Subwoofer not working

SivaV

Novice Member
I have Whatmough synergy 5.1 speaker system, I had it for many years and all working great connected to Pioneer VSX LX-70 amplifier. I only recently noticed that my subwoofer was not working and I did following test but still no sound
  • Checked the power on sub-woofer, its picking up signal when amp is playing music and light goes to green when playing any movies from netflix or bluray
  • When playing any netflix movies, I can see 5.1 channel is active in THX cinema mode and LFE is active on amp but no sound in sub.
  • I tried tap test on sub but no sound on the sub.
  • I tried swapping subwoofer RCA cable from amp to sub and still no sound but lights is green.
  • I believe if light is green, fuse is all good so didn’t really check fuse near sub main power cable point.
  • I tried going into amp setup and manually tested each speaker for decible settings, I could hear from all 5 satellite speakers but when sub is hit there is no sound at all.
  • Amp settings are set to small (80Hz) for front speaker. Amp has got 50hz and 100hz settings as well, but since I felt signal from amp is generated I didn’t really tried changing these Hz settings.
  • Check all knob settings in sub for Phase, Crossover and Level settings to max but still not sound.

Any thoughts on what could have gone wrong? I had these Whatmough Synergy speakers for almost over 10 years now.

Is it worth buying a multimeter and test the sub to check if its blown or still working? I’m still not 100% if its sub issue or amp issue even though the amp seems to be sending signal that activates sub showing up green light.
 

Gasp3621

Distinguished Member
Seems the amp is working if green light comes, just need to get some sound with test tones. Have you connected the subwoofer cable to Pre Out subwoofer, not in the MultiCH sub out? See pic below yellow rounded one where it should be connected, not in the lower one. You tried another cable so that one is ruled off too. At the sub side the cable goes to Line In if i watched the correct sub amp picture, make sure you push the cable with little force each end so it goes to bottom. Phase knob to 0, crossover to max, level knob 12 clock is good starting point. All speaker sizes Small and subwoofer selected in the Pioneer menu. Power switch to On when you run the setup so it won´t go sleeping.



pioneer-vsx-lx70-71-channel-thx.jpg
 

SivaV

Novice Member
Seems the amp is working if green light comes, just need to get some sound with test tones. Have you connected the subwoofer cable to Pre Out subwoofer, not in the MultiCH sub out? See pic below yellow rounded one where it should be connected, not in the lower one. You tried another cable so that one is ruled off too. At the sub side the cable goes to Line In if i watched the correct sub amp picture, make sure you push the cable with little force each end so it goes to bottom. Phase knob to 0, crossover to max, level knob 12 clock is good starting point. All speaker sizes Small and subwoofer selected in the Pioneer menu. Power switch to On when you run the setup so it won´t go sleeping.



View attachment 1699335
Thanks for response. Yes you got the right picture of Pioneer LX-70, and I can confirm my sub RCA cable is connected to the right port as you circled in the yellow. I'm also attaching my sub picture with settings and RCA in, still no sound. All speaker sizes small.
 

Attachments

  • Subpic.png
    Subpic.png
    1.8 MB · Views: 11

gibbsy

Moderator
Taking the RCA out of the amp and then tapping it with the palm of your hand will make the sub give out sound. You'll have to get near to the unit. This could potentially show that the sub is working and the cable itself is not problematic.
 

SivaV

Novice Member
Taking the RCA out of the amp and then tapping it with the palm of your hand will make the sub give out sound. You'll have to get near to the unit. This could potentially show that the sub is working and the cable itself is not problematic.
Tried as you recommended but no luck, no sound at all from speaker!

Why would it stop working all of a sudden when I haven't touched any of the connection or settings on the amp or speakers? I don't know when exactly sub stopped working but only recently I have noticed that sub is not working, I might have cranked up volume in the past which might have blown the sub !

Is there any other way to test the sub?
 

gibbsy

Moderator
Mine did exactly the same. Turned out to be a failed relay, quickly and cheaply solved by a local hifi repair shop.
 

SivaV

Novice Member
Mine did exactly the same. Turned out to be a failed relay, quickly and cheaply solved by a local hifi repair shop.
Great, so looks like a sub speaker issue. I'm going to see if any of my friends have 5.1 AV receiver and do one last test to isolate its a sub issue then take it to the local hifi repairer.

Thanks and please do let me know if there is any other testing I could do using multimeter just like how its explained in this video
I don't have multimeter, but be a cheaper solution if I could isolate the issue.
 

The latest video from AVForums

Paramount + UK launch: Halo, Star Trek and Beavis, and all the latest 4K + Movie/TV News
Subscribe to our YouTube channel
Support AVForums with Patreon

Top Bottom