Originally Posted by M9ADE3
I have ben told that when I calibrate the system through AccuEQ i put the subwoofer volume (the circle one in front side of the sub) at 12’clock and run the calibration which i did after placing it in a new place in the front of the room 7m from my listing area because previous was 5m away placed near cabinet and it shakes. The question is after the calibration it set the sub db at -6 and after watching few shows and movies the room vibrates hard like its +6 not -6 so i went to the sub and set at 10’clock and now everything is fine BUT i have been told after calibration at 12’clock you can adjust the bass through the menu ONLY not going to the sub volume or i must re-calibration so do i need to now after lowering it to 10’clock ? its still in the same place.
The relative settings of the subwoofer volume level and the receiver's subwoofer trim setting are inter-related and the relationship is an inverse one, where raising one will lower the other. There are many different combinations of subwoofer volume setting and receiver trim setting that will yield a proper calibration level, so you're not limited to just setting the sub to 12 o'clock and letting the receiver do it's thing. I prefer to set the subwoofer volume to a point that yields a subwoofer trim setting in the receiver of about -8 to -10, AFTER calibration. This provides significant headroom to allow for raising the subwoofer trim should I find that I prefer that. Also some subwoofers with Auto-On circuits will be non-responsive if the input signal is too low. In that case, raising the subwoofer trim setting closer to 0 will be more appropriate. It may take some experimentation to find the right combination of subwoofer volume setting and receiver trim setting to optimize both of these considerations.
Most people find it easier, more repeatable and more easily reversible to change the receiver's subwoofer trim setting than to change the level on the sub itself. You can do it either way, but if you decide to go back to your original settings, that's usually much easier, and more repeatable to do through the receiver.
When you changed the subwoofer position in the room, you changed the modal interaction of the sub with the room. Your description of the 7m position causing the room to vibrate hard, sounds like you've excited a room mode that is causing excessive energy at a specific frequency, and for that energy to remain in the room to long. Turning the entire bandwidth of the sub down will improve that one room mode, but at the expense of the rest of the bandwidth of the subwoofer, which will also be turned down along with the room mode. A better solution is to try to find a better position for the subwoofer that doesn't excite so much excessive energy at a single room mode. If you don't have any measuring equipment other than the Onkyo AccuEQ, then the best technique to use is called the "sub crawl".
Originally Posted by M9ADE3
Second question please from what i understand from crossover and bass management i set my full band at 80hz, my question is the higher i go 100,120hz the more bass i’ll be getting am i right ? If yes then the more bass comes from where ? the sub itself or from the front full band speakers ?
You will not necessarily get "more bass" by using a higher crossover. When you set a crossover you re-direct the bass that would have gone to the speaker and send it to the subwoofer. This process doesn't "add" any bass to either the subwoofer or the speaker. It just determines which one plays back the bass. Since the subwoofer is the speaker you bought to reproduce the bass, and because it is designed specifically for the purpose of reproducing bass, it makes sense to send as much bass as possible to the subwoofer, because the subwoofer, theoretically, should be the best speaker to reproduce it. Also, one can then get "more bass" by simply raising the level of the subwoofer above the calibrated level.
There is, however, a limit to this. At a point around 80 Hz and above, many people can start to hear the subwoofer as a point source. They may start to hear the deepest parts of male voices, and other low to mid bass content, as coming from the subwoofer instead of the speakers. Since the sub is often not located where the sounds are supposed to originate, (on the screen), it becomes unnatural and distracting to hear these sounds come from the direction of the sub. This phenomenon is known as subwoofer "localization." Limiting the subwoofer to 80 Hz eliminates, (or at least greatly reduces), the possibility of localization.
Some people don't notice bass localization and they can use higher crossover frequencies because of that. Try experimenting with higher crossover frequencies and see whether you can localize the bass to the subwoofer. Once you've found the point where localization becomes a problem, reduce the crossover until you're below that point.
Edit: Another question that came up in this thread is whether one can lower the crossover points of the speakers below the AccuEQ system settings. In general, this is not advised. AccuEq looks for the F3 or LF roll-off point of the speakers. It sets the crossovers above this point. Lowering the crossovers will send content to the speakers that is below their F3. Most speakers will simply do nothing with that content. However, that content will, for all intents and purposes be lost as it will not be reproduced by the speakers or by the sub. In the worst case scenario, a speaker will try produce output below it's F3 and, if the levels are high enough, the speaker can be damaged. When a ported speaker tries to reproduce content below the tune point of the ports, the driver becomes unloaded and will generate massive amounts of uncontrolled excursion, with excessive distortion and driver damage.