Attention all Denon 3803 Owners - Major Bass Management Flaw

Discussion in 'AV Receivers' started by Edward J M, Mar 24, 2003.

  1. Edward J M

    Edward J M Cinematographer

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    Edit - description of problem updated for clarity: The Denon 3803 will not automatically equalize the low passed bass and the LFE channel, and it thereby allows the user to unknowingly create a large fixed level disparity between the two bass sources. This is not conventional bass management, and it is clearly a design flaw on Denon's part.

    Normally, if the speakers are set to small, the subwoofer level control adjusts both the low passed bass AND the LFE channel equally and simultaneously.

    If the user calibrates to a 75 dB Reference Level at Master Volume 00 using the internal test tones, the individual settings for the mains, center, and surrounds are obviously fixed. Conversely, it is a common practice to arbitrarily select a subwoofer level setting (say -6 on a scale of -12 to +12) and then adjust the subwoofer plate amp control to achieve 75-78 dB on the SPL meter when calibrating. This practice is done under the assumption that the subwoofer level control will equally adjust both the low passed bass AND the LFE channel bass.

    However, if said subwoofer level setting is actually an LFE channel control ONLY, then any difference between the subwoofer level setting and the settings for the other high passed speakers by default becomes a FIXED disparity between the low passed bass level and the LFE level for any given Master Volume setting.

    For example, if the average Reference Level settings for all the high passed speakers is -2, and the user arbitrarily selects -7 for the subwoofer level control and adjusts for 75 dB at the plate amp, the LFE channel will ALWAYS run 5 dB cooler than the rest of the system levels at any given Master Volume setting.

    This is a new AVR for me, and I was wondering why my bass levels were wandering all over the place on certain DVDs and also were vastly different between DVDs. The reason why is because I was experiencing low passed bass at the proper playback level, and LFE bass (in my case) a huge 6 dB lower. When the bass in the DVD was derived from the LFE channel only, the bass was very weak. When it was derived from the high passed surround channels, it was suitably strong. You can imagine the consternation this caused me until I figured it out.

    Bottom Line: If you own a Denon 3803, you had better make damn sure the internal subwoofer level setting is EXACTLY the same as the internal setting for the mains. When I did this, all my bass problems went completely away.

    I have specific examples of DVDs with time stamps if this thread generates any interest.

    And just to avoid any unproductive tangents, this was NOT related to the LFE peak bass limiter control, which was correctly set at 0 (the highest setting). This was also NOT related to the DD Dynamic Compression Circuits in the DVD Player and the AVR-3803, both of which were set to Off.

    I think Denon SCREWED UP and accidentally left the LFE channel level circuit in place instead of the overall subwoofer level control when they eliminated the LFE leveler control when they introduced the 3803.

    Regards,

    Ed
     
  2. Zack_R

    Zack_R Stunt Coordinator

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    Does this mean that if you compensate for the -6db LFE for movies by increasing the receiver sub output that your redirected bass, due to the small speaker seting, is now 6db too high?
     
  3. Chuck Kent

    Chuck Kent Supporting Actor

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    Very strange...

    I have a 3803 and have not experienced this issue. I am not currently running any speakers as "Small" but when I have tested my bass management, I did not notice this trouble with any setting, 2 channel or otherwise.

    One question that comes to mind is whether you have tried a processor reset. It is well known that Denon's can benefit from the reset when operating quirks appear. Is it also possible that your unit may be defective??

    Hopefully some others will check their 3803s and let us know their results.
     
  4. Edward J M

    Edward J M Cinematographer

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  5. MatthewJ S

    MatthewJ S Supporting Actor

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    You should pose this as a question to "Denon Jeff" on the "special guests" section of AVSforum.....He hasn't been responding lately because of all the negative posts and problems people have been experiancing with this (among other ) units, but he may be able to adress if you are correct or if your unit is malfunctioning......
     
  6. wayne nagle

    wayne nagle Auditioning

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    3803 and polk LSI series:

    I have a Denon 3803 with the polk LSI series:

    LSI25s for Front
    LSI/FX for Surround A
    LSI 9s for Surround B
    LSI 9s for Surround Back
    LSI c for Center
    and 650 for a sub.

    I am having volume problems. The Denon doesn't seem to push high volume levels like my old Sony did. Is this because the Polks are 4 ohm speakers? The Denon site said I could push 4 ohm speakers but the manual says 6-8. Should I get an amp for my polks?

    Thanks

    Nagle

    [email protected]
     
  7. Seth_L

    Seth_L Screenwriter

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    Wayne,

    You could try to start a new thread instead of asking in Edward's.

    Edward,

    I wish you luck. I found a bug in the Onkyo 898 I bought, confirmed it with their tech support/engineers. When I posted warnings of the problem here and on AVS all I got were vehement denials that the problem was not real from fanboy owners. Put on your flamesuit and get ready for a bumpy ride.

    Seth
     
  8. Edward J M

    Edward J M Cinematographer

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    Thanks, Seth. I am just trying to help other 3803 owners get the most from this AVR. If the owner is aware of this bass management flaw, then they can accomodate for it and everything will be OK.

    Actually, I was thinking this morning if I take this seprate LFE channel calibration concept a step further:

    When I calibrate to Reference Level, and set the speaks to 75 dB all around and then adjust the sub plate amp to 78 dB (disregarding for the moment the actual sub level setting in the AVR) what I am actually accomplishing with the 3803 is I'm setting ONLY the low passed bass 3 dB "hot".

    Now if my mains end up at -2 for Reference Level 75 dB calibration, in order to also run the LFE level 3 dB "hot", I would actually need to set the sub level control to +1 and THEN adjust the sub plate amp to obtain 78 dB at the mic.

    Now, BOTH the low passed bass AND the LFE channel will be running 3 dB "hot" with respect to the mains, and will also be running at the same exact level with respect to each other.

    Do you follow my logic here?

    What I'm accomplishing manually with the 3803 is what a normally functioning sub level control does automatically when the speakers are set to small. It automatically sets the low passed bass and the LFE channel to the same level.

    Anyway, check these numbers out for The Haunting DTS:

    Test #1:
    Master Volume Setting: -10
    Mains Reference Level (75 dB) Calibration Setting: -2
    Sub Reference Level (78 dB) Calibration Setting: -10
    Door Knocks: 110 dB
    Extended Bass Note: 98 dB

    Test #2:
    Master Volume Setting: -10
    Mains Reference Level (75 dB) Setting: -2
    Sub Reference Level (78 dB) Calibration Setting: -5
    Door Knocks: 110 dB
    Extended Bass Note: 103 dB

    Test #3:
    Master Volume Setting: -10
    Mains Reference Level (75 dB) Calibration Setting: -2
    Sub Reference Level (78 dB) Calibration Setting: 0
    Door Knocks: 110 dB
    Extended Bass Note: 108 dB

    Notice the volume on the door knocks remains unchanged, and yet the volume on the extended bass note increases each time the sub level is increased, despite the fact the the overall sub Reference Level calibration SPL remains constant at 78 dB because I readjusted the plate amp control each time.

    Here are the numbers for the Pod Race with similar results:

    Test #1:
    Master Volume Setting: 00
    Mains Reference Level (75 dB) Calibration Setting: -2
    Sub Reference Level (78 dB) Calibration Setting: -10
    Canyon Exit: 100 dB

    Test #2:
    Master Volume Setting: 00
    Mains Reference Level (75 dB) Setting: -2
    Sub Reference Level (78 dB) Calibration Setting: -5
    Canyon Exit: 105 dB

    Test #3:
    Master Volume Setting: 00
    Mains Reference Level (75 dB) Calibration Setting: -2
    Sub Reference Level (78 dB) Calibration Setting: 0
    Canyon Exit: 110 dB

    In this case the bass from the Pod Race is obviously exclusively derived from the LFE channel.

    In a final analysis, my Reference Level calibration settings for the 3803 will be:

    Mains: -2 at 75 dB
    Sub: +1 at 78 dB

    This will ensure both low passed bass AND the LFE channel are running 3 dB "hot" compared to the high passed speaker levels.

    To anyone else who owns a 3803 - I strongly advise you run similar tests and confirm for your self and recalibrate accordingly as needed.

    Regards,

    Ed
     
  9. Brad Newton

    Brad Newton Second Unit

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    Exactly what does this mean to the average home theater person, like me that doesn't understand totally what you are saying???? Are you saying not to purchase this unit?
     
  10. BrianWoerndle

    BrianWoerndle Supporting Actor

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    Does anyone know how this works in other sources? If you adjust the 'subwoffer level control' individually for another source that has a stereo signal and no LFE, then it would do nothing?

    Are all your adjustments using the master level adjustments in the main setup menu?

    What happens when you adjust the input specific subwoofer level? What would happen if you set the master sub level to +1, and then adjusted the input specific level to an arbitrary level of -7, then adjusted the plate amp control to 78db?

    I agree this is a big design flaw. I am going to have to do some test on my 3803 to see how this works. I am curious about the input specific controls. Some of my games I like to have a little bit more bass, so I adjust the input specific sub level that way I don't touch my reference level DVDs, but accoriding to this, it will do absoultly nothing.
     
  11. EricSm

    EricSm Stunt Coordinator

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    It's really funny you should mention this. Just this weekend I came to the same conclusion(albeit not as detailed) on my Denon AVR-1803. I had taken the sub level down to -4 or so and adjusted at the plate amp on my sub, using the avia calibration tools to match the output levels. I noticed on a few movies that the bass was really weak on some parts. I found it very odd and disconcerting. I went back to the avia disk and did the front left frequency sweep and everything checked out fine. I then decided to do the isolated subwoofer sweep and I was astonished at how much lower the overall volume was than when you would do a frequency sweep with one of the front mains crossed over. I thought: this confirms it. But why... I couldn't figure it out. I thought whatever "tone" was being used to match the sub level to the front level didn't go low enough to account for the crossover and thus when I was setting it, I was still getting output from the front speaker in addition to the sub that was "falsely" boosting the db readings. So I tried the Sound and Vision disk. It confirmed that the subwoofer was properly calibrated. It was driving me batty, because the LFE channel was absolutely whimping out in movies. Yet, like Edward was saying, there was bass, just not in the all the places it should be. Well, after more playing around, I essentially came to the conclusion that lowering the subwoofer level at the receiver was the culprit. I promptly boosted it back to be in line with the mains and the problem went away.

    Really could've used this thread about a week ago ; )

    Great post.
     
  12. Edward J M

    Edward J M Cinematographer

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    Brian:

    All my adjustments are using the master level adjustments in the main set-up menu.

    As you know, this master level governs/controls all of the other individual user settings for various input configs - stereo, direct, pure direct, DD/DTS, etc.

    Let me be clear on the what I consider to be the crux of this design flaw:

    The bass management circuit does not automatically set the low passed bass and the LFE channel bass to the same relative level, which is how a normally functioning bass management circuit works. The old standby method of setting the AVR sub level to some arbitrary negative number and adjusting at the plate amp to obtain 78 dB for Reference Level calibration DOES NOT WORK with the 3803 and can result in a fixed disparity between the low passed bass the the LFE channel bass.

    The only way to properly set the sub level setting for the 3803 is as follows:

    1) Initiate the test tones in the set-up menu and obtain 75 dB for all the speakers except the sub. Note the setting for the mains. In my room it is actually -3.

    2) Determine how "hot" you want to run the sub. Most people pick 3 dB "hot" for HT applications, so let's use it in this example.

    3) Take the current level setting number for the mains (-3) and add to that number how hot you want to run the sub (+3). The resultant number is what you should set the sub channel level to. In this case it would be: -3 + 3 = 0.

    4) After setting the sub channel level to zero, adjust the sub plate amp so the meter reads 78 dB.

    5) Your 3803 is now calibrated 3 dB hot for both low passed bass AND for the LFE channel.

    Regards,

    Ed
     
  13. Edward J M

    Edward J M Cinematographer

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  14. BrianWoerndle

    BrianWoerndle Supporting Actor

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    Edward,

    Am I correct in thinking that in non 5.1 sources that the subwoffer level adjustment does nothing? Because all of the bass going to the sub is redirected bass from the main speakers since there is no LFE track.
     
  15. Mike Up

    Mike Up Second Unit

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    Edward,

    Sorry, but you just confused the hell out of me with your explanation.

    Are you trying to say that the subwoofer level, master level and sound mode individual level, only adjusts the LFE channel level and NEVER adjusts the actual bass level that's directed from the "SMALL" speakers to the subwoofer output? Therefore, it always leaves the "DIRECTED BASS" at a 0db calibration level(referenced to where it would be on the subwoofer level adjustment if working correctly)?

    If that's the case, I think your unit is defective or needs a reset. I have three test discs for sub levels, and the AVR-3803 has proven to be calibrated SPOT ON.

    My subwoofer level works as a subwoofer level should, not as a LFE channel level "ONLY" adjustment. Since I mainly listen to DPL 2, 7 channel stereo, and stereo, I know for a fact that my subwoofer level works correctly since none of these sound modes has a dedicated LFE channel.

    I also know that my LFE channel level works correctly as I have confirmed that with DTS and Dolby Digital test signals. The Subwoofer channel definitely does not act as a LFE level control "ONLY". The subwoofer channel adjusts the levels of both redirected bass signals from small speakers and the LFE channel bass.

    Chuck had very good advise and I would recommend you follow it by resetting your receiver. He had strange problems, as you, and by resetting the receiver, the problem was corrected. After all, these are just glorified Home theater computers. [​IMG]

    If you need help in experimenting or setting up, I'd be glad to help.

    BTW, if you had all speakers set to small, yet were using your main front speakers set to large, while keeping the subwoofer option set to "LFE+MAINS", you could be having Cancellation issues with the redirected bass since it's being played from the large speakers and the subwoofer. I know, I had those issue. I spent a week testing, moving, relocating and adjusting for the best bass output in my house. To say the least, I was very impressed by the Denon's bass management.

    The only thing I don't like is that the subwoofer is always active in modes other than DTS, DD, or widescreen, whether the main speakers are set to large or small. The subwoofer option(LFE or LFE+MAIN) is only valid for DTS, DD, and Widescreen sound modes. The subwoofer can be shut off individually for each sound mode by going into the subwoofer level and going to the min level where it says "OFF". That was my only disappointment as I felt that the subwoofer option mode should had applied to all sound modes as did with my Yamaha receivers. Denon does make mention of this in their manual as to tell you this is the correct operation of the receiver.

    Well, if you need any help, just ask and good luck in rectifying your problem.[​IMG]
     
  16. Edward J M

    Edward J M Cinematographer

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  17. Chriss M

    Chriss M Second Unit

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    an easy way to test this would be with the Avia disc. All of the subwoofer test signals are played back through the main channels. There is no LFE signal for any of the sub test patterns, with the only exception being the one frequency sweep specifically labeled as "LFE". In fact, there is one test tone for the sub for each of the 5 channels, so you would be able to independantly test for the problem on each channel.
     
  18. Edward J M

    Edward J M Cinematographer

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  19. EricSm

    EricSm Stunt Coordinator

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    Chriss M,

    That is exactly what I did with the avia disk. And the LFE sweep was considerably lower than it should be. Yet, with the crossover on, a sweep of any of the other channels was spot on. It was all the verification I needed.

    I'm not sure that it is a processor error, but if it isn't it should be clearly stated in the owner's manual exactly what the control is doing. Then again, judging by the current state of the manual that's not much of a surprise.

    I'd be interested to see other Denon xx03 owners who have the Avia disk do this simple test:

    Set the subwoofer volume to a significantly low number (-6) on the receiver, then calibrate your sub at the sub plate to the front left speaker using the appropriate Avia section. Then do a frequency sweep on that front left channel-- this of course assumes you are using the subwoofer's internal bass management and have the fronts set as "small." Note your readings. Then, do a LFE sweep and see if those readings aren't significantly lower than the readings you were getting on the previous sweep. If this issue is universal, that I would guess that they will be quite a bit lower on the LFE sweep.


    As Ed clearly points out, it's easily fixable, but it's critical to understand what that subwoofer level control on the Denon receiver is doing.

    -Eric
     
  20. Mark All

    Mark All Second Unit

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    Hi Ed,
    I haven't had any bass management problems specific to the receiver, but then again I haven't used small speakers all around. Thanks for posting about the adjustments necessary with that type of setup--may come in handy for me later on. I'm not sure if it's a defect in design with the Denon though if it can be adjusted for when using a set-up disc. But, the manual could be better written for speaker level settings as it's not all that helpful now. Frequency sweeps and level setting with a test disc show everything's okay in my system. I run the four corner speakers as full range and the front center and back center as small. The problem I have is that my mains go much lower than my subwoofer, so my subwoofer setting is set at +8 for movies. I would strongly encourage anyone to get an Avia or S&V set-up disc and an SPL meter to check things out in their systems for themselves.
     

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