I’m surprised there is a signal to the sub even when setting speakers to Small as that is not what is indicated in the manual concerning SACD playback of 2CH DSD signals. But, if it works, great. Unfortunately there is no crossover setting and no telling where it is fixed but one would assume 80Hz.
The DSD signal is already being decoded and converted to PCM before being output from the analog ports to the receiver. When using the 5.1 analog outputs into the analog 7.1 CH IN ports, the receiver does nothing with the signal and only volume is available for adjustment.
When playing 2CH discs and using the 2CH analog ports, you may need to switch audio output from 5.1 CH to 2CH in the player if there is no signal output. If connected to the receiver’s 2Ch analog CD port, the receiver will do an analog to digital conversion for processing and then a digital to analog conversion for output. Unlike the analog 7.1 CH IN, the 2CH analog ports can be bass managed by the receiver and numerous sound modes can be applied to the signal. Be sure to change back to 5.1 CH setting in the player for multichannel discs if having to switch to 2CH for the 2CH SACDs.
You will always notice more bass from 5.1 discs because they contain a Low Frequency Effects channel dedicated to low bass output. A player, AVP or AVR processing 2CH signals to speakers set to Small is simply using a crossover to send the lower frequencies of the two channels to a subwoofer. The Marantz SR6013 will do a better job of it than the Pioneer player.
While DVD-Audio’s MLP compressed multichannel PCM signals and SACD’s DSD 5.1 signals exceed the bandwidth limitations of the optical and coaxial digital ports, they do support Dolby Digital and DTS 5.1 signals from DVD-Video discs. Connect the player to the receiver with a digital cable as well as the analog cables and you can bitstream the signals to the receiver and let it do all of the processing of it.
Some with older receivers have no option but to use an older player and multichannel analog outputs. Those with newer receivers can stop fussing with older players and get a new universal player. A new universal player need only use a single HDMI output connected to a receiver to bitstream ALL of the signals. Then, all of the processing power of the receiver can be utilized.
I have had two different Denon players equipped with multichannel analog outputs connected to two different Denon receivers with multichannel analog inputs. I moved on to an Oppo universal player using HDMI for connection and then on to a couple of Sony universal players using HDMI to Onkyo receivers as I could no longer justify the price of an Oppo player or certain Denon receivers for my particular needs. So far, so good.
I’m not sure of the speaker configuration here, but the advantage of connecting a universal player to a receiver such as the SR6013 using HDMI is that 2.0, 5.1 and 7.1 signals can be up mixed into as many as 11.1 channels using an external amp for two of the channels as the SR6013 can process eleven channels but only power nine. Individual crossover and volume level for each channel can be set manually or using room correction. Various sound modes can be selected using just the channels of the input source signal or up mixing into more channels can be done. Use the 5.1 analog connections from an older player to a receiver’s 7.1 CH IN analog ports and none of the receiver’s processing capabilities will be available to you.