Actual Subwoofer power consumption

[docferdie]

Does anyone know how much power a subwoofer is really supposed to draw at the wall compared to how it is rated? I have a Klipsch KA-1000-THX that is supposed to be 1500W AC but in use only pulls 30W from the power source. Is this normal or should I get this replaced?

 

[Adam]

Does anyone know how much power a subwoofer is really supposed to draw at the wall compared to how it is rated? I have a Klipsch KA-1000-THX that is supposed to be 1500W AC but in use only pulls 30W from the power source. Is this normal or should I get this replaced?

Sounds okay to me. With speakers, you have to use ten times the power in order to double the volume. As a reference, most of the time with speakers, people are sending less than one Watt to them on a continuous basis.

Crank it up, and you should see an obvious change in the power draw.

 

[WmAx]

Sounds okay to me. With speakers, you have to use ten times the power in order to double the volume. As a reference, most of the time with speakers, people are sending less than one Watt to them on a continuous basis.

Crank it up, and you should see an obvious change in the power draw.

Actually, about 4x power increases the actual amplitude by 2x. 6dB is technically 2x amplitude. 10dB refers to a very old perceptual study and it's conclusions regarding what people perceive as 2x, not actual 2x. Though, I need to find that paper and review it (mtrycrafts?), as 6dB has always sounded about double the amplitude to me, though this is under sighted conditions, thus subject to bias.

-Chris

 

[Adam]

Actually, about 4x power increases the actual amplitude by 2x. 6dB is technically 2x amplitude. 10dB refers to a very old perceptual study and it's conclusions regarding what people perceive as 2x, not actual 2x. Though, I need to find that paper and review it (mtrycrafts?), as 6dB has always sounded about double the amplitude to me, though this is under sighted conditions, thus subject to bias.

-Chris

Chris, thanks. With that assumption, would you still agree that docferdie's power draw sounds reasonable for normal listening levels?

 

[WmAx]

Chris, thanks. With that assumption, would you still agree that docferdie's power draw sounds reasonable for normal listening levels?

How is he measuring? Under what conditions? That is a reasonable average power draw. Peaks should draw far more power.

-Chris

 

[Adam]

How is he measuring? Under what conditions? That is a reasonable average power draw. Peaks should draw far more power.

-Chris

We'll have to wait for docferdie to log back on and let us know.

 

[docferdie]

Thanks for the replies. I have a Denon 4806CI and the sub plugged into an APC s15 which should only be able to put out 900 watts. Reference level was done by auto-setup and I had the denon at -20dB. I used 50 cents in the club for testing. I tried minimum and maximum levels on the sub with the thx crossover bypassed and tried varying the crossover as well. The sub would definitely get louder and I would get some furniture shaking/wall creaking but the APC would always report just a 30W power draw. Pretty much the only way to change anything with the Klipsch amp is to turn it of then I would see power consumption drop on the APC by 30W (the Denon would pull about 100W of power when I turn it on but its power consumption doesn't vary either whether or not there is any sound coming from my speakers or whether I change the volume--the Denon is supposed to draw 10.6 amps or about 1300 watts of juice. I have a computer plugged into the same power supply that actually has variable power draw depending on whether it is idle or running 3d games.)

 

[Adam]

The APC is likely not capturing any of the transient spikes, but rather is showing an overall average power draw. I'll bet you that you can get the Denon power draw to go up over 100W continuous - but you will have to crank it. I think that receivers handle the transient spikes (cymbal crashes, short loud noises) by discharging their capacitors, so you wouldn't see much happening on your APC. I see the same thing on my Belkin power console with my Pioneer. No real change in power unless I really turn it up.

Either way, if you think that it sounds good and is loud, then don't be disappointed that it's not jacking up your power bill!

 

[mtrycrafts]

Actually, about 4x power increases the actual amplitude by 2x. 6dB is technically 2x amplitude. 10dB refers to a very old perceptual study and it's conclusions regarding what people perceive as 2x, not actual 2x. Though, I need to find that paper and review it (mtrycrafts?), as 6dB has always sounded about double the amplitude to me, though this is under sighted conditions, thus subject to bias.

-Chris

F.Alton Everest's book mentions both values, 6 dB in some studies and 10dB in others, no specific citation. He uses 10dB based on many experiments and hundreds of subjects, again, no list of those citations.

Don and Carolyn Davis' book also said the same, or rather they use 10 dB for 2x perception of loudness.

 

[mtrycrafts]

Does anyone know how much power a subwoofer is really supposed to draw at the wall compared to how it is rated? I have a Klipsch KA-1000-THX that is supposed to be 1500W AC but in use only pulls 30W from the power source. Is this normal or should I get this replaced?

That may be its capability at max output, not normal use