best 7.1 dsp, THX ultra 2, logic7, denon widescreen

Discussion in 'AV Receivers' started by David Proud, Nov 11, 2003.

  1. David Proud

    David Proud Stunt Coordinator

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    I am looking for opinions to help me decide on my theaters setup. I am building a theater with two rows. The first row will have the side surrounds to its side. however the back row will have the side surrounds in front of it. So I am adding to rear surrounds behind the back row on the rear wall to improve envelopment for listeners in that back row. What 7.1 dsp will give all listeners the best effect. I currently have a Denon-AVR4800 and will upgrade if needed.

    Ultra2 Cinema mode, Logic7, Denon Widescreen 7.1 Mode?
     
  2. ChrisLazarko

    ChrisLazarko Supporting Actor

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    Well HK offers Logic7, it's HK's unique feature. The only other closest thing with 7 channels is DPLIIx which won't be available in the US for another month or so I believe still.

    Check out the HK AVR-7200. It's Harman/Kardon's flagship reciever, has 100W for all 7 channels and plenty of features that will make you wonder how they could offer it for the price. Check it out, it's a great reciever and the price is just unbeatable until you get to seperates I personally think.
     
  3. David Proud

    David Proud Stunt Coordinator

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    I have been told the Denon Widescreen 7.1 DSP does basically the same things as DP EXII.

    Now I understand the merits of HKs logic7 but bear in mind I am working with much better amps than the HK flagship is offering. If I where to upgrade to logic7 it would have to be a) using a lexicon processor with 7 channel amp or my existing denon AVR-4800 or using a HK reciever ans a processor and use an outlaw 7 channel amplifier.

    Now from what I understand ultra2 cinema mode will produce stereo rear effects from 5.1 sources. The Denon AVR-4802 reciever features ultra2 cinema modes and music modes.

    So has anyone compared Ultra2 mode to , Denons widescreen mode and lexicons logic7?

    Remember my goal is to provide excellent surround sound for both rows of seating if I didn't have the 2nd row I would just stick with 5.1
     
  4. Kevin C Brown

    Kevin C Brown Producer

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    Here's my impressions:

    1) All of H/K's Logic 7 implementations only work with 2 channel sources. The 8000 receiver was the only one that worked with 2.0 and 5.1 sources to "expand" them to 7.1.

    2) Denon's "widescreen" mode only duplicates left surround to left rear, and right surround to right rear. No DSP processing to create the rear channels. The effect isn't bad, but it's not like DPL IIx or Logic 7.

    Lexicon's processors offer the best version of Logic 7, because you get a whole bunch of parameters to adjust to customize for your room, tastes, and speakers. The version that shipped with the 8000 was a lot more limited in terms of adjustments.

    I have THX Ultra2 and Logic 7 on the MC-8. To be honest, I use Logic 7 almost all the time. Never even felt a need to try Ultra2. But Ultra2 only does rudimentary de-correlation to create the left and right rears out of the matrix derived mono rear channel. DPL IIx should be "closer" to Logic 7 in that it does more intelligent "steering" to create the content for the left and right rears.

    Those are my impressions, anyway, and I'm sticking with them! [​IMG] Hopefully some more experts show up and tell us more.
     
  5. David Proud

    David Proud Stunt Coordinator

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    interesting. So DPIIx mode will not neccsarly be better at sterring surround information than the logic7 steering found in the lexicon processors? Is there a lexicon processor that can be had used for under 1500$ that you recommend?
     
  6. Ted Pugh

    Ted Pugh Stunt Coordinator

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    David,

    You can find a used Lexicon MC1 with version 4 software for around the $1500 price. This will give you the newest software as well as Logic 7 processing. Look at audiogon they usually have a few for sale.

    Ted
     
  7. David Proud

    David Proud Stunt Coordinator

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    Denon Widescreen Mode?

    From everything I have read it sounds like Denon 7.1 Widescreen DSP takes 5.1 and upconverts it to 7.1.

    This mode does it a little differently than DIIx or logic7.

    For my situation this mode acutally might sound better than DIIx. Consider the following.

    My first row of seating will be 12ft from the front screen.
    My side surrounds will be 13ft from the front screen.
    My third row of seating will be 16ft from the front screen.
    The two rears will be at 20ft on the back wall from the front screen.

    The reason I say it might sound better is.

    Row1 will get good imaging to its sides and behind it without any back surround speakers at all.

    Reason I need 7.1 configuration is for Row2.
    Just like the reason they put back surrounds in theaters for the rear rows to get wrap around sound and effects.

    Solution: Denon Widescreen 7.1 Mode

    Row2 with no rear speakers would loose wrap around effects and not get fly overs, etc and rear directional stuff. Denon Widescreen mode esseentilally copies stereo information from the two sides and places them in the back surrounds behind my back row giving the backrow the same effects the front row gets from the two side surrounds.

    When direction goes left to right in the side surrounds now the rear row would hear things moving left to right since the back surrounds copy the same stereo information from the side surrounds.

    WHY WOULDN"T DPIIx be ideal in my enviroment?


    If DPIIx steers left side surround action to the back rear speakers as it continues to move to the right side surround it could essentially collapse the rear image for the front row who does not need the back surrounds.

    Since my goal is to reproduce the rear imaging and rear directional activity one can get from using only two side surrounds seating on axis with the sides at the ITU 110 location the widescreen mode seems more ideal.

    Again, the only reason we are adding the back surrounds is for the rear row and off axis listeners.


    What are the downfalls to Denons Widescreen DSP?

    I am curious how the get by with phase cancelation issues, etc since there mode simply copies side surround activity to the two back surrounds.


    With that said I am seriously considering a lexicon MC1 but could save 1500 by going with the Denon widescreen mode for now.

    What do you guys think
     
  8. Shawn Fogg

    Shawn Fogg Stunt Coordinator

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    "The 8000 receiver was the only one that worked with 2.0 and 5.1 sources to "expand" them to 7.1."

    And it is worth noting that the 8000 actually downmixed a 5.1 source into two channels (discarding the LFE channel completely) then applied L7 to the resulting 2 channel mix to bring it back out to 7.1 channels after bass management. The 8000s downmix was a standard Dolby Surround downmix (not a L7 downmix) so it really wouldn't be much different then using the downmix of a DVD player and letting any of the H/K receivers run L7 on top of that.

    Shawn
     
  9. John S

    John S Producer

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    David, I have the Denon 4802, and use widescreen almost exclusively for my surround mode. It is excellent, I don't believe it is just a re-direct of other channels. I load up 9 JBL S38's on it, and man is it impressive, nearly always the best surround mode. Just run every mode A+B on the setup. The setup will fill an enormous room.
     
  10. David Proud

    David Proud Stunt Coordinator

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    so how do you have it configured?

    4 side surrounds and 2 bakc surrounds?

    Is the Denon Widescreen mode suspectiable to comb filtering and phase cancelation?
     
  11. John S

    John S Producer

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    Yes, two back surrounds, 4 side surrounds, I actually run the other two in parallel on top of my RP TV as my center (as s38's and s38II's were only sold in pairs) so I actually use 10 speakers + the sub.

    My room is 30'long by 15'wide by 10" high. How would I detect comb filtering on my multi-track surround, I am not even sure what it is to tell you the truth? I don't detect any phase cancellation going on, really seems strong throughout the spectrum, on both music and HT. The mirror image nature of s38's may help some with phase cancellation as well I suppose.
     
  12. Kevin C Brown

    Kevin C Brown Producer

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    John and David- Yes, Denon's "Widescreen" mode is a simple duplication of the surround channels to the rears. But you have to go through the manual with a fine tooth comb to find exactly where they explain it. No DSP. Just simple channel duplication.

    David- And actually, Widescreen mode might in fact be the best for what you're trying to do with multiple rows filled with lots of people.

    But ... I don't know about the MC-1/DC-2, but on the MC-8, if I have my system configured as a 7.1 speaker setup, and then run straight DD or DTS, it does exactly the same thing: copies the surrounds to the rears. So if you did spring for one of the Lexicons, it may actually allow you to compare the two modes. *And*, give you flexibility in terms of perhaps using one effect for when you have a lot of people over, but Logic 7 for when you have fewer people but might prefer the better steering of Logic 7.

    Nothing I've read so far leads me to believe that DPL IIx's steering for the rears will be anything close to what Logic 7 does. But I have Logic 7, so I might be a little biased. [​IMG] Sanjay knows a lot about both, so maybe I'll point him in the direction of this thread.

    Shawn- Thanks. I forgot about how *exactly* the 8000 did Logic 7. [​IMG]
     
  13. David Proud

    David Proud Stunt Coordinator

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    actually I am thinking when nobody is in the back rows I will just turn off the back surrounds and use the side surrounds only.

    I am still concerned with comb filtering and phase issues with the Widescreen mode though. What does Denon due to address these issues?

    Where in the manual does it say it duplicates it. The manual makes it sound like a DSP. All I can find is.

    Widescreen Mode

    Select this to achieve an atmosphere like that of a movie theater with large screen. In this mode all signal sources are played in the 7.1 channel mode. Including dolby pro logic, dolby digital 5.1 channel sources. Effects simulating the multi surround speakers of movie theaters are added to the surround channels.

    Ah I also found this..

    EFFECT:
    This parameter turns on the effect signals with multi surround mode speaker effects on or off. If it is turned off the sbl and sbr channel signals are equivalent to the SL and SR channels.

    EFFECT LEVEL:
    This sets the strength of the surround effect.
    The level can be set in 15 steps from 1 to 15. Lower the level if the sound seems distorted or in a wierd location.

    Interesting this effect setting is. With EFFECT off it bypasses the DSP. With effect on it uses a dsp and does some things to create some individual sounds in all 4 speakers in the rear.




    I also think it would beneficial to calibrate the back surrounds from the rear row location and calibrate the side surrounds from the front row location.

    Listererns will have "Persuasive steering", I think it is a lexicon term in which the ear picks up the loudest surround speaker and ignores the quieter one.

    Basically listeners in the front row will be keyed into the two side surrounds for all there action while and listeners in the back row will be keyed into the back surrounds for there surround action.

    When I have two rows of company on goes denon Widescreen mode to duplicate side surrounds to rear surrounds.

    When I have just me I will turn on basic 5.1 DD/DTS. and the back surrounds just sit there are relax.
     
  14. Kevin C Brown

    Kevin C Brown Producer

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    David- I can't tell you exactly where in the manual, because it was in the 3802 manual I read, oh, about 18 months ago. [​IMG] (Was looking at the 3802 as a pre/pro for a short time.) But I do remember that it was in the "fine print" and not in the normal text of how to operate. I remember it being a footnote at the bottom of a table or something describing the surround modes it had. I do have a copy of it somewhere, so I will take a look around. (I even remember it being in the Denon/Yamaha/Harmon Kardon folder under my coffee table!)
     
  15. RichardHOS

    RichardHOS Second Unit

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    (1) Yes, the Denon widescreen mode will have problems with comb filtering and a smearing of the soundstage. Denon has done nothing to address this.

    (2) Why would you only want 5.1 with no rear row listners? 7.1 is great for a single person, with better envelopment than 5.1, especially when used with a SOTA ambience extraction processor like the Lexicon's.

    (3) True steered 7.1 would probably still offer the most enveloping and convincing soundstage for multiple rows of listeners.
     
  16. David Proud

    David Proud Stunt Coordinator

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    Thanks Richard. That is what I was looking for. well it looks like the Lexicon will have to be my next big purchase.

    I guess my big decision will be should I wait for the Denon AVR-4804 with DPIIx for true 7.1 steering or should I just go ahead and get a lexicon processor.

    What Lexicon processor would be on par or better than the best Denon model Dacs?
     
  17. ChrisLazarko

    ChrisLazarko Supporting Actor

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    I just read up a little bit on the Lexicon processors and it looks like Kevin has some good points which are true. The Lexicon processor is your best bet I think with a seperate amp. Good luck on your setup.
     
  18. David Proud

    David Proud Stunt Coordinator

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    I just got though reading Dolbys website and it says the following.

    23. Why does Dolby Pro Logic IIx sound more natural than competing formats?

    A few factors contribute to this. One is the newly developed approach in steering logic design, which affords unprecedented smoothness and precise dynamic behavior. Another is the lack of signal coloration achieved by employing the simplest audio path, with as little filtering of the audio as possible.

    I would love to see a logic7 comparison to DIIx and see who wins.

    I imagine Lexicon Controllers could be upgraded to DPIIx.
     
  19. Harry Lincoln

    Harry Lincoln Stunt Coordinator

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    If the Denon Widescreen mode was a duplication of the surround speakers, it would give the same results as configuring the 3803 for 7.1 and setting the back speakers to 'non mtrx' mode on a DD or DTS 5.1 track.
    Why would they bother to include this mode if that was the case? I think there is some DSP going on for sure in the widescreen mode.

    If you use a pre/pro and amp is there any reason you couldn't achieve what youre after by using a 'Y' splitter on the pre outs and feed each surround signal to two amp channels?
     
  20. David Proud

    David Proud Stunt Coordinator

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    looks like widescreen is infact a dsp. what does it do other than duplicate sr channels?

    look at the info from
    http://www.usa.denon.com/catalog/pdfs/AVR4800LIT.pdf

    Widescreen 7.1 Channel Playback of Conventional
    Sources - A Denon Original Technology
    Denon's new Widescreen 7.1 function provides thrilling 7 speakers (plus
    subwoofer) reproduction of conventional stereo, matrix encoded, and discrete
    5.1 program sources. This proprietary Denon DSP function provides full
    panoramic surround presentation, utilizing the three front loudspeakers, the
    two surround loudspeakers, and if configured, the surround back loudspeakers.
    Enjoy total 360 degree surround immersion, with movie soundtracks and your favorite musical performances also.

    EFFECT:
    This parameter turns on the effect signals with multi surround mode speaker effects on or off. If it is turned off the sbl and sbr channel signals are equivalent to the SL and SR channels.

    EFFECT LEVEL:
    This sets the strength of the surround effect.
    The level can be set in 15 steps from 1 to 15. Lower the level if the sound seems distorted or in a wierd location.

    This is what it sounds like to me. With effect turned off it is a simple duplication.

    With effect turned on you can alter the strength of the duplication in steps from 1 to 15. NOTE it says lower the level if the sound seems distored or in a unatuaral location.

    Sounds to me like with effect on and using the effect level it is doing something to counter phase distortions and comb filtering. If you had issues it said to lower the effect level. I am curious as to what exactly the effect parameter does. Does it simply attenuate the duplication to the Surround back channels, or does it attempt to move things between the two channels by some kinda ambiant extraction dsp process.

    btw guys please see my thread on 7.1 config. I am curious about ideal speaker placements for 7.1 for Multi Row theater seating.
     

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