RMS and actual electrical power consumption

[Bluesmanuk]

I purchased a soundbar, where the manufacturers specs show 120W RMS and a power consumption of 25W.

I didn't think anything of it until somebody mentioned that I should buy a stock to power my home.

Their explanation was that if the soundbar is rated at 120W RMS for output, then the amount of electrical power required has to be the same.

Can anybody clarify as one of the reasons for the purchase was to buy something that was economical with regards to electricity consumption.

Thanks.

 

[makkem]

Hi
First what is the make and model of the soundbar.
Are you sure the manufacturer specifies the output power in RMS and not peak or peak music power.
With a 25W power consumption I would expect the soundbar to be in the region of 20W RMS.

 

[americanaudiophile]

You are rightly confused. Nothing is 100% efficient. You can't get more power out then you put in. The power rating of the sound bar is not measured in a standardized way so it might be able to put out that kind of power for 1milisecond. They can basically make the power spec up. If the amps inside are digital it might be 80 -90 % efficient so maybe at max volume maybe 20 watts as makkem says.

 

[Bluesmanuk]

Thanks for the replies.

It is a Philips HTL3120/12

I checked the user guide and it specified:

Amplifier
• Total output power: 120W RMS (+/- 0.5
dB, 30% THD) / 96W RMS (+/- 0.5 dB,
10% THD)
• Frequency response: 20 Hz-20 kHz /
±3 dB
• Signal-to-noise ratio: > 65 dB (CCIR) /
(A-weighted)
• Input sensitivity:
• AUX: 750 mV
• AUDIO-IN: 400 mV


Main unit
• Power supply: 110-240 V~, 50/60 Hz
• Power consumption: 25 W
• Standby power consumption: ≤ 0.5 W
• Speaker impedance: 8 ohm
• Speaker drivers: 4 x 3" woofer

I had read about the marketing blurbs with regards to PMPO but when I saw that Philips specified RMS, it have me wondering.

 

[makkem]

Well there is something not right about those figures,either the output power is not correct or the consumption.
I would find it surprising that a company like Phillips would incorrectly state RMS but quoting it at 30% THD is an eye opener as with that amount of distortion it would sound terrible.
No way to tell how they have arrived at the power consumption figure ,it is normally quoted as a maximum but they may have quoted the figure as an average at normal listening levels.If you measure the power consumption of an amplifier over a period of time the quiet times in the music will lower the average figure.
The only way to tell the actual consumption would be to use one of these.
http/

 

[ien2222]

My guess is that the 25w refers to the electronics part of the soundbar, such as the bluetooth receiver and pre amp portion, not what the amp draws.