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Sharing subwoofer between 2 systems.

11K views 7 replies 6 participants last post by  J_brow004 
#1 ·


The above image is my current setup. Essentially I am sharing a subwoofer with my PC speakers and AVR speakers. The AVR only has my PC and a Chromecast connected. I use the Windows sound manager to switch between the systems depending on which set of speakers I need to run. Unless I tried running my Chromecast, it is only possible for the subwoofer to get a single signal at a time. I initially tried a RCA Y-splitter into the sub due to this, but got a bad buzzing sound. To stop the buzzing I had to only have 1 of the systems plugged into sub, which means manually swapping plugs.

I then ordered a RCA switch, which is much less convenient than the Y-splitter as I have to now manually change the subwoofer over,
but better than having to swap plugs constantly (https://www.amazon.com/gp/product/B00KXVBB3Q/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1).

The buzzing inexplicably still continued. I reached out to the RCA switch company, and the CSR reached out to engineering who confirmed that the systems are not truly isolated.

I also tried plugging in the subwoofer without the ground pin, and the buzzing still continues.

Basically...is there an easy way for me to connect 2 systems into the sub and keep them isolated to prevent buzzing/humming? I thought the RCA switch, by definition, would do this, but I was mistaken.
 
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#2 ·
I don't have an answer to your question, but I hope someone does! I've been meaning to ask the same question, but you phrased it better than I could (and added a handy diagram :) )


Here are some totally random guesses I've had, which would depend of course on your particular sub's inputs & outputs), but basically you'd use your sub's inputs instead of a splitter:

1. If your sub has stereo line-level inputs, use one (usually the left channel) as LFE input from receiver. Use the right channel as the input from your PC - from what I've read, the right is still a valid mono input, but its output may be attenuated.

2. If your sub has speaker-level inputs & outputs, use those for your desktop system (particularly helpful if your desktop amp only has stereo inputs & outputs, as the sub could then function as a crossover). Use the designated line-level LFE input as the connection from your receiver. Downside (if this works at all) is you'd have to change your crossover setting each time you switched sources.

I don't know if you've tried either of these or if they're workable at all, but I'm curious to find out.
 
#4 ·
1. If your sub has stereo line-level inputs, use one (usually the left channel) as LFE input from receiver. Use the right channel as the input from your PC - from what I've read, the right is still a valid mono input, but its output may be attenuated.
I tried this idea, and it didn't work.

It really is not an option for these two systems to be plugged into the same outlet.

I have since ordered 2 more RCA switches to see if any provide some relief. If not I may try using something like these:

https://www.amazon.com/gp/product/B000LP4RMG/ref=oh_aui_detailpage_o00_?ie=UTF8&psc=1

or

https://www.amazon.com/gp/product/B01L1NP7YI/ref=oh_aui_detailpage_o00_?ie=UTF8&psc=1
 
#3 ·
Sounds like a 60Hz hum issue. Try plugging in all the PC (and anything connected to the PC) and AVR (and anything connected to the AVR) into the same wall outlet.

As to connecting the sub, some sort of switcher should be in the mix, you don't want to systems talking to the sub at the same time (as would happen with different connection types).

A separate sub would be easier!
 
#5 ·
Which subwoofer do you own? Some subwoofers have dual inputs (LFE IN and LINE IN) so you can share the subwoofer with two systems without the need of a RCA splitter.
 
#7 · (Edited)
A few things to investigate:

1) As mentioned above make sure all components are plugged into the same CIRCUIT....even better, same Wall Socket.

2) Temporarily run a GROUND Wire between SW Chassis (or touching SHIELD of RCA INPUT) and METAL Case Screw for various components (incl. PC) to see if THAT makes the Hum go away. I have ALWAYS done this for those (mostly antique) components that use 2-Prong AC Plugs (like my '70's Marantz 250 Amp driving Antique ALTEC VOTT's....now SW's), to prevent LOUD buzzing sound whenever I change it's Input Plugs....

3) SOMETIMES, Hum will go away if you simply REVERSE the 2-Prong AC Plug on a Guilty Component [could be ANY component in your system]....try ONE at a Time....however, since one prong MAY be wider than the other to prevent incorrect polarity [a SAFETY OF LIFE feature], do NOT force or modify it. [One side is HOT, other side is NEUTRAL...that may or may not have better connection to Chassis Ground via a Capacitor and/or EMI Filter.] Of course, you can't [and SHOULDN'T] change 3-prong AC Plugs. [Unlikely to be a problem....unless something has a non-critical INTERNAL FAILURE.]

4) CATV Cable is oftentimes the SOURCE of Hum/Noise on the Ground System. If you have CATV, try temporarily disconnecting Coax to see if THAT is the Source of your problem. IF THAT is your problem, insert a CATV Coax Ground Loop Isolator:
https://www.amazon.com/TII-220-Ground-Isolator-applications/dp/B0070Q6URO [Must be for CABLE/CATV...avoid similar products for "VIDEO".]

5) Try inserting RCA Cable Ground Loop Isolator on PC [and then try AVR] SW OUTPUT Cable: [Mount Metal Can to Metal on Equipment that HAS a 3-Prong Plug to ensure it is Grounded properly.]
https://www.amazon.com/BOSS-Audio-B25N-Filter-Systems/dp/B000LP4RMG
https://www.amazon.com/XtremPro-Hi-end-Ground-Isolator-High-fidelity/dp/B01A56CMUO
 
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