Connecting two sub-outs of receiver with single sub

[Shashi Kumar]

Greeting guys,
This may sound like a technically poor question, but I need to close it out. I have a Yamaha receiver which has two sub-outs, but currently have only one sub-woofer. My question is - can I use a RCA y-connector to connect the two sub-outs of the receiver making it into one common sub-out and then connect this common to the sub-woofer? Will this be disastrous? Pardon me if this question is rather naive. Appreciate an answer though.

Best Regards,
Shashi Kumar

 

[ryanosaur]

There is no reason to do that. The one output should be sufficient and doubling the voltage delivered to a single input on your sub amp may be deleterious to the performance or health of your Sub.

 

[Shashi Kumar]

There is no reason to do that. The one output should be sufficient and doubling the voltage delivered to a single input on your sub amp may be deleterious to the performance or health of your Sub.

Thanks Ryanosaur. Wanted to check it out by actually doing it, but first wanted to be sure that it will not cause any damage-that would be a hard way to learn. So thought to better check it out on the forum.

 

[kini]

Actually Yamaha AVRs are known to have low voltage from the sub outs. It won't hurt anything as both sub outs are summed in the AVR anyway. It may help with the sub not going into standby at low volumes.

 

[ryanosaur]

Perhaps I misunderstand something here, but by taking both outputs from the AVR and combining them into one signal, are you not doubling the voltage that the Sub Amp will receive, thus potentially leading to clipping the Amp?
If anything, taking one single output and splitting it to two at the sub at the L/R input will still result in the Sub Amp receiving a normal signal voltage into each input, yet still result in safely increasing the response of any Music Sense feature without risk of overloading the Amp…
Whether necessary or not, this is how I’ve seen people connect their subs if not just using the single LFE signal pathway.

 

[lovinthehd]

@Shashi Kumar why do you want to do this? Personally have never even thought of doing this, but doubt it would cause any overt issues....not sure about the voltage doubling and even if it did you could just turn the gain on the sub down a bit to compensate I'd think.

 

[Shashi Kumar]

@Shashi Kumar why do you want to do this? Personally have never even thought of doing this, but doubt it would cause any overt issues....not sure about the voltage doubling and even if it did you could just turn the gain on the sub down a bit to compensate I'd think.

I am under the impression that one of the sub-outs is being wasted, and if I were to feed both the sub-outs from the AVR to the same sub, I would get more bang (or boom) for the buck.
Second, as Kini has mentioned in his post, I have a pro-sub 800 (Def Tech) which has the notorious habit of going to sleep in the middle of the movie , never to wake up, unless you try all kinds of stunts (repeatedly switching on and off of the sub, pulling out the lfe in at the sub and putting it back while everything is on and running) and are lucky enough to get the sub to wake up. The sub does not wake up on its own even when there is sufficient input going to the sub while it is slumbering. Maybe using the y-connector (provided the forum agrees that it is not harmful) is the best solution.
Believe it or not, I had to watch the last quarter of an hour of the movie Tenet again because the sub was snoring while there was huge action going on the screen.
hence the odd thinking.

 

[Shashi Kumar]

Actually Yamaha AVRs are known to have low voltage from the sub outs. It won't hurt anything as both sub outs are summed in the AVR anyway. It may help with the sub not going into standby at low volumes.

You are bang on target. The sub going into standby is a problem, and was hoping that this may cure the problem. Please refer response given to lovinthehd. Appreciate your response.

 

[lovinthehd]

I am under the impression that one of the sub-outs is being wasted, and if I were to feed both the sub-outs from the AVR to the same sub, I would get more bang (or boom) for the buck.
Second, as Kini has mentioned in his post, I have a pro-sub 800 (Def Tech) which has the notorious habit of going to sleep in the middle of the movie , never to wake up, unless you try all kinds of stunts (repeatedly switching on and off of the sub, pulling out the lfe in at the sub and putting it back while everything is on and running) and are lucky enough to get the sub to wake up. The sub does not wake up on its own even when there is sufficient input going to the sub while it is slumbering. Maybe using the y-connector (provided the forum agrees that it is not harmful) is the best solution.
Believe it or not, I had to watch the last quarter of an hour of the movie Tenet again because the sub was snoring while there was huge action going on the screen.
hence the odd thinking.

Well experiment with both the Y splitter (and your two sub pre-outs likely just have a splitter in the first place, not really wasting anything particularly) and two separate rca cords and let us know....the falling asleep thing is often addressed by using both the L/R inputs on the sub or by adjusting the avr's sub trim level and gain setting on the sub....but hopefully you can just get a better "sub" (hard to call that DT a true sub). What avr is it? There are some avrs with two sub pre-outs that are separately adjustable level/delay for the two different subs.....

 

[ctsv510]

If anything, taking one single output and splitting it to two at the sub at the L/R input will still result in the Sub Amp receiving a normal signal voltage into each input, yet still result in safely increasing the response of any Music Sense feature without risk of overloading the Amp…
Whether necessary or not, this is how I’ve seen people connect their subs if not just using the single LFE signal pathway.

^this is the way. One sub out to y splitter to two inputs on the sub.

 

[Speedskater]

You should never use a 'Y' / Wye splinter in reverse as a joiner!
Each output will see the other output as an almost short.

RAneNote 109 "Why Not Wye?"
Wye-connectors (or "Y"-connectors, if you prefer) should never have been created.

Anything that can be hooked-up wrong, will be. You-know-who said that, and she was right. A wye-connector used to split a signal into two lines is being used properly; a wye-connector used to mix two signals into one is being abused and may even damage the equipment involved.

Here is the rule: Outputs are low impedance and must only be connected to high impedance inputs -- never, never tie two outputs directly together -- never. If you do, then each output tries to drive the very low impedance of the other, forcing both outputs into current-limit and possible damage. As a minimum, severe signal loss results.

RANE Commercial - Knowledge Base

Rane Commercial

www.ranecommercial.com

 

[lovinthehd]

You should never use a 'Y' / Wye splinter in reverse as a joiner!
Each output will see the other output as an almost short.

RAneNote 109 "Why Not Wye?"
Wye-connectors (or "Y"-connectors, if you prefer) should never have been created.

Anything that can be hooked-up wrong, will be. You-know-who said that, and she was right. A wye-connector used to split a signal into two lines is being used properly; a wye-connector used to mix two signals into one is being abused and may even damage the equipment involved.

Here is the rule: Outputs are low impedance and must only be connected to high impedance inputs -- never, never tie two outputs directly together -- never. If you do, then each output tries to drive the very low impedance of the other, forcing both outputs into current-limit and possible damage. As a minimum, severe signal loss results.

RANE Commercial - Knowledge Base

Rane Commercial

www.ranecommercial.com

What about the OP's scenario of running one rca from each sub pre-out to each of the L/R inputs on a sub, what's the electrical outcome that way? Any concerns there?

 

[ryanosaur]

What about the OP's scenario of running one rca from each sub pre-out to each of the L/R inputs on a sub, what's the electrical outcome that way? Any concerns there?

I don't see that as being any different than using a y splitter from 1 out=>l/r in. it's going to be standard AVR voltage, no wacky issues with impedance or anything else to my (limited ) understanding.

 

[lovinthehd]

I don't see that as being any different than using a y splitter from 1 out=>l/r in. it's going to be standard AVR voltage, no wacky issues with impedance or anything else to my (limited ) understanding.

Yeah I'm thinking the same....was more wondering about the electrical difference, if any, in doing it this way, particularly in how the sub's amp would "see" it vs just the usual single rca connection from a single sub pre-out.

 

[ryanosaur]

Yeah I'm thinking the same....was more wondering about the electrical difference, if any, in doing it this way, particularly in how the sub's amp would "see" it vs just the usual single rca connection from a single sub pre-out.

My Outlaws have behaved pretty nicely since y-ing the inputs. I can't speak to the claim that it will boost output, but I have had significantly less issue with Music Sense tripping all over itself (which is why I did it ).
As far as two sub outs going to the L and R input? Other than the cost of a whole second cable vs a splitter, and the issue of having a second cable to run and perhaps hide... I just don't see the benefit. *shrugs

 

[Speedskater]

What about the OP's scenario of running one rca from each sub pre-out to each of the L/R inputs on a sub, what's the electrical outcome that way? Any concerns there?

That should be OK. 2 outputs, 2 cables, 2 inputs.

 

[lovinthehd]

My Outlaws have behaved pretty nicely since y-ing the inputs. I can't speak to the claim that it will boost output, but I have had significantly less issue with Music Sense tripping all over itself (which is why I did it ).
As far as two sub outs going to the L and R input? Other than the cost of a whole second cable vs a splitter, and the issue of having a second cable to run and perhaps hide... I just don't see the benefit. *shrugs

I've not had a sub where I needed to play around with the input/gain/connections to keep the auto on thing going when in use....but in this case the OP wanted the extra output not to go to waste and already has the second rca cord.....

 

[ryanosaur]

I've not had a sub where I needed to play around with the input/gain/connections to keep the auto on thing going when in use....but in this case the OP wanted the extra output not to go to waste and already has the second rca cord.....

Best/worst case scenario is he blows the DT. Best=gets real Sub. Worst=can't replace with anything but another.

 

[lovinthehd]

Best/worst case scenario is he blows the DT. Best=gets real Sub. Worst=can't replace with anything but another.

From Speedskater's response seems no reason to worry about using them the way the OP wants. Why would the DT blow (other than it's own usual problems)? .... That worst case could have a silver lining

 

[ryanosaur]

From Speedskater's response seems no reason to worry about using them the way the OP wants. Why would the DT blow (other than it's own usual problems)? .... That worst case could have a silver lining

I was referring back to combining the two outs into one in. Sorry not clear. As long as he doesn't join 2 out for one in, I agree he's fine.