Please, please help - Sub stopped working!


New member
Aug 10, 2019
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Ok - here's what I have: Onkyo TX-SR705, B&W 685 theatre package (685s front, 686s rear, HTM62 and ASW608). It's all brand new. For the last week I've been waiting for the 685s and the HTM62, but I just got them today. All the rest I've had for a week now, so was basically running a 2.1 system, with the 686s as the fronts and the ASW608 (which was working fine up until tonight).

Today, the rest of the kit arrived, so I moved the 686s to the rear and connected the 685s and the HTM62. I plugged the setup mic into the Onkyo, and when it came to putting a signal through the sub, nothing happened. At the end of setup, it said that no sub was detected.

I've double checked all the connections. The sub is powered by the outlet that's on the back of the Onkyo, using the 2-pin plug that came with the sub (rather than using the 3-pin plug and plugging it into the wall). It's connected to the subwoofer pre-out on the Onkyo using a Chord Crimson, to the Left line in on the sub.

I've tried the sub set to On, Auto and Standby - none of which makes any difference. The status light on the back just stays red, rather than going green when a signal is detected. There is no sound out of it whatsoever. I've tried manually setting the speaker config to "Subwoofer - Yes". Still nothing. As I've said, it was working fine for the last week.

One thing that has struck me is that the status light on the back seems to be more orange in colour all the time now - rather than switching between red for inactive and green for active. In fairness though, the orange thing might be just in my head - it changes a bit depending on what angle you look at it. It really doesn't seem as vivid a red as it was before though.

Anyway, I apologise for the length of this post, and I really appreciate you reading this far. If anybody can help me at all, please do - I really want to get this sorted out. I'd hate to think I'd been given a faulty sub.

Thank you so much,

Andrew Everard

New member
May 30, 2007
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The manual says

"Audio-visual processors incorporating an "automatic"
set up procedure may be "confused" by subwoofers
with an auto switch-on/sleep function. A potentially
damaging fault condition can arise. Subwoofers are
best left switched on and fully active during set up if
such a processor is used."

Could be too little signal, or signal of too short a duration, during set-up to 'wake up' the sub.

I'd suggest unplugging it, and reconnecting it direct to a wall socket. Then run the set-up again with the sub set to 'always on', and with the receiver's volume level set a bit higher.

You could also try using the 'right' input on the sub instead of the left one. Or try pinching the plug at the the receiver end of the sub cable between thumb and forefinger, so your fingers touch both the outer part of the plug and the inner pin. You should hear a buzz or hum from the sub, which will confirm that the sub is working, and the cable is OK.

It could, I guess, be an internal fuse blown, though this is unlikely, or a protection circuit triggered, though there's nothing in the manual to suggest a change in the the LED colour to show a fault condition.

Beyond that, a call to the supplying dealer may elicit some more information about this particular sub - sory not to have been more help, but specific information is hard to come by on the weekend before Christmas, so I've just given you what experience I have from fault-finding this kind of problem.

Hope this helps a bit, and you get things sorted.


Thank you so much Andrew. I have tried a few of the things you mentioned, but not all. I'll try everything again and let you know how I get on.

Thanks again!


Well, I tried all of the above, and nothing worked. I tried pinching the cable as you described and there was no sound at all from the sub. Does that confirm that there is something wrong?

I rang the dealer and he told me to bring it in for them to look at - so I brought it in today. He said if there was something wrong with it, he'd just replace it, and hopefully he could get one for me on Monday (they don't keep any B&W stuff in stock). Difficult time of year, but fingers crossed!

I never thought of testing the cable on its own, to rule that out. What would be the easiest way to test a Chord Crimson sub cable to check that it's ok?


Well, I got a new ASW608 from the dealer today. They told me they hadn't had time to investigate what was wrong with the old one, but the new one's connected and working beautifully - for now. I'll have to keep an eye on it, to make sure this one doesn't die too, but I presume the last one was just an anomaly.

Happy Christmas everyone!


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