Question about subwoofers with my receiver (Pioneer VSX-834)

[HoneyBunny]

If 3 channels and 1 subwoofer is 3.1, why can't I select 3.2 channel audio when I plug in two subwoofers?
Specs:
Front L,R: Polk T50
C:Klipsch Bookshelf 6'' (dangerous to not use a real C channel speaker?)
Subwoofer L:Polk 100W 10'' R:Klipsch 12''

Edited April 15, 2022 by HoneyBunny
Better wording

[circeseye]

both should work on 3.1. the same signal gets sent to both outputs always . if one isnt working its most likely a bad jack. there isnt an option to turn one on or off, only turning both on or off

[kirashi]

29 minutes ago, HoneyBunny said:

If 3 channels and 1 subwoofer is 3.1, why can't I select 3.2 channel audio when I plug in two subwoofers?
Specs:
Front L,R: Polk T50
C:Klipsch Bookshelf 6'' (dangerous to not use a real C channel speaker?)
Subwoofer L:Polk 100W 10'' R:Klipsch 12''

Probably because that's not how your AV Receiver works, as per page 12 of the user manual.

https://intl.pioneer-audiovisual.com/products/av_receiver/vsx-834/

Quote

9. SUBWOOFER PRE OUT jack: Connect a powered subwoofer with a subwoofer cable. Up to two powered subwoofers can be connected. The same signal is output from each of the SUBWOOFER PRE OUT jacks.

 

[HoneyBunny]

14 minutes ago, circeseye said:

both should work on 3.1. the same signal gets sent to both outputs always . if one isnt working its most likely a bad jack. there isnt an option to turn one on or off, only turning both on or off

They are both working just fine I was just wondering if the whole .2 thing would make the receiver capable of differentiating between sub frequencies coming from the left or the right individually, theoretically speaking, perhaps in a more advanced model of receiver?.  Thank you for the polite reply

[cmndr]

TLDR: You're fine, just plug the subs in and enjoy. Place the subwoofers in different parts of the room.

 

Most receivers only do X.1 processing. As in there's no/minimal config for TWO subwoofers and the AVRs pretend it's just ONE subwoofer. It's not too far from taking a y-cable and plugging it into just one of the two outputs and then plugging your subs into the y cable. Even on my "fancy" AVR with a bunch of features the only extras I get are separate time delays per-sub and separate software level sets per sub. The EQ is applied to both subs. There are benefits to having two subs though, more even bass response from more seating locations. In some rooms (mine was one) you can get cases where the reflections from the walls result in some frequencies being amplified and other frequencies basically being cancelled to nothing. Two subs in different locations means that the reflections from the walls won't be as big of a problem.



What I would suggest doing:
0. Be thoughtful about subwoofer location. In general opposite corners or far left/right are the best positions for your subs though it depends on the room.
1. Configure the volume on your subwoofers to a reasonable level, one at a time using the gain knobs on the subs.
2. Play with phase on your subs. I ended up trial and erroring A LOT to get my subs dialed in. I ended on on 45degrees and 135 degrees for my two subs. (left, right respectively though both receiving the same signal).
3. Run the EQ/config software on the subs.

 

 

As far as differentiating left/right signals on your subs... it IS possible to do that by running the line meant for your L/R speakers to the sub and then passing it out from the subwoofer to your L/R speakers respectively (run the system "without" subs in the AVR config). There's SOME benefits to this but they're mostly mild. Below 80Hz or so it's VERY hard or impossible to tell where a sound frequency is coming from and below 20Hz you mostly feel it. It's usually better to just have a mono signal sent to the subwoofers and to tune (location, phase setting, eq, etc.) the subwoofers for a good, even frequency response. If you're crossing over your tower speakers at 60Hz or so (which means that your subwoofers will be putting out VERY LITTLE signal by 80Hz), then there's almost no benefit to fiddling with 'stereo' - heck most content is mixed in mono for low frequencies (so you don't blow out a headphone user's ear).

As an FYI, with your set up, you might be better with one BIG subwoofer that digs deep over two mediocre subs (not sure what models you have).

-----

 

For what it's worth I spent a few hours just this week getting my two subs to work together. I FINALLY FIXED MY ROOM MODES! No more dips at ~23 ~46 and ~90Hz. The bass seems to be smoother than what I'm getting from my L+R speakers now in terms of frequency response.
 

[circeseye]

cmndr is correct
placement is a big difference. also placement depending on location of air port can have differences.

a good example, if you have a sub facing a open doorway you will loose sound. you want the sound to "bounce" in the room, not outside it.
corners are a good placement if the air port in on the bottom or on the back sitting about 6ish inches from the walls
front air ports can be placed almost anywhere in the room. these you do the sub crawl moving then around the room to get the most out of them
also when running 2 subs do not have them sitting directly across from each other, more like one front right of room and the other rear left