What do you mean "Within the Denon's subwoofer settings, turn the output level up by 7dB or more." Which setting are you referring? Are you referring the Audio/Subwoofer Level menetioned below which is set to -4.0 dB?
Yes.
Volume: at 8 O clock position. (Initially, I kept at 9 O clock position, but then receiver's Audyssey setup told the volume is too high, reduce it get the dB on the screen is less than 75 db. After I put the volume at 8 O clock position, on the screen dB was ranging from 72 to 77 dB and it was green. If I increase the volume will it damage the SUb or anything?)
Not likely. If you increase the volume, do you hear the sub bottoming out?
Phase: 0 (what is this? I don't understand, I read manual, but I couldn't understand)
Phase has to do with the timing of the output sound wave as ripples in the air. They remain the same amplitude and same frequency, but the rise and fall of each ripple will occur at a different place in your room as the phase varies. Changing the phase will most likely have inaudible results from a single sub, but can cause or prevent cancellations if you have multiple subs. It's not worth worrying about in your situation.
Q Control : 0.7 (The sub manual said put it at 0.7 while starting. I don't understand what is this.)
Think of Q as how quickly a sub stops and starts. The lower the Q, the tighter the control. A Q of 0.5 is considered critically damped.
Crossover Frequency: 90Hz. (After reading what I understood about this is any sound which below to this Hz will be played by the Sub instead of the speaker. Is that correct understanding? I understand this matter only when I set crossover to IN and when I set crossover to OUT, this is controlled through receiver's settings)
I'm not familiar with that sub's controls, so I can't say which setting is correct. But in general, it's preferable to have the AVR handle the sub's low pass filtering by itself. Either turn off the sub's built-in crossover, or dial the crossover up to its highest frequency.
See, a 90Hz crossover indicates a gradual slope in output, rather than a sharp cliff. The sub is still audible over 100 Hz, a little less at 120Hz, a little less at 150, and so on. Ideally, the JBL mains are also crossed over at 90Hz, but with a
high-pass filter instead. They will still be audible at 80Hz, a little less at 70Hz, a little less at 60, and so on. (A high pass filter allows highs to pass. A low pass filter allows lows to pass. I'm sure you see how that works.)
The sub and the mains meet at the crossover point, each at -3dB, so that combined they sound the same volume. This is the way a proper blend should be. But if you have both the subwoofer and the AVR employing a low pass filter, the effect on the sub is compounded, and the transitions from mains to sub are more abrupt. This doesn't sound as good.
Audio/Subwoofer 1 Level: -4.0 dB . I didn't change this. I belive this was set by Audyssey initial setup. Should I change this to +7.0db or more?
Well, I was thinking turn it up to +3.0 to start, but by all means, feel free to salt to taste. Audyssey always sets the sub level very conservatively. Whenever I rerun Audyssey Setup, I always have to turn the LFE channel up at least 7dB from its auto configured level.
Speakers/Crossoverss:
- Speaker Selection: Individual
- Front: 40Hz
- Center: 40Hz
- Surround: 40Hz
I'd change those to 90Hz.
Subwoofer Mode: LFE+Main ( What is this? I don't understand it fully. What's the difference I'll will see for LEF vs LFE+Main. What I understood is with LFE+Main the Sub will play low range of all the speakers regardless of whether the speakers are set to large or small. With LFE, the sub will play only low range of the speakers which are set to small speakers. Is that correct? If that's correct, then it doesn't matter whether this should LFE or LFE+Main when I set all my speakers as small, right? )
If I recall correctly, LFE + Main allows the main LR to play the LFE channel as well. You don't want that. Just use LFE.
LPF for LFE: 120 Hz
- What is this? I don't understand. Is this same as the crossover frequency in the Sub's back side?
- What will happen if I keep this too low like 40H?
- What will happen if I set this to too high like 240Hz?
Low pass filter for LFE. Yes, it's the same as your sub's built-in crossover. Set it to 90Hz, and turn your sub's crossover off or turn it up to a frequency so high that it won't matter.
If you set the LPF for LFE setting in your AVR too low, your sub won't have the range it needs to play all the sounds you want it to. If you set it too high you lose definition in your sound stage and your sub will be localizable (meaning you'll be able to hear where the bass is coming from).
I found something new today. I see the good bass effects from SUB when I change the sound mode to Music (Stereo), but when set it to Movie (PLII Cinema) the center speaker is playing the most he bass effects not the sub. The sub kind of vibrates lightly. Why is that?
Dolby Pro Logic II is a virtual surround mode. It gives you surround output from a stereo source. In my experience, this usually doesn't sound as good as native. It's generally better to have your receiver play back in native mode -- meaning a 5.1 source signal (like DTS or Dolby Digital) will play back through all your speakers, whereas stereo source signal plays back only through your mains + sub, leaving the center channel and surrounds silent. If your source is YouTube, you probably don't want surround sound. YouTube audio is only encoded as stereo.
I'm not sure about the Denon, but on my Marantz there's an Auto setting for surround mode. Use that. (On my receiver, I press the Pure button on the remote to cycle from Direct to Pure Direct to Auto. I can also select Auto with the Android app on my phone.)
Final note: check your television's manual to see whether its ARC HDMI output allows multichannel output. I believe I've read that some televisions only output stereo via ARC. If yours only does stereo, you shouldn't depend on your TV's ARC for traditionally multichannel sources such as PC, Blu-Ray, or game consoles; but should instead plug those devices directly into your Denon.