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Question: is it bad to leave subs ON


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The only reason I turn my subs off at night is because for some reason my amp things it needs to keep changing signals it's receives or doesn't receive causing the speakers to pop, including the sub. I was told it's because of a bug in the smart-mute function.

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Will have to pick up a few splitters to see if that makes the auto-detect feature work properly. Would be cool to get some extra oomph from them. Although they hit pretty hard as it is in their current home.

Maybe then I won't need 2 more when I move to the theater.........Nah...I'll "need" two more! Lol

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Most people reading this thread will already know this stuff, so this is for the ones who don't.


Nearly all subs have an Auto-On feature, and are activated/deactivated when they receive a sound signal through their cable, or stop receiving a signal.  It's not a feature of the receiver.  Some subs only show their Power light when they're active and switched on, but others keep their LEDs on whenever they're plugged in. With those ones, the LED gets brighter when the sub is active, then goes dimmer (but not off) when it turns off.


My smaller Yamaha subs have On-Off switches front and rear, and keep their LEDs lit at all times,  When I switch off the bedroom receiver, the subs stay live for 7 minutes, then turn off.  The LEDs get dimmer, but stay on.  Those subs have an Auto switch.


My Paradigm sub has no On-Off switch, which is sometimes inconvenient.  When I switch off the living room receiver, the Paradigm turns off in 17 minutes, and turns its LED off.  It has no Auto switch, just Level, Hi-Cut and Phase knobs.


All three subs have an Auto-Off feature.  The feature on the Yamaha subs can be switched off.  The feature on the Paradigm sub cannot be switched off.


This might be a clue for the OP.  Several years ago, I saw a premium sub cable (I forget the brand), so I bought it.  Didn't work out.  It caused the sub to hum slightly at all times, and it would not turn off, even when the receiver was turned off overnight.  The cable dealer was mystified when I told him the problem, but he did refund my money.  I re-connected the low-priced Electrohome sub cable I'd been using, and it's still working fine.


As for using a Y-splitter to connect your receiver to both of the sub's inputs, it will give you a 6 dB boost, but I wouldn't use it unless you need the extra power.  This is mentioned in the Paradigm users booklet.  I do it with my little 90 watt subs, but not with my larger 500 watt sub.

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Use a Y connector on the sub end.  It helps subs wake and go sleep.


These subs seem to need a splitter anyway.  It kind of works off a single RCA but if you just put a splitter in there, they get unleashed.  I don't understand what goes on in the circuitry for it to do this.  Even Speakerpower is like that, they claim a 6 db boost just by putting a splitter in-line.  




This is the science behind it:

There are two formulas used to find the db ratio between sound levels.

The first is used ONLY FOR POWER (watts): 10 . log (P2/P1). This formula is used when comparing Sound Intensity, measured in watts.

The second is used ONLY FOR VOLTAGES (and SPL levels): 20 . log (V2/V1). This formula is for voltage relationships and Sound Pressure Levels.

Using a Y adapter will add two correlated signals. When you sum two equal correlated audio signals (i.e., mono sources from sub output on the receiver/preamp), you will get twice the signal level (A1 + A2 = 2A1, since A1=A2).

Therefore , since V2 = 2 V1 and the log (2) = 0.30103, it follows

20 . log (2V1/V1) = 20 . log (2) = 6dB gain in voltage.

For power, it will be

10. log (2P1/P1) = 10 . log (2) = 3dB increase in power.

These are a few advantages (some real and some claimed) to using a Y adapter:

  • If you leave one of the RCA inputs open, dirt may get in there.
  • Using a Y adapter may add a few dbs to the subwoofers's output.
  • Some claim that the subwoofer works better at lower levels with the Y-cable.
  • The auto-off mode of some older subwoofers (e.g, Velodyne CH-12) may not come on at lower levels without the use of a Y-cable.
  • Some older subwoofers may actually need a Y cable because the left channel L may not default to mono signal.
  • Another benefit of using a Y-cable at the sub input jacks may be for reducing the amount of Radio Frequency (RF) and Electomagnetic (EM) interference, because you are not leaving the other input open and active. Subwoofers can be affected by annoying buzzes and hums.

Conclusion: Since Y adapters cost a few dollars and there is no significant risk involved, I would recommend using a Y adapter (2 male, 1 female) at the subwoofer's RCA input jacks. Make sure you use a good quality Y adapter that is shielded. Otherwise, you may hear hum and noises.  http://forum.blu-ray.com/showthread.php?t=95817

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I've had a pair in my media room on for 6 or 7 years straight. They were already 10-15 years old. So, I don't know if the previous owners did the same. No issues. Now, I have a newer sub that has been plugged in for 15 or so years and has auto on/off. I guess unless you ware worried about power surges from storms, etc. there isn't any reason to. I've been told it is actually better than turning them off and on constantly.

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