Energy usage of speakers, monitors, computers

[x31forest]

I've started a site, http://www.thewattdb.com, where we can track energy usage of various devices in the household.
I'd like to ask for the help of anandtech users, that might have a Kill-A-Watt handy and a bit of free time, to populate the site with a couple of devices that they can measure.
I've measured my speakers, TVs, routers, wireless APs but I only have access to so many.

Thank for the help.
-Paul

 

[Harvey]

The power usage of any electronic device is supposed to be part of the specifications on the box and/or in the literature.

 

[x31forest]

What's listed on the specifications is usually the maximum energy, not the regular energy consumed. I found out that although I was not using my speakers (no sound was coming from them, but they were on) they were still using about 40W.

 

[zephyrprime]

Are those speakers hooked up to an amp or are they computer speakers?

 

[zephyrprime]

By the way your units are wrong. Don't say "watts per hour" because that's meaningless. Just say watts. Or, if you really want you can say "joules per hour"

 

[x31forest]

Computer speakers, they're the Logitech Z530, 5 speakers + subwoofer. It's probably the subwoofer that uses all this energy.

 

[Harvey]

Originally posted by: x31forest
What's listed on the specifications is usually the maximum energy, not the regular energy consumed. I found out that although I was not using my speakers (no sound was coming from them, but they were on) they were still using about 40W.

Did you mean a speaker-amplifier combination, such as computer/speaker setup?

Speakers, per se, don't use energy when they're not producing sound. A speaker is essentially a motor driven by the amplifier, and the power usage is by the amplifier driving it.

Amplifiers are rated for maximum power, but there is always use some idling current when there is no signal. The amount of power they consume is the idling current, plus the power they produce, plus the overhead, determined by the efficiency of the circuit. The efficiency of a typical class AB audio amp is around 30 - 40% or less. The efficiency of a switching amplifier (class D - class H) can be as high as 80% - 90%.

Amplifier ratings for low end commercial products are a joke. They often specify the absolute peak power the circuit can deliver at some unusably high level of distortion. A high quality audio amplifier should be specified at the maximum continuous power it can produce with an acceptably low level of distortion.

 

[Safeway]

Interesting idea, ***** website with 90% ads. Get a real interface, and I might help you.

 

[x31forest]

You think that there are too many ads ? I was trying to keep it low and have 2 only, one google ads and one specifically for the Kill-A-Watt from amazon. Which ad would you suggest I take down ?
What exactly is a real interface to you ? Is a search engine not a real interface ? Is the ability to add devices to your profile not a real interface ?

I'm asking for help here, so if you have something constructive I'll listen. If you feel this is crap, and you're entitled to have an opinion, then don't respond and it will go away by itself.

 

[x31forest]

Originally posted by: Harvey
Did you mean a speaker-amplifier combination, such as computer/speaker setup?

Speakers, per se, don't use energy when they're not producing sound. A speaker is essentially a motor driven by the amplifier, and the power usage is by the amplifier driving it.

Yes, of course, I meant to say a speaker sound system, and specifically the Logitech Z 530. I'm thinking it's the subwoofer that acts as an amplifier that's using all this power.

 

[NanoStuff]

Originally posted by: x31forest
Computer speakers, they're the Logitech Z530, 5 speakers + subwoofer. It's probably the subwoofer that uses all this energy.

I wouldn't be so sure. A number of high end speakers have tweeters in excess of 200W power handling, more than their woofers. I'd say it would be fairly evenly distributed.

 

[Harvey]

Originally posted by: NanoStuff

Originally posted by: x31forest
Computer speakers, they're the Logitech Z530, 5 speakers + subwoofer. It's probably the subwoofer that uses all this energy.

I wouldn't be so sure. A number of high end speakers have tweeters in excess of 200W power handling, more than their woofers. I'd say it would be fairly evenly distributed.

In almost any system, unless the upper range speakers are of some unimaginably inefficient, exotic technology, the woofer will require more power because it has to move more air, physically and because, typically, the signal amplitude in almost all music is greater in the bass region.

I couln't find a model Z 530's by Logitech, but I found model X 530 on their site:

Technical Specifications

• Total RMS power: 70 W RMS
• Satellites: 45 W RMS (2 x 7.4 W front, 15.5 W center, 2 x 7.4 W rear) Subwoofer: 25 W RMS Total peak power: 140 W
• Frequency response: 40 Hz - 20 kHz

This clearly shows what I was talking about regarding both the relative power used by the subwoofer and the rest of the system and the relationship between RMS and peak power specs.

FWIW, I design pro audio electronics.

 

[eelw]

tag so I can add some things later

 

[NanoStuff]

Originally posted by: Harvey
In almost any system, unless the upper range speakers are of some unimaginably inefficient, exotic technology, the woofer will require more power because it has to move more air, physically and because, typically, the signal amplitude in almost all music is greater in the bass region.

True indeed, but then there are 5 satellite speakers vs 1 subwoofer. Hard to call this one

 

[potato28]

I have a render problem on FF 2.0.0.5. I can see the site fine, but I have "
Notice: Undefined offset: 0 in /home/retele/public_html/electrodb/app/controllers/devices_controller.php on line 65" at the top.

 

[Rogodin2]

I use 3012kwhs per month in my buisness.

Rogo

 

[Skeeedunt]

That's actually kind of cool. I don't have a kill-a-watt, but I encourage others to contribute generously for my benefit.

 

[neutralizer]

Pretty nice site. I don't see ads (go adblock). I'd help, but I don't have a kill-a-watt either.