Odd Woofer settings effect on Yammy RX-Z9 (1 Viewer)

[Kaj]

Hi,

While I’m waiting for my next Z9 to arrive and my other problems to be fixed, I am trying to set up and take advantage of my time and current Z9 to find out everything I can.

The Z9, allows you to hook up two Woofers to two pre-out jacks, Left(Front)/Right(Back). In the setup menu, you can tell the Yamaha to setup the subs you’ve connected in:

STEREO (a sub in each of the left and right sound fields),
FRONT and BACK (a sub in the front and rear sound fields)
MONAURAL (One Sub)

Now, I have two subs, one in the front right of the room, and one in the front left of the room. So I originally set the Z9 on STEREO. Sounded all good (I’m not complaining about anything, just curious).
But then, out of curiosity, I set the Z9 to MONAURAL for the Sub woofer output with both my subs still connected, the same as before.

The subs to my surprise sounded noticeably louder, slightly cleaner and tighter!

What is the difference between the Three settings then? What does the Z9 do to the LFE or .1 signal being sent to the Sub in STEREO or FRONT and BACK mode. Moreover, what makes the difference when the Z9 then, is set to MONAURAL mode.

NOTE: I think when the Z9 is set on MONAURAL, it still outputs via both the Left/Right Sub Pre Out jacks, but the Signal is exactly the same from both left/right so it doesn’t matter which plug you hook up the sub(s) too.

Why would I then set the Z9 on STEREO, or FRONT and BACK (they both were slightly more subdued compared to the MONAURAL) when they don’t seem to be as good, or am I missing something?
And how/what is the Z9 doing/processing in the two first settings as opposed to the standard MONAURAL setting?

I’m curious to find out

thankyou

 

[Chad B]

In mono mode, both the LFE and each channel's (that is set to small) bass is summed and sent out mono. In stereo, the LFE is still sent out mono, but the output of the small channel's bass is divided up between right and left and sent out stereo. In other words, if you have small surround speakers, the redirected bass from the surround left speaker is output to the left subwoofer output (same for the main L/R). In front/back mode, the LFE is still mono and the small channel's bass is divided up between the front and rear zones; so if you have small mains it will redirect their bass to the front sub output, and if you have small surrounds it will redirect their bass to the sub back output. I believe some receivers and preamps output bass from each channel to the sub output whether that particular channel is set to small or large, but I doubt that the Z9 is that way.
I'm not sure why it would sound tighter and cleaner in stereo, but it might sound slightly louder in mono because of mutual coupling (the output from 2 subs playing the same signal can have slight acoustical gain at lower frequencies depending on where they are placed in the room over the output of one sub getting a higher electrical signal).

 

[Kaj]

thankyou, i thought as much, i thought i'd just check

thanks

KJ