow...

    Here is my question:

    I have reverted back to FRONT = LARGE and SUBWOOFER = YES and I'm running the subwoofer off of the subwoofer pre-out. In Source Direct or normal, I get the LFE out the subwoofer each time.

    1) Am I still getting some LFE out the front speakers with the FRONT = LARGE and SUB = YES when not in Source Direct?

    2) What will happen to my bass and LFE when listening to non-DD DVD's? Will stereo and surround dvd's still allow bass out the Subwoofer output in Source Direct?

    In Source Direct, the receiver is supposed to simply pass the discrete information out the corresponding channels without crossovers etc. It seems obvious when the source is DD 5.1. I hear the fronts, the centre, the subwoofer LFE and the surrounds just fine in Source Direct. Just wondering how it works when I'm in Source Direct using a non-DD 5.1 soundtrack. I'll do some testing to see if I can figure anything out myself. I'm just wondering if anyone else has experience with this?

    My main question is whether I must dis-engage Source Direct in order to hear proper bass sound effects when not in DD 5.1.

    thanx

    [​IMG]

    P.S. Also, if I use SOURCE DIRECT or SUB = YES and there is a full LFE, that means the LFE is going only to the subwoofer, so should I leave my subwoofer crossover to 50hz as I've had it so far, or up it to 100 hz? I could remove the crossover in my setup but that would result in having no subwoofer volume control on the sub, making it next to impossible to calibrate the subwoofer and shakers separately. I'm not sure whether the subwoofer pre-out uses a 100 hz low pass crossover. I know the other channels use a 100 hz high pass when set to small, but I have never been able to figure out if the subwoofer uses a 100 hz low pass. Perhaps I should do some testing.
     
  2. John Garcia

    John Garcia Executive Producer

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    With mains large and sub yes, you should always get the LFE channel out of the sub. Only if you say sub no will the LFE be directed to the mains. With material that has no LFE, the sub will not be used for the mains, but should be used for any other speakers that are set to small.

    I don't know what speakers you are running these days, but I can't think of many that would not benefit from being set to small (though without an adjustable x-over that may not be ideal).
     
  3. Chris PC

    Chris PC Producer

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    My front speakers are PSB 6T towers and are rated to 32 hz -3 dB. In room, I would imagine the response is around 30 hz ish, maybe a few hz lower.

    I agree that with SUB = NO the LFE is directed to the front, except of course in Source Direct where all is large.

    Thanx for the info. I don't understand this part:


    Are you talking about the re-directed bass from the speakers set to SMALL? That I understand, but I don't run any speakers SMALL. Maybe I will after some experiments, but lets stick with the LARGE/SOURCE DIRECT case.

    Simplifying with all LARGE/SOURCE DIRECT, what determines where low bass sound and music comes from? Does this mean that only LFE comes from the subwoofer and nothing else? Is there ever a time when low bass music or other low bass sound effects comes from the subwoofer? Are there dvd's where low frequency sound effects aren't all in the LFE? Is it specific to the DVD? Will low bass music in a movie come out the subwoofer? See what I'm getting at?
     
  4. John Garcia

    John Garcia Executive Producer

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    Only hires music and DD/DTS streams have a .1 aspect to the signal. For CDs in stereo - there is no LFE, so the sub will get no signal, which means if you have your speakers set to large, even with sub=yes, it will get no signal. I don't think the 8000 had the "both" option for bass (which will send low bass, not LFE to the mains AND sub), because IIRC none of the others did.

    Bass and LFE are not the same thing. LFE is a discrete track that is sent to your sub; bass is whatever low content is present in any given channel that is not LFE. Bass redirection is determined by the x-over - based on the slope of the x-over, the bass is slowly "removed" from the speakers set to small, below the x-over point and sent to the sub.

    Source direct removes the x-over, setting all speakers to large and sending only LFE to the sub when it is present. Music in a movie is still part of the 5.1 track, so you will hear anything that is on the LFE channel, which it may or may not be.
     
  5. Chris PC

    Chris PC Producer

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    Right. I remember wanting to listen to the subwoofer with music when I first started on this crusade a few years ago. I may experiment with that again later, perhaps with a different crossover or something, but ultimately, I'd need a switch I think, to switch between sending the subwoofer the signal from the subwoofer output, or the left and right pre-outs. I'll leave that for now.

    So low bass in the music and sound effects in movies goes where? Just to the front? Not to the subwoofer? Hmmmm...interesting. So you are saying that with the front speakers set to large, they get all the bass and no bass other than LFE reaches the subwoofer?

    thanx

    [​IMG]
     
  6. John Garcia

    John Garcia Executive Producer

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    In your case, if you are saying all of your speakers are set to large, then yes, all the sub is getting is LFE for movies. In the case where someone had the mains set to large but the center and surrounds set to small, the bass from those channels would be sent to the sub. Low bass for each channel is sent to that channel for all speakers set to large, regardless of music or sound effects. AFAIK, the LFE channel can be designed to support the sound from any channel, including surround.

    Music within a movie is sent wherever the engineer decided it would be sent, which means the bass may show up on the LFE channel, though I'd expect in most cases it is not - background music for example, probably won't have it's bass show up on the LFE channel.

    We talked about SD before I think. I use SD essentially to turn the sub off for music. For most stuff, I have all my speakers set to small, but for late night or just times when I don't want the extension of the sub, I put it in SD which sets the mains to large. For CDs, there is no LFE, so the sub is on, but it gets no signal with my mains set to large.
     
  7. Chris PC

    Chris PC Producer

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    I guess I'm being too critical of the sound quality of Source Direct vs non-Source Direct.

    In non DD soundtracks, that is where it gets fuzzy for me. I guess I'll sit back with the DVE disc and experiment. With movies that have music with very low bass content, you would think it would show up in the subwoofer output, but I guess discrete vs dolby surround/stereo may be different.
     
  8. John Garcia

    John Garcia Executive Producer

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    For music, I use my PM7200 and no sub [​IMG] The funny part is, it has a Source Direct button too...just to disable the tone controls.
     
  9. Chris PC

    Chris PC Producer

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    My biggest frustration is the auto-off feature of my subwoofer. The subwoofer is always turning itself off. I guess I have to turn up the receiver output some more, and then turn down my subwoofer volume control, but I don't want to overload the subwoofer input. I am sure that can cause distortion.
     
  10. John Garcia

    John Garcia Executive Producer

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    Does it have a dual input? This can usually be solved by using a Y splitter to both inputs, which will give you additional input voltage at the sub.
     
  11. Chris PC

    Chris PC Producer

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    It does. I cannot see how that will increase voltage. I may give it a try though.
     
  12. Doug Otte

    Doug Otte Supporting Actor

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    Hi, John & Chris. I hope I don't muddy the waters further, but thought I'd try to clarify some points based upon my experience.

    If your speakers are set to large, the bass mix/both setting doesn't do anything. Nothing will be sent to the sub for any source except something that has data in the .1 channel (e.g. DD5.1 or DTS5.1). Any 2 channel source (CDs or TV broadcast) will only be sent to the L & R mains.

    If you set any of your speakers to small, then for any source, some low bass (depending on where you set the crossover) will be sent to the sub, even if you have data w/ a .1 channel. I use a 7400 and have towers for mains (KEF Q11). I set them to large but my center to small, so I get some bass in the sub for 2-channel TV broadcasts and DD2.0 movies. I don't remember if I have the bass set to mix or both, and I didn't play with it so I don't know how audible the difference is between the two. I prefer my music without the sub, so I use the 7.1 inputs and therefore don't worry about the Direct setting when listening to CDs.

    My sub (JBL PB10) has auto shutoff too, but it only shuts off if no signal is received for 3 minutes. And, it immediately turns on again as soon as it receives a signal. Chris, are you saying yours shuts off in the middle of receiving signal? If so, there must be a flaw. I've always used a splitter to send signal to both sub inputs, because I found the output with just one was too low.

    Cheers,
    Doug
     
  13. Chris PC

    Chris PC Producer

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    No, it doesn't shut off in the middle of receiving a signal. I am just suspicious that there is some low signal that is being missed when the subwoofer goes to sleep, and that it doesn't wake up until the lfe is loud enough to "wake" the subwoofer. Maybe I'm just bothered by seeing the light go from red to green while watching a movie. Annoying. I will up the level and use a Y-cable.

    thanx folks,

    [​IMG]
     

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