sub single wire or y wire

[newpolkman]

I have seen where you can either hook up sub to receiver with a single wire or a y wire. Is one better than the other or are they the same as far as sound quality? rex

[gatemplin]

On some subs using a Y splitter will defeat the crossover so you can avoid double filtering. I also have heard that the signal is 3dB stronger this way.

[Ceruleance]

Spec, if you answer this question please clarify why the signal is boosted 3 dB.

[PolkThug]

There is no SQ difference.

[Loud & Clear]

My CT series velodyne doesn't have an unfiltered LFE input on it, all it has is the left and right RCA's. Velodyne told me to use a y-splitter for better performance. So I did.

[Dr. Spec]

Originally posted by Ceruleance
Spec, if you answer this question please clarify why the signal is boosted 3 dB.

If you have a L and a R input, you are essentially sending the same voltage to each input when you use a Y splitter. Measure the voltage at each end of the Y splitter with a sine wave signal and you will see this is true.

The sub amp simply sums the voltage at the L and R inputs, so a doubling of the signal strength yields a 3 dB increase in sound pressure level.

If you don't believe it, try it, preferably with a sine wave signal. Run the sub with a single input and measure the SPL. Then connect the other half of the Y and measure again.

A Y splitter doesn't "add" any power or wattage on its own, obviously. It's just a friggin' piece of cable. You can accomplish the exact same effect by upping the AVR sub level 3 clicks.

The only reason to use a Y splitter is if the sub has a "sleepy" auto-on circuit.

[spasticpitbull]

LFE input if you got it, then set your crossover to your liking, tweek, crank er up and enjoy.

[walk]

If you use the LFE input, you don't need to touch the crossover dial, since it is by-passed - that's the point of the "unfiltered" LFE input. Your avr does the filtering/crossover...ing (hey I think I invented a new word!)

My sub (a CSW BassCube 8") is so "sleepy" that even with a Y-cable I have to boost the output on the avr by +9db to prevent it from going to sleep when the volume is at medium/low settings...

[Seaward]

what is a sleepy sub??

[scottvamp]

It is in reference to the auto "on" and "off". If a signal is weak it will shut off during low volume and queit scene's. But using a "y" will yeild a higher signal gain and keep the sub "awake" more.

[michael_w]

So is it better to just flick your sub to "on" instead of "auto on" and just use the single rca - no splitter? then you can just turn it off after your movie or whatever.

[michael_w]

So if it has some quiet scenes will the sub keep doing its stuff if it is set to auto on as long as there are explosions (or just loud scenes) every 15 - 30 mins or something?

[scottvamp]

It should.......

[michael_w]

lol ok thx :p

[walk]

If it's a huge problem you can switch it to "on", yes. Chances are you probably won't need to. Even with a "sleepy" sub - the timeout is set to 15 minutes, so it's not like it's constantly flicking on and off. We are talking some low volumes here, like watching TV late at night. In my case, even at very low volumes the sub stays on, all I had to do was boost the AVR's sub output +9db (and reduce the volume on the sub's control by roughly the same amount).