Originally Posted by Tim Glover
Hey guys...I am having some issues dialing in my subwoofer. Using the analogue multichannel outs on the Oppp 105D to the analogue Multi in on my Pioneer Elite SC-57 AVR. At first I had both components with the same settings. Speakers to small & 80hz crossover. And the Elite has an option to increase the sub gain when using the Multi analogue so I did this. +10db.
Just felt the LFE was too hot and muddy as well. Too much bass and not as tight or defined. Did some reading on here and someone suggested changing Oppo speakers to Large and Sub yes.....leaving the AVR where it was. I also went back to the default setting of 0db for the sub instead of the +10 gain for analogue. After this change it was much much better. I played several familiar scenes Sunday afternoon and it was deep, tight, and powerful.
BUT...tonight I was listening to some concert BDs and it felt like the LFE was totally off. Anyway, I can just manually tweak it for music.
However somehow tonight, I just couldn't reproduce what I heard the other day. I know that sounds NUTS.
Do you guys think there is some double processing going on? I own dual SVS PB 12/plus 2 subs but only one is working at the moment.
Just for fun I plugged in the HDMI and let my AVR decode. For starters, it's much louder. Had to really lower the volume. IDK, the bass was overall stronger and tighter at times using the HDMI so I know there is something I am overlooking or doing wrong.
Suggestions? I have been so frustrated I am ready to just forget the whole thing and listen to my plasma TV speakers.
Take a step back and think about what you are doing here. With a Crossover active in BOTH the OPPO and the AVR you are doubling the processing. Effectively you are steepening the slope of the Crossover. Not good.
The idea is to only do the Crossover processing in one place. If you want the OPPO to do it, then you must set speakers to LARGE in the AVR. If you want the AVR to do it then you must set speakers to LARGE in the OPPO.
Furthermore, you must make sure the Sub itself is not applying a Crossover to discard higher bass frequencies. Either disable the Crossover built into the Sub, or crank it up to the highest frequency to get it out of the way as much as possible.
And if you have any other electronics between the AVR and the Sub you must make sure there is no Crossover active there either!
OK, next is Sub boost. You absolutely have to check this with an SPL meter. I also recommend you check it using the test tones on a calibration disc. For example the LPCM test tones on AIX Audio Calibration, Blu-ray.
When all speakers are set to LARGE in the OPPO, the RCA Sub output of the OPPO needs +10dB boost, external to the player, to match the output of the other RCA jacks. (If you are using the XLR jacks for LF/RF speakers, they are an additional 6dB hotter.)
If any speakers are set to SMALL in the OPPO, then the bass boost needed is +15dB instead of +10dB.
The bass boost needed is usually accomplished by adjusting the Volume knob on the Sub itself, but when passing the Sub signal through an AVR, the AVR usually adds +10dB boost itself, by default.
You can avoid being confused by these details if you just take the simple step of checking what's actually getting to the Sub with an SPL meter and a calibration test track like that one from AIX. Once the Sub level measures the same as the main speaker levels you are good to go.
The difference between what you heard with the movie disc vs. the music is likely that the movie disc had bass in its LFE channel (the .1 of 5.1 or 7.1) whereas the music disc may very well have nothing in the LFE channel -- all its bass was in the main speaker channels. And thus the music disc was a more sensitive test of whether the Crossover was set up correctly.
Lastly is the issue of picking the best Crossover frequency. The physical positioning of your Sub, and the room geometry, alters how bass "standing waves" couple with the room. At some frequencies you will get resonance peaks. At others cancellation nulls. It's not uncommon to see a swing of 12dB in the bass you hear at different frequencies. Adjusting the Sub positioning or treating the room to damp bass reflections can tame this. And picking a different Crossover frequency can also tame this by moving bass to the Sub earlier or later in he frequency curve. (The mains and Sub are at different locations, so couple differently.)
If you have a big Room Response problem like this, that can ALSO show up as perceived bass quality differences between movies and music. Why? Because movies and music emphasize different bass frequencies.
That AIX disc has another sensitive test to check for unequal bass response. Its Crossover test sends a bass frequency sweep to just the mains. At the high frequency end all of that comes out of the Mains. At the low frequency end it all comes out of the Sub due to the action of the Crossover.
If everything is set up correctly, that sweep should be heard as constant volume from end to end (except for the very lowest bass which is more felt than heard).
Bass calibration and room setup are complicated topics. See the Subwoofer forum here for more information and advice on test tools and methods.