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Kube 2 Strange Problem.


Standard Member
Hi everyone,
I have the KEF 2005.3 speaker set, connected to a Sony Str-Dg820 amp. The Kube 2 subwoofer had an LED on the back that goes green when an input is going into it. However it only seems to go on if I set the amp to a particular volume, i.e if i have the volume set at 22 or lower, the sub goes into standby mode. Is this what they are supposed to do. I was watching the television, with a simple l/r input into the amp, and on the front of the amp it displayed that it was receiving front left front right and subwoofer. Would this be the reason why it needs a bit of volume or it doesnt send an input. If i turn the volume up the sub kicks in, then i decrease the volume below 20, the sub still stays working until about 15 mins, then it goes to standby? Strange.... My last Kube 2 went back for replacement because it wouldnt work at all. Could this be a problem with the Amp?

Any help would be great!

PS I have the sub cable going into the LEFT input on the sub.
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Standard Member
Hi Jim

It seems that you have an issue with a low trigger voltage from your processor. Most modern day subs have auto standby functions, so they turn on once they have any audio signal and then shut down after a given time period (looks like 15mins for the Kube-2), this helps to save power. So in your case it seems that the LFE output of your processor is a little below the voltage required to trigger your sub on. You will be glad to know that there are a couple of simple things to do in this situation.

1) Go into the menu of your AV processor and increase the level of the subwoofer by say 6dB. Then reduce the volume control on the rear if the Kube-2 so that the subs sounds to be at the same level as before. This way the voltage on your LFE connection will be higher and therefore it will always trigger the sub to turn on.
2) Use a phono Y cable, these have a single phono socket (female) and this then splits to two phono plugs (male). You then connect this between the LFE output and the two phono sockets on the rear of the Kube-2. You could get these from somewhere like Maplin or RS (if you want a cheap version) but QED do a good quality version and I am sure they will not be the only cable company doing such a cables

You could do both of the above as long as you do not start to clip the input of the sub, but you will be able to tell if you have as the sound on the sub will become distorted.

I have noticed this problem happen a few times recently particularly when using auto set-up sequences in like Audyssey where it does not get a suitable level for the sub channel. Not sure if any other people have found the same

Please let us know if this works


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Well-known Member
My Kube 1 did the same thing with my onkyo 605. I had to turn the gain on the amp up to 6db to get it to work correctly.

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