Subwoofer starts playing randomly even with receiver off

Can anyone tell me what could make a powered sub start playing randomly even with the system off? It will just turn on and start making loud noise by itself even if the rest of the system is off. Sometimes it happens in the middle of the night (which wakes up everyone in the house).
Post edited by hifigal on

Comments

  • ViperZ
    ViperZ Posts: 2,046
    edited June 2012
    Your subwoofer is in stand-by mode, not OFF, there should be a switch in the back somewhere to physically turn it OFF. If the subwoofer 'turns on' in the middle of the night (i.e. it wakes up from stand-by), it means the amplifier in the subwoofer is broken and will require repair. Turn it off and unplug this subwoofer. It is unsafe to keep it in stand-by like that. There are cases like that with older JBL subs (i.e. PB12), which would do that exact thing, then they would catch fire.
    Panasonic PT-AE4000U projector for movies
    Carada 106" Precision Series (Classic Cinema White)
    Denon AVR-X3600H pre/pro
    Outlaw 770 7-channel amplifier
    B&W CDM1-SE fronts
    B&W CDM-CNT center
    B&W CDM1 rears on MoPADs
    JBL SP8CII in-ceiling height speakers
    Samsung DTB-H260F OTA HDTV tuner
    DUAL NHT SubTwo subwoofers
    Oppo BDP-93 Blu-Ray player
    Belkin PF60 Power Center
    Harmony 1100 RF remote with RF extender
    Sony XBR-X950G 55" 4K HDR Smart TV + PS3 in the living room
  • hifigal
    hifigal Posts: 2
    edited June 2012
    The sub is in auto mode so it should turn on when it senses a signal. It does do that, and it plays fine. However, it also randomly turns on and starts playing when there is no signal being sent by the amplifier. What is making it do this?
  • EndersShadow
    EndersShadow Posts: 17,236
    edited June 2012
    hifigal wrote: »
    The sub is in auto mode so it should turn on when it senses a signal. It does do that, and it plays fine. However, it also randomly turns on and starts playing when there is no signal being sent by the amplifier. What is making it do this?

    Perhaps its picking up signal from a ground loop in your system. Do you have cable or satelitte TV and is that cable close to the sub's RCA cable?
    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
  • jaritta
    jaritta Posts: 277
    edited June 2012
    I think I would try replacing the cable from the reciever to the sub first. If there is a loose connection or bad spot in the wire it can cause a ground loop hum which would bring the sub out of stand by mode into active mode when there is no signal from the reciever.

    I think I would replace the cable before I sent the reciever off for service.

    just my .02
    Harman kardon signature 2.1 amp
    Denon 3312
    Epson 8700ub
    Chief mount
    Screen Innovations Performance Series 110in
    Kef q 500 (RL)
    Kef q 200 (C)
    Kef q 800 (Rear RL)
    REL T7 (SUB)
    mx 450 remote
    Sonos-Amp, Connect, Play5
  • MADGSF
    MADGSF Posts: 603
    edited June 2012
    To expand on jaritta and EndersShadow's idea how about just disconnecting the cable from the sub, the one from the receiver that sends the signal. Then leave it like that for a few days with the sub in stand by mode and see if it comes on during the night. That might point you in the right direction.
    AVR: Elite VSX-21TXH
    Amplifier: B&K 7250 Series ii
    Misc: Velodyne SMS-1
    Mains: RTi-10
    Center: CSi-5
    Rear: Boston DSi460
    Sub: SVS PC-Ultra
    TV: Panasonic TC-P58V10
    DVD: Panasonic DMP-BD60K
  • I have same problem sub came on at 3 am and it was loud and was humming had to unplug it
  • gurot1
    gurot1 Posts: 511
    I had my computer speaker sub do that in the middle of the night. It turned out to be the wire connecting the computer to the sub that was the culprit in my case
    lsim705,lsim706c,lsif/x(4)+mc80(atmos)
    rti6,csi5,fxi5
  • VR3
    VR3 Posts: 24,688
    Skynet
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro