Connecting a powered sub with 2 inputs

[soundmonkey]

I recently purchased a soundbar and am considering adding a powered subwoofer that I can easily connect via RCA cables. The subwoofer I'm looking at also has the option of connecting via speaker wires, so I'm wondering if there's any reason I can't hook up the same powered sub to my 2-channel stereo receiver I currently have for listening to music. I obviously wouldn't want to listen to both sources through the same subwoofer at the same time, but in this scenario if I were to accidentally have my stereo receiver and soundbar sending out audio to the subwoofer at the same time would anything bad happen? I'm assuming nothing will short out because there isn't much if any juice in the RCA cable, but I'd value the advice of anyone with better knowledge of electronic internals than I've got. I've listed the equipment below.

Soundbar: Vizio S5430w-C2
Receiver: Onkyo TX-901 (legacy)
Subwoofer that I'm looking at: Polk Audio PSW10

 

[Adam]

Welcome to the forum!

You have another, safer option. Connect the soundbar and the Onkyo to the sub using the line level inputs. The PSW10 will use either the L or R line level input as the source, so you can hook the Onkyo to one of those and the soundbar to the other.

The Polk manual specifically states to not use both the line level and speaker level inputs. Maybe it wouldn't hurt anything, but I don't think that you need to risk it.

 

[soundmonkey]

Thanks for your reply but that's not an option as my legacy Onkyo receiver doesn't feature a line out.

 

[soundmonkey]

But yeah, that the manual says not to do it certainly isn't encouraging.

 

[Adam]

Thanks for your reply but that's not an option as my legacy Onkyo receiver doesn't feature a line out.

Sorry about that. My search led me to the TX-NR901, not the TX-901.

 

[soundmonkey]

No worries thanks for taking the time to do the legwork!

 

[soundmonkey]

I just looked at the manual online (this site won't let me link because I'm a newbie and it suspects me of being a spammer) and warning about not hooking up the speaker wire and RCA cable at the same time reads more like an admonition than a warning (no red triangles or anything indicating that it could damage equipment or start a fire).

On Page 7 Under the CONNECTING THE SUBWOOFER TO THE SYSTEM— HOOKUP OPTIONS
"Important Note: Use only one of these options. Never combine hookup option"


Note: Do not use the line or LFE input in this configuration.

On Page 10 under OPTION #2 (using speaker wire) it says:

Note: Do not use the line or LFE input in this configuration. (the manual is also for the PSW12, which has an LFE input)....

 

[soundmonkey]

I'm considering adding an AV receiver down the road. In that scenario I could either be safe and use an RCA switcher or connect one RCA cable from the soundbar and another from the receiver into the the left and right inputs on the subwoofer if I'm feeling brave (or stupid, depending on your perspective...) . But for now I like the idea of having separate systems (one of home theater and the other for music) sharing a subwoofer if I can do it safely.

 

[markw]

If you're looking for assurance that, in spite of the cautions issued by the manufacturers, you'll be fine using both inputs simultaneously, I'd be very surprised if anyone here will give you their blessings.

But, hey, you might get lucky here.

 

[Adam]

If you're looking for assurance that, in spite of the cautions issued by the manufacturers, you'll be fine using both inputs simultaneously, I'd be very surprised if anyone here will give you their blessings.

Funny...I was about to say, "I'd probably do it."

Honestly, I probably would, but I also know to only be upset at myself if I damage something. It should be totally fine if you are careful to never have the soundbar and receiver powered up at the same time. Even if you did, I'm not sure it would hurt anything.

Of course, the true Audioholics answer to your problem is - get two subs.

 

[TLS Guy]

If you do what you are suggesting you will blow up your receiver. When the sub is powered by the sound bar, there will be a signal at the speaker level inputs. It will be reduced in voltage. However if your receiver was on while the sub was being driven by the sound bar, then the receiver won't like it. Transistor amps do not like being powered backwards, so to speak, in any shape or form.

 

[Adam]

If you do what you are suggesting you will blow up your receiver.

No, it wouldn't. The OP isn't talking about running both at the same time, and even if that was done accidentally, it wouldn't "blow up" the receiver.

 

[TLS Guy]

No, it wouldn't. The OP isn't talking about running both at the same time, and even if that was done accidentally, it wouldn't "blow up" the receiver.

It very likely will blow it up. In the on state, solid state amps object to a signal being presented to speaker terminals. The signal is fed back to the high gain stages through the negative feedback circuit. Most amps do not like this situation.

 

[Adam]

Alright, soundmonkey, I guess it comes down to how risk averse you are. The manual says not to do it, and some here say not to do it. Personally, I'd be willing to role the dice on an 80's-era receiver and just try it out. I don't think that it'll hurt it, but that's my own personal belief and my risk posture. Contrary to TLS's statements, though, I don't think that you have to worry about flying shrapnel from an exploding receiver.

In my decades of using audio/video gear, I've done things that others here say simply can't be done - and guess what? They worked. So, I have my own experience base that leads me to say what I do, as do they.

 

[mike c]

i would have done so as well ... but TLS guy really put a monkey wrench in that plan.

if i understand correctly:
one source sends data to the line level input.
another source sends "data" to the speaker level inputs.

would the "data/signal/current" really jump from the line level to the speaker level and vice versa?

i mean, isn't this the same concept as one input to the L and one input to the R. we're not worried the L would climb up the R cable and back to the receiver.