Originally Posted by Bob Pariseau
There may be a Crossover circuit in your Sub. Set the Sub to Bypass/Disable that, or crank it up to its highest frequency choice to get it out of the way as much as possible.
Note some subs have TWO frequency settings where one is its Crossover (limits how high the Sub will go in bass frequencies) and the other is a protection circuit (limits the lowest bass frequencies the Sub will try to reproduce). Don't confuse these two and mistakenly crank the protection frequency up too high. The protection frequency setting will be something like 20hz. The Crossover setting something like 80hz.
Must admit, I am little at sea with this. My sub, SVS SB1000, has three knobs at the back, first is volume which is at 12 'o' clock; second is phase @180hz (I am going to bring that to 0, as the speaker wiring is as it should be) and third is Low Pass Filter Crossover Frequency which is set at LFE. The AVR is connected through its sub out to its IN (LFE). I am enclosing an image.
The Crossover in the OPPO applies to its multi-channel Analog outs. So there is no Crossover on its Digital audio outs. For Digital audio like HDMI audio use the Crossover in the AVR.
I only use dedicated stereo analog in the Oppo. Will the Oppo crossover apply here?
For the Analog outs, the AVR may or may not offer Crossover. Most AVRs offer Crossover for their Stereo Analog inputs, but only higher end AVRs offer it for Multi-channel Analog input. For the AVR to do Crossover, it has to first re-digitize the Analog input. The result after Crossover then gets converted back to Analog by the DACs in the AVR. The re-digitizing and later conversion can mask the quality you are trying to here from the DACs in the OPPO. For the inputs the AVR CAN process for Crossover, there is typically an Analog "pass through" setting which bypasses the re-digitizing and processing. See the Manual and Owners Thread for your AVR.
The upshot is you have to check whether your AVR is doing Crossover for Analog input, and how you can bypass that if you want.
Note that Room Correction stuff in your AVR typically includes Crossover. If you bypass Analog audio processing in the AVR, that also means losing Room Correction for that Analog audio.
I have the Cambridge Audio CXR200, which offers crossovers for Analog setting; stereo as well as multi-channel. Multichannel however, I do not use. I have also disabled Analog processing in the AVR for Analog sources like Oppo and TT. So I think that takes care of the double processing. I was initially getting a very muted sound through Analog till an accidental press of a button on the remote got me to what you are suggesting.
CXR200 is not big for room processing, though it has one that's pretty competent. But I can live with the room correction off for 2.1. After the current set up, the first thing I checked was if the phantom centre still existed. It was there.
If you want the AVR to do that, then turn off Crossover in the OPPO. You do that by setting all speakers LARGE in the OPPO. When all speakers are set LARGE the Crossover frequency setting in the OPPO is ignored.
Now, I am a little confused here, so clarifying. I do want my AVR to do the crossover. However, if I set speakers 'LARGE' in Oppo, will it be bifurcating bass signal for the sub? Or is it that Oppo sends the signal wholesome to the AVR, which will then send the appropriate signals or waves to the LF/RF and the sub?
Thank you for all your help.