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Discussion Starter #1
That is someone posting a recommendation......Is this just another audio myth??



We are stricly talking about plate amps, which have a left and right RCA connections in. One of them is usually the LFE.
 

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Somewhere I read that you get a 6db? gain from doing it because you are sending the same signal twice so you get double the voltage. I may be way wrong though, I can't remember where I was reading this.
 

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Quote:
Originally Posted by Canadian_Dude /forum/post/14333103


Somewhere I read that you get a 6db? gain from doing it because you are sending the same signal twice so you get double the voltage.

Ridiculous.


Putting two 12v car batteries in parallel doesn't get you 24v!!!
 

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Quote:
Originally Posted by cavu /forum/post/14333147


Ridiculous.


Putting two 12v car batteries in parallel doesn't get you 24v!!!

No you won't get double the voltage, but you will double the amount of current available.

How that applies to a subwoofer cable I have no idea.
 

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Quote:
Originally Posted by bassface /forum/post/14333455


How that applies to a subwoofer cable I have no idea.

It doesn't. The AVR sub out is a low impedance voltage source. The subwoofer input is a bridging (high impedance) circuit.
 

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Quote:
Originally Posted by cavu /forum/post/14333472


It doesn't. The AVR sub out is a low impedance voltage source. The subwoofer input is a bridging (high impedance) circuit.

in other words no difference.
 

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Quote:
Originally Posted by aduljr /forum/post/14333482


in other words no difference.

Correct.
 

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I was given a recommendation from Manville from JL audio to add 2 separate lfe outputs to my F113 to get a boost in db.
 

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It was recommended to use a Y-cable on a AVA270 plate amp and it worked on both of mine, it was also tried with a pair of SUB250R plate amps and it worked with them as well. A Y-cable cost $1.19, it's cheap enough to buy and try it out. Connect it to the plate amp, and disconnect one input as the sub is playing. If you notice a drop in output from the sub, you'll know it works. It's that simple and easy.
 

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I thought I read in the subwoofer forum that the amp will simply add the two input signals together. The other way to increase this would be by adjusting the AVR's lfe output.
 

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Quote:
Originally Posted by JamesK8 /forum/post/14333675


I was given a recommendation from Manville from JL audio to add 2 separate lfe outputs to my F113 to get a boost in db.

Ridiculous.
 

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Quote:
Originally Posted by Uklit /forum/post/14333695


A Y-cable cost $1.19, it's cheap enough to buy and try it out.

It would be a waste of $1.19
 

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Quote:
Originally Posted by JamesK8 /forum/post/14333675


I was given a recommendation from Manville from JL audio to add 2 separate lfe outputs to my F113 to get a boost in db.

that might be to help the "auto-on" circuit ?
 

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Quote:
Originally Posted by otk /forum/post/14333741


that might be to help the "auto-on" circuit ?

You guys don't get it!


Combining two sub-outputs with multiple cables or a Y-connector from an AVR DOES NOT INCREASE THE AVAILABLE LEVEL!!!


If you need more level to trip the auto-on system, TURN UP THE LEVEL in the AVR.
 

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Wait, why don't you just turn up the volume knob on the amp a tad?


For auto on, you'll just need to turn the AVR up a tad. I always had issues with my roomate's sub turning off while listening to movies at night...but, as late as it was, I probably shouldn't have had the sub on anyway.
 

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on the other side of the coin: will splitting the signal with a Y-splitter from the LFE out of a reciever to go to 2 subs reduce the output level?
 

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Quote:
Originally Posted by soundemon /forum/post/14334057


on the other side of the coin: will splitting the signal with a Y-splitter from the LFE out of a reciever to go to 2 subs reduce the output level?

It shouldn't, but even if it did cause a voltage drop, you could just up the ouput level to compensate.
 

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Discussion Starter #18
How are the two inputs wired....I do not see how the amp would add the signals together to get a 6db increase.


I would usually just test this but Im 1000 miles away and Im curious. I will test next week using my LT/1300 amp.


btw, I 100% agree with those who say turning up the volume does the same thing!
 

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Quote:
Originally Posted by penngray /forum/post/14334706


How are the two inputs wired....I do not see how the amp would add the signals together to get a 6db increase.


I would usually just test this but Im 1000 miles away and Im curious. I will test next week using my LT/1300 amp.


btw, I 100% agree with those who say turning up the volume does the same thing!

If the input stage is set up as a mixer (L+R), then applying the same voltage so the two sub inputs will give an increase in effective voltage seen at the input to the amp stage. The voltage at each input should not be reduced by using the Y connector if the input impedance of each is, as it should be, orders of magnitude higher than the source impedance feeding it.
 

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In reality who cares? When you have your sub properly integrated with the speakers you have loads of extra capacity left in your subwoofer typically anyway. So how would this extra theoretical db mean anything except adjusting it out to integrate with your speakers.


Can someone educate me on this?
 
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