Need help with existing subwoofer connection (1 Viewer)

[chiefmoosepoop]

I purchased my current house in 2021 and am just getting around to making the home theater that was already here functional.

The theater is setup for 7.2 channel surround sound however the receiver is only for 5.1.

I currently have FL, C, FR, SL, and SR speakers working.

My issue is the subwoofer. I have two. Only one cable fed to where the receiver is. The cable is labeled “Subwoofer 1+2.” This makes me think the subwoofer cables going to each subwoofer are spliced together then the single cable is fed to the receiver. The cable used is 4x14 gauge wire. I have figured out that red/green is being used for positive and white/black for negative on all the other speakers.

The receiver only has a pre out for the subwoofer. I tried connecting it to an RCA adapter but that doesn’t seem to work.

My question is if I need to start from scratch and figure out how to rewire or if there is another solution?

 

[ManW_TheUncool]

Are the subwoofers what you bought yourself or actually came included w/ the house?

Those sub-labeled cables look like they may have been used for passive subs driven by some external amps perhaps, not the usual (coax w/ RCA termination) needed for most modern (active) subs fed by most AVR's sub (pre)out.

OR the previous passive subs may not be true LFE subwoofers at all and could possibly be (modestly) driven piggybacked off the previous AVR/amp's front L and R speaker outs perhaps, especially if the old front L and R speakers were only small bookshelf/satellite types w/ little-to-no meaningful bass output.

Anyway, if the subs are just passive subs (as I'm guessing), then no, you can't just use an RCA adapter for those wires to connect to the AVR's sub (pre)out... because that sub output signal isn't amplified at all (and passive subs don't have their own power source). Either way, you most likely should want to run new interconnect cabling between the AVR and powered/active sub(s) (that you might still need to buy, if that's not what you already have).

_Man_

 

[John Dirk]

As @ManW_TheUncool has noted, those appear to be line level cables [used for passive speaker connections] instead of the typical RCA connections you'd expect with powered subs. Are the subs accessible? A picture of the back panels might be helpful.

 

[JohnRice]

If the subs are installed in a wall or something like that, you can always buy a plate amp to power them. Of course, those types of "Subs" are often just bass modules, not really subs.

 

[chiefmoosepoop]

Are the subwoofers what you bought yourself or actually came included w/ the house?

Those sub-labeled cables look like they may have been used for passive subs driven by some external amps perhaps, not the usual (coax w/ RCA termination) needed for most modern (active) subs fed by most AVR's sub (pre)out.

OR the previous passive subs may not be true LFE subwoofers at all and could possibly be (modestly) driven piggybacked off the previous AVR/amp's front L and R speaker outs perhaps, especially if the old front L and R speakers were only small bookshelf/satellite types w/ little-to-no meaningful bass output.

Anyway, if the subs are just passive subs (as I'm guessing), then no, you can't just use an RCA adapter for those wires to connect to the AVR's sub (pre)out... because that sub output signal isn't amplified at all (and passive subs don't have their own power source). Either way, you most likely should want to run new interconnect cabling between the AVR and powered/active sub(s) (that you might still need to buy, if that's not what you already have).

_Man_

Thank you for your reply. The subs were already built into the wall

Are the subwoofers what you bought yourself or actually came included w/ the house?

Those sub-labeled cables look like they may have been used for passive subs driven by some external amps perhaps, not the usual (coax w/ RCA termination) needed for most modern (active) subs fed by most AVR's sub (pre)out.

OR the previous passive subs may not be true LFE subwoofers at all and could possibly be (modestly) driven piggybacked off the previous AVR/amp's front L and R speaker outs perhaps, especially if the old front L and R speakers were only small bookshelf/satellite types w/ little-to-no meaningful bass output.

Anyway, if the subs are just passive subs (as I'm guessing), then no, you can't just use an RCA adapter for those wires to connect to the AVR's sub (pre)out... because that sub output signal isn't amplified at all (and passive subs don't have their own power source). Either way, you most likely should want to run new interconnect cabling between the AVR and powered/active sub(s) (that you might still need to buy, if that's not what you already have).

_Man_

Thank you for the reply. The subwoofers are what came with the house. Seems to me like I need to figure out what kind of subwoofers these are. It also seems like the solution might be a little more complicated then I was anticipating. I’ll have to look into all the possible solutions you mentioned. Attached is the photo of my “theater.” Not much to it. The subwoofers are bottom left and right of the wrong wall. Each speaker has a speaker grill. Was hoping I wouldn’t have to pry them off.

 

[chiefmoosepoop]

As @ManW_TheUncool has noted, those appear to be line level cables [used for passive speaker connections] instead of the typical RCA connections you'd expect with powered subs. Are the subs accessible? A picture of the back panels might be helpful.

The subwoofers are in the wall with speaker grills. Need to figure out best way of getting access to the speakers without damaging anything. I almost feel as though the theater was built and originally used a different receiver then what is there now.

 

[chiefmoosepoop]

If the subs are installed in a wall or something like that, you can always buy a plate amp to power them. Of course, those types of "Subs" are often just bass modules, not really subs.

I’ll have to look into this option. I am very new to all this stuff so learning as I go. Thank you for your reply!

 

[chiefmoosepoop]

Are the subwoofers what you bought yourself or actually came included w/ the house?

Those sub-labeled cables look like they may have been used for passive subs driven by some external amps perhaps, not the usual (coax w/ RCA termination) needed for most modern (active) subs fed by most AVR's sub (pre)out.

OR the previous passive subs may not be true LFE subwoofers at all and could possibly be (modestly) driven piggybacked off the previous AVR/amp's front L and R speaker outs perhaps, especially if the old front L and R speakers were only small bookshelf/satellite types w/ little-to-no meaningful bass output.

Anyway, if the subs are just passive subs (as I'm guessing), then no, you can't just use an RCA adapter for those wires to connect to the AVR's sub (pre)out... because that sub output signal isn't amplified at all (and passive subs don't have their own power source). Either way, you most likely should want to run new interconnect cabling between the AVR and powered/active sub(s) (that you might still need to buy, if that's not what you already have).

_Man_

I just wanted to reply again and thank you for giving me the info. I’m the interim without spending a bunch of money I purchased a passive sub amp. Will see if that works for the time being. I see the quality might not be perfect with this option. I am starting to make sense of things

 

[JohnRice]

BTW, nothing has been joined together with that wiring. There are four wires, two for each sub. You'll have to be sure you have them figured out, so you know which are + and - to each sub.

 

[ManW_TheUncool]

IF you can, probably best to find out what model speakers and "subs" those are. Failing that, at least determine the size of the woofers on those subs might help some -- and take closer up pics of a front speaker and what seems to be matching (passive) sub.

With just that one low quality pic you provided, we can't tell at all what they are nor their quality, age/remaining useful lifespan, etc.

But what exactly is your goal for this HT space? What kind of expectations do you have? How loudly do you expect to push it, if at all? How does the system sound to you w/out those subs working? Do they sound very good to you for regular (non-bass heavy) music playback w/ no issues for instance?

_Man_

 

[chiefmoosepoop]

BTW, nothing has been joined together with that wiring. There are four wires, two for each sub. You'll have to be sure you have them figured out, so you know which are + and - to each sub.

I definitely have some testing to do. The 5 other speakers were wired so that the red/green were + and the white/black was -. It is definitely possible for the sub that they used one for each

 

[chiefmoosepoop]

IF you can, probably best to find out what model speakers and "subs" those are. Failing that, at least determine the size of the woofers on those subs might help some -- and take closer up pics of a front speaker and what seems to be matching (passive) sub.

With just that one low quality pic you provided, we can't tell at all what they are nor their quality, age/remaining useful lifespan, etc.

But what exactly is your goal for this HT space? What kind of expectations do you have? How loudly do you expect to push it, if at all? How does the system sound to you w/out those subs working? Do they sound very good to you for regular (non-bass heavy) music playback w/ no issues for instance?

_Man_

I need to figure out the best way to get the speaker grills off to take photos of the subs. If I took a closer photo now the camera would just focus on the grill. I assume they just pry off the wall

Right now the goal is just to have it running to use here and there. It sounds really good compared to tv with sound bar in the living room. Sounds fine without bass so if I can’t get the subs working I can live without them for now. Basically want to start using it before the wife decides to turn it into storage room or something else. Then down the road start upgrading things appropriately.

 

[ManW_TheUncool]

Basically want to start using it before the wife decides to turn it into storage room or something else. Then down the road start upgrading things appropriately.

I (and probably most of the rest of us) feel yah on that one, LOL.

_Man_

 

[Wayne A. Pflughaupt]

Basically want to start using it before the wife decides to turn it into storage room or something else.

Wife: Look honey, I got all my crafting supplies in one box!
Husband: I don't like it when you call our house a box.

The strange thing is that they ran 4-conductor wire everywhere and then tied the leads together like that. Thus, the subwoofer cable may not have separate connections for the two subwoofers – i.e., they might be daisy-chained.

To test, I’d connect either the red or green wire to your new amplifier's (+) speaker terminal. Then connect either the black or white wire. If you lucky, one of them (the black or white) will then get sound from one of the subwoofers.

If this ends up with sound from both subs, then they are daisy-chained. That’s not a problem, but you’d need to determine if the nominal impedance of the pair is suitable for the amplifier. This could be done with a common volt/ohm meter. Hopefully it’s not less than 4-ohms, as amps that can operate below 4 ohms are harder to find.

Regards,
Wayne A. Pflughaupt

 

[chiefmoosepoop]

Wife: Look honey, I got all my crafting supplies in one box!
Husband: I don't like it when you call our house a box.

The strange thing is that they ran 4-conductor wire everywhere and then tied the leads together like that. Thus, the subwoofer cable may not have separate connections for the two subwoofers – i.e., they might be daisy-chained.

To test, I’d connect either the red or green wire to your new amplifier's (+) speaker terminal. Then connect either the black or white wire. If you lucky, one of them (the black or white) will then get sound from one of the subwoofers.

If this ends up with sound from both subs, then they are daisy-chained. That’s not a problem, but you’d need to determine if the nominal impedance of the pair is suitable for the amplifier. This could be done with a common volt/ohm meter. Hopefully it’s not less than 4-ohms, as amps that can operate below 4 ohms are harder to find.

Regards,
Wayne A. Pflughaupt

Wayne,

Thank you for the detailed response. The amp I bought comes today and I’ll definitely be doing this. I’ll also look into the volt/ohm meter. With my luck they will be less then 4 ohms.

I appreciate your help.

Mitch