Strange bass management situation figured out!

Discussion in 'Archived Threads 2001-2004' started by Philip Hamm, Jul 31, 2001.

  1. Philip Hamm

    Philip Hamm Lead Actor

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    Untill tonight I had assumed that my receiver did analog bass management on the 5.1 channel ins. After all, it's got settings for High Pass Filter and Low Pass Filter and the THX logo on them. I think I know what a HPF and LPF are, and turning them on should direct the bass to my sub, right? After all, I've been hearing big bass for years out of my system with the 5.1 ins, even with the Tarzan 5.0 DVD!
    Well, my new Technics DVD-A player has shown me the light. The old receiver works just like the newer ones, passing the 5.1 signal straight through unchanged to my speakers.
    My first hint was some strange bass problems on a select few DTS tracks. First the Steely Dan "Two Against Nature" DVD. Then the Paul McCartney "Live at the Cavern Club" DVD. Then most recently the Steely Dan DVD-A, in DTS mode. On all of these if I used DD I got big bass, but in DTS it sounded weak. The answer, my friends, is simple.
    All this time I have been operating under the assumption that my receiver was doing bass management, when in fact, my ED-901 DD decoder has been doing it all along. This confirmed by setting the speakers to large in the Technics and playing back the Tarzan DVD and A/Bing the two decoders. ED-901 - BOOM BOOM Technics - boom boom. What about that!
    All the DTS movies I've watched on LD and all the DTS CDs I've enjoyed have been mastered with the bass rolled into the LFE tracks. Why? Because most people who think their speakers can handle "large" are wrong, and DTS wants to make damn sure that their stuff sounds good on those systems. [​IMG] That's all I can think of. The DTS tracks that I listed above were mastered with the LFE on the mains unmodified. (side note - I now understand why the esteemed Robert George started his bass management thread following the original Jurassic Park DTS release.)
    So the good news is that my new DVD player will fix a problem that I've had with DTS discs, and would have with more and more discs as they're mastered more accurately.
    The very slight bad news is that with DTS tracks I'll be listening to my crossover points at 100kHz. DD will still be 80 thanks to the ED-901. I will A/B them to see if this small change makes any difference.
    But the bad news is that my system can't do proper bass management for DVD-Audio! Something I thought would not be a problem!!! Time to take it up with Panasonic I guess. [​IMG] I'm sure they won't fix it but it's worth asking about anyway.
    Now the real question is what the hell do the L.P.F. and H.P.F. switches do on my damn receiver for the 5.1 ins!??!? The book says the following:
    quote: High Pass Filter (H.P.F.) / Low Pass Filter (L.P.F.)
    This function provides an active crossover between the front speakers and the subwoofer speaker. The high pass filter removes the low bass from sounds sent to the front speakers. The low pass filter removes any mid-range and high frequency sounds from the signals sent to the subwoofer output.[/quote]Not really sure what the function of these filters is. I'd love an explanation. I don't understand!!! [​IMG]
    I, Philip Hamm, am a bass management idiot. [​IMG]
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    Philip Hamm
    AIM: PhilBiker
    [Edited last by Philip Hamm on July 31, 2001 at 11:00 PM]
     
  2. Alex Shk

    Alex Shk Stunt Coordinator

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    Is this related????
    I have my speakers set to large - never had a problem with this setting, until...
    Listening to Wings "Venus and Mars" DTS CD (a truly dreadful old quad mix - btw), I noticed that the 4.0 sound was NOT flagged for a subwoofer. It was thin and "trebly". Turning my receiver (Yamaha 5460) to "effect off" mode (that folds the dts signal to 2 channel stereo), the sub came alive, and the disc sounds much better.
    It does seem strange that I would have to modify my speaker setting just for this disc, though.
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  3. Vince Maskeeper

    Vince Maskeeper Producer

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  4. Lewis Besze

    Lewis Besze Producer

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  5. Philip Hamm

    Philip Hamm Lead Actor

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    Alex,
    Turn your speakers to small, go back to DTS mode and see what happens. I guarantee all the bass you were missing will be there. I think that V&M is a wonderful old quad mix, and I can't wait to hear it with proper bass.
    quote: I think it's part of the reciver's THX post processing[4.1 in this case].THX was big on from the get go,as to where the bass should come from.Most THX speakers were the Sat/Sub configuration type,they also advocated the 80hz point for both the LP and HP filters.I guess it's only works on the recivers internal DPL with the THX movie? mode engaged.That's my guess.[/quote]If that were the case, why would I even have these options in the external decoder mode? (I can't for the life of me figure out what the hell they're for there).
    Here's the way I think it works in every mode other than external decoder:
    Turn "Sub" on and the FULL RANGE SIGNAL from the L/R outputs is sent to the sub. The 919 hardcodes the rear speakers to "small", so this includes those speakers also. If you have a surround mode selected and a "small" center (that's the only speaker that is selectable for size) then that ghes there. - This is the way the sub out on my Harman Kardon HK3270 stereo receiver works. -
    The H.P.F. and L.P.F. are completely independant of one another. The H.P.F. operates only on the mains and the L.P.F. operates only on the sub. This balances the sound perfectly at 80Hz for all surround modes even by-pass (the filters are analog).
    The 919 was made when the THX program was new. It was also the first 5.1 input receiver made. I'm dealing with some old school stuff here!!!
    So the question remains why have the LPF and HPF int he external decoder mode?
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    Philip Hamm
    AIM: PhilBiker
    [Edited last by Philip Hamm on August 01, 2001 at 06:51 AM]
     
  6. Philip Hamm

    Philip Hamm Lead Actor

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    By the way Vince, I suspect the problem with the Beastie Boys Disc's 5.1 mix is too much bass in the mains, not the LFE track. With my ED-901 decoding it, switching the "LFE -10" does almost nothing.
    Actually that disc has by far the worst 5.1 music mix I have ever experienced in my life. It is unlistenable.
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    Philip Hamm
    AIM: PhilBiker
     
  7. Philip Hamm

    Philip Hamm Lead Actor

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    quote: The 919 was made when the THX program was new. It was also the first 5.1 input receiver made. I'm dealing with some old school stuff here!!!
    So the question remains why have the LPF and HPF int he external decoder mode?[/quote]I think I figured this out on my own. The ED901 was specifically made for the 919 and 828 receivers. I highly suspect that the ED-901 does the same thing with the bass from the mains, center, and surrounds that the 919 does. It sends the full range signal to both the mains and the sub output. Ahhhh.... complicated...... So I'll have to turn the HPF and LPF "on" to get proper sound from my DD LaserDiscs but "off" for DD DVD from the Technics decoder.
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    Philip Hamm
    AIM: PhilBiker
    [Edited last by Philip Hamm on August 01, 2001 at 07:14 AM]
     

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