Blending the sub and fronts?

Discussion in 'Archived Threads 2001-2004' started by Tom Morgan, Jul 6, 2002.

  1. Tom Morgan

    Tom Morgan Stunt Coordinator

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    I have a Marantz SR-7200. I have a Polk PSW140 sub(10"185W) and Polk RT800i fronts. I have the sub hooked to the sub out of the 7200 ( all other speakers set to small). The sub out on the 7200 is filtered. The sub has its own adjustable filter. So there are two different low filters, one in the sub and one in the 7200( both active in current setup). Would I be better off running the front speaker cables to the sub and then to the fronts and set the fronts to large( then use the sub crossover to adjust)? Would it be better to use the front pre outs of the 7200 right to the sub line level inputs and set fronts to large(then use the sub crossover)? Would setting the fronts to small filter the front pre outs? This would also keep the sub working in Source Direct mode for stereo listening.
    Anybody with similar stuff experiment with any thing like this?
    How can I measure the response?
    TIA for any and all replys.
     
  2. Cees Alons

    Cees Alons Moderator
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    Tom,
    That would depend on your listening content. If that's audio exclusively, it could be a nice idea to "merge" your sub better with the fronts by using the same signal.
    But if you also have lot 5.1 material, like movies etc. ([​IMG] ), you would lose the LFE-channel that way. Don't worry about the blending, your receiver will do a fine job separating the frequencies. Just set the turn-over of your sub higher than the turnover of your receiver (if possible, at least 2x as high). That way you will get all low frequencies through your sub, those of fronts, center and the rear channels as well as the LFE.
    And if your receiver turn-over is lower than, say, 80-90Hz, you don't have to worry about the blending factor in the least. Play a little with the phase setting to see if you can get better results in that respect even.
    Cees
     
  3. Tom Morgan

    Tom Morgan Stunt Coordinator

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    If I set the receiver to "no" sub with the speaker level inputs on the sub being used or the front pre outs to the line level on the sub, won't the LFE channel be sent to the fronts/sub? I am assumeing/hopeing that by telling the receiver there is no sub I will still get the same LFE stuff, just routed to the fronts.
     
  4. Bill Kane

    Bill Kane Screenwriter

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    Using the rcvr's sub line-out and setting SWFR to NO with LARGE speakers you will get low bass at mains but no DD .1 LFE because that is always routed to the sub. That wud be fine for CD music, tho. Your fine Polk towers can go down to 35Hz.
    I am not addressing speaker-level connections, and I'm uncertain what your "front preouts" are.
    Here's some reading:
    LFE Channel
     
  5. John Garcia

    John Garcia Executive Producer

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    I have Paradigm Monitor 5s teamed with a 6200. Paradigm's site says the 5s are good to a -3dB of 35Hz. That does not mean they are efficient or effective all the way down to that point, and I set them to small, set the sub at it's highest x-over point, which for me is 150Hz, and let the receiver's x-over handle the blending. These receivers use a 100Hz x-over which will still roll off frequencies as low as 50Hz to your mains, and as high as 200Hz to your sub.

    Since my sub's highest cutoff is 150Hz, I am losing a bit from it between 150 and 200, but that is already rolled off quite a bit by the receiver's x-over anyway, and the mains are also covering completely to 100Hz.

    If you calibrate the speakers correctly, you can also set the mains to large and sub = yes, and things will still work fine. I sometimes do this for music, and you will still have the dedicated LFE channel available for movies. Without calibration, you might get some boominess.
     
  6. Tom Morgan

    Tom Morgan Stunt Coordinator

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    John and or anybody,
    Does the 6200 have pre outs? Have you ever tried them to the sub so that in Source Direct the sub would be active?
    I am considering trying that. A question would be if I set the receiver to "no" sub will the LFE be sent to the fronts and the front pre outs? If yes, I would then have all the bass info from a DVD, plus I could use the adjustable crossover on the sub.

    P.S. My next question would be if I set the center and rears to small, what would happen to the bass meant for those channels?
     
  7. Michael Lomker

    Michael Lomker Stunt Coordinator

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    If you have the rear and center set to "small" then the bass will go to your main front speakers (or to the sub if you have one enabled).

    I leave my center set to large because the center is mostly for speech (low bass isn't likely) and it sounds a bit better without the 100hz cut-off.
     
  8. Dustin B

    Dustin B Producer

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    Also remember that in most sub plate amps although the low pass filter is variable, the high pass on the speaker level inputs is usually fixed at around 120hz. Will be the same even if you run line level connections of your mains through the sub.

    With THX certified receivers the high pass is a 2nd order at 80hz while the low pass is a 4th order at 80hz. THX relies on a speaker to have a 2nd order roll off and a -3dB point of 80hz.

    It's tough to find out what the slopes are and where they start on non THX certified receivers. We do know Marantz uses a 100hz crossover point. But whether this is with 2nd, 3rd, 4th or mixed order slopes I have no idea.
     
  9. John Garcia

    John Garcia Executive Producer

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  10. Dustin B

    Dustin B Producer

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    I know my Onkyo is at 80hz and not THX. I emailed and asked for specifics, they wouldn't provide. Try Marantz and see if they aren't so tight lipped.
     

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