I think I mis-understood Dr. Marks quote, I really don't want to avoid the receiver's xover setting, so he is telling me to set the crossover in the receiver for the mains at 50Hz, how can I run them full range that way? I thought he was referring to setting the mains to full and adjust the subs crossover to 50 Hz. I'm lost here kurt, I just want to try and run the mains full range with sub engaged, should I use the double bass option in the setup menu, if so could you explain. You're saying to not avoid the AVR's bass management, correct, if so please tell me in laymans terms how to run my mains full range with sub using the AVR's bass management. Thanks a lot.
Jeff
I do not have decent familiarity with your receiver and am not sure I understand what you don't understand. Here are a couple of thoughts I hope to help.
Use the graph below as a reference. This looks like it is for an AVR crossover at about 100Hz. The yellow line represents the signal being sent to the sub and the green line is the signal sent to the mains. The red line is the combination of the sub plus the main signal, which is a nice flat line. That is how typical AVR bass management works.
In your case, you are wanting the mains to run a full range signal. Effectively, this lowers the roll-off of the main speakers to the frequency at which they naturally roll-off.
Now, with the speakers rolling off at their natural roll-off frequency, your concern is
only controlling the signal to the sub so it will complement the speakers output in the low frequencies.
On most AVR's, you can set the Main speakers to "Large", which sends them the full audio signal without filtering out the low frequencies (IOW, the crossover setting is only used for the sub output, not the main speaker outputs). If this is the case with your AVR, then setting the XO at 50Hz will only provide a LPF for the sub output and your A5's get the full range signal with out any alteration.
Setting your AVR to 50 Hz will allow for both:
1) Your sub to pick up the bass at the frequency where your speakers naturally roll-off.
2) Your sub to add the bass at a close match to the rate at which your speakers naturally roll off (24db per octave).
This is effectively the same as only using the crossover at the subwoofer amp. However, there are three benefits to using the AVR:
1) The AVR is known to roll-off at 24db/octave (you can check with PSA about the roll-off of the Amp's crossover - it may be the desired 24db/octave as well).
2) The AVR control is more exact - you know exactly where the setting is (50Hz is 50Hz). With the rotary sub control, you typically have a range of 150Hz associated with 3/4 of a revolution of a knob and the tic marks are at intervals of 20hz (minimum). I'm guessing you may get within +/- 5Hz of your desired setting on a good day.
3) The sub setting can be inadvertently altered if a dog or kid brushes against the knob (or you when reaching for other controls).
One last comment. I suspect Merlin is based on manufacturer spec's, and errs on the side of "more bass is better than not enough". IOW, if your receiver allows, try 45Hz as a XO point and see how it compares with 50Hz.