Attention all Denon 3803 Owners - Major Bass Management Flaw

Edward J M · 03-24-2003, 06:44 PM

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

Zack_R · 03-24-2003, 11:17 PM

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?

Chuck Kent · 03-25-2003, 04:35 AM

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.

Edward J M · 03-25-2003, 06:09 AM

Quote:

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 setting, is now 6db too high?

Edit: Revised to clarify the description of the problem.

No - the sub level control will ramp both the low passed bass AND the LFE channel up and down. The problem is that it allows the LFE level to be set at a much lower level than the low passed bass level. This should never be allowed to occur in a high pass / low pass Small speaker configuration.

So low passed bass is never "too high" or "too low" - assuming you calibrated correctly, the level of the low passed bass will always be correct.

It is the LFE channel that could be out of whack in relation to the low passed bass.

Consider my following true example, just using the mains for simplicity:

Reference Level (00) calibration with internal test tones yielded -2 for the mains for 75 dB at the couch. I then arbitrarily set the sub level at -8 and adjusted the plate amp on the sub to get 78 dB at the couch. The result if you own a Denon 3803? Your LFE channel is now operating at a FIXED DEFICIT of 6 dB on all source material at any given Master Volume setting.

How does the user fix this? Set the sub level to -2 (the same as the mains) and readjust the sub plate amp to once again obtain 78 dB on the meter. Results? Low passed bass and the LFE channel are now operating at the SAME relative level for any given Master Volume setting.

The difference on certain DVDs is simply astounding, depending on which channel the bass was derived from. For example, the bass in the Pod Race on SW Episode 1 is almost exclusively derived from the LFE channel. On my system, the Pod Race was completely underwhelming with the new Denon 3803 because I was operating at a 6 dB deficit on the LFE channel, despite obtaining 78 dB on the sub level during calibration. After resetting the sub level to -2 and recalibrating once again to 78 dB (the SAME SPL as before), the Pod Race was back to being the bass monster I always remembered.

Another major difference was on The Haunting (dts). The famous Chapter 10 - Creaking Pipes. The door knocks are primarily derived from the surround channels and were suitably powerful and strong. However, the extended ultra deep bass note when the ghost comes into the room and causes their breath to condense is derived exclusively from the LFE channel and was completely underwhelming - not at all how I remembered it. Once again - after resetting the sub level to -2 (the same as the mains)and recalibrating to 78 dB, that note was totally back to being the room quaking, ear pressurizing beast I always remembered.

I'm 99% positive I've nailed this diagnosis. But I'd like others to try it on their 3803s to see if the problem is pervasive. If it is, Denon should recall all the affected units and fix them at no charge.

Regards,

Ed

MatthewJ S · 03-25-2003, 07:43 AM

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......

**HTF Ads**

wayne nagle · 03-25-2003, 07:55 AM

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

wayne55@msn.com

Seth_L · 03-25-2003, 08:38 AM

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

Edward J M · 03-25-2003, 09:33 AM

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

Brad Newton · 03-25-2003, 11:27 AM

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?