Surprisingly high subwoofer standby power

Well, my speaker system (JBL SCS180.6) is not the newest but works fine. During use, the 150W subwoofer typically uses about 15W unless I really crank up the volume. There is a selection switch in the back for “On” or “Auto”. On “auto” it will go to standby if no signal is received and turn on automatically if needed (the current state is indicated by an LED (green=On, red=standby).

What surprised me was that while in standby that thing still uses about 9W of power! (as reported via tp-link HS300). Seems high but apparently normal for these kinds of devices. (I am tempted to put it on a switched outlet, triggered when the receiver is turned on but probably not worth the effort). I wonder if more recent subwoofers have a more pronounced standby advantage.

My 25 year old Paradigm PW 2200 subwoofer works similarly. Standby is around 6W. I have it on a KP115 right now and turn it off for stretches. I keep thinking about using IFFFT to turn it on when my AV receiver goes on an off when the AV receiver goes off, but haven’t yet.

Not subwoofers but - I have several different generations of Sonos Amps.
Connect:Amp uses about 5 w at idle (6 if you leave Wifi on).
The new “Amp” uses about 6-7w in standby.

So it feels like your subwoofer is right in line.

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Does your AVR have an outlet or two on the back to power other equipment? Some do, some don’t. If so they are often switched with the AV power and you could plug in your sub into that outlet to toggle it automagically.

Good thought. But sub is on the far side of room (30 feet) from the AV receiver/AV cabinet with two well trafficked walkways between the two. A shielded audio signal coax runs between the AV cabinet and the sub, through floor and wall. But it would be hard to fit an extension cord to that path, plus not to code.

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sounds like I should check my velodyne sub reading this… I also keep it on auto.
now I just need to pick up a hs300, or a single. not sure which…
I am new here, just got my sense and flex clamps setup the other day

My current receiver does not have power outlets, but a USB port that can be configured to be either (A) always on or (B) only on if the receiver is on. Using option B, I could wire the USB voltage into a relay that switches the subwoofer outlet. There are certainly turnkey options available (example). I wonder how many years I would have to use it until I recover the investment. :smiley:

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So I got a <$3 relay module with a 5V trigger, sacrificed some old cables (power and USB), put it all in a small box with some other parts I had laying around in the garage and now the subwoofer uses 0W when the receiver is off. What a difference:


I am sure you can tell from the graph what day it got installed (This is the subwoofer trace from the HS300). :smiley: Works well!.


I noticed this issue in my house when going through with a thermal camera. Subwoofer was mighty warm even though it was turned off. Took care of that by using a power strip with controlled outlets. Subwoofer only receives power when the receiver is on now.

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Ideally, there should be a software solution. For example a Sense rule that if the receiver kasa outlet goes above/below standby power, turn on/off the subwoofer outlet. (IFTTT would be way too slow). The solution needs to be local (i.e. not involve external servers or devices). Maybe the sense device itself could be programmed to do just that. (Not sure how that configuration would look like or how it could be implemented, just an idea for a Sense Lab feature :wink: )

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IMO, this sounds like a job for a home automation controller, not an energy monitor. I bet you could throw together an automation using hubitat (or HomeAssistant, but I don’t really know that platform) pretty quickly for this use.

True, I could e.g. set up a Google Home routine to turn on the receiver and subwoofer, but it won’t go on if somebody manually turns on the receiver to e.g. listen to radio. The subwoofer needs to go on whenever the receiver goes out of standby. Most of the time, the receiver turns on via HDMI CEC from the TV.

In a way, sense already is a “controller”, because the sense app allows us to switch any Kasa outlet. Obviously I have no idea about the sense system architecture and what is possible.

I personally don’t think Sense should have included the ability to control smartplugs in its UI, but that’s another topic for another day.

If you do end up deciding to get a Hubitat hub, it’s fairly straightforward to build this automation:

Thanks for the Hubitat information! That looks interesting. How much power does the hub use? (Of course it is 40+ times more expensive than what I did AND uses more power ;))

Curiously, the list of compatible devices does not include, “TP-link”, “Kasa”, or “Sense” (as far as I can tell but their community has some discussions).

No problem. Hubitat hub, based on some unofficial measurements, consumes less than 2W. It uses a USB power supply and doesn’t get warm to the touch.

The Kasa integration appears to be community-built. My experience is that many of the community apps are later integrated into the platform officially. It’s very much under active development.

FYI, the mobile app and web UI are both visually garbage. Don’t expect a user experience like Sense provides. It works great for automations you’re not interacting with on a regular basis, though.

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It’s overkill but I finally fixed this. I had an Eve Energy laying around from my first attempt at home power monitoring and accounting, so I replaced the KP115 I had the subwoofer powered through. Since my “Google TV” also does HomeKit and AirPlay2, I was able to do the simple automation below:

The TV Also turns the Yamaha AV amp on and off via HDMI-CEC. And the AppleTV and TiVo turn on and off the TV via HDMI-CEC. We’ll see how long this all happily works together, but so far, so good.