Is there any way to know how many watts you are using on your receiver?

[blued888]

Is there any way to know how many watts you are actually using on your receiver, at your own usual listening levels? I mean the power output to the speakers.

 

[malovich]

http://www.amazon.com/P3-International-P4400-Electricity-Monitor/dp/B00009MDBU/ref=pd_bbs_sr_1?ie=UTF8&s=electronics&qid=1227018871&sr=8-1

 

[blued888]

http://www.amazon.com/P3-International-P4400-Electricity-Monitor/dp/B00009MDBU/ref=pd_bbs_sr_1?ie=UTF8&s=electronics&qid=1227018871&sr=8-1

Power output to the speakers not power consumed by the receiver.

 

[Alex2507]

I'm sure there is a way to measure that but it's gonna cost money. I bet you could calculate it if you factored in the SPL of pink noise and the efficiency rating of your speaker.

How are you at quantum flux calculus?

 

[markw]

Radio Shack used to sell these. Maybe they still do, but no promises on that.

A quick google retrurned this item : http://cgi.ebay.com/REALISTIC-APM-500-AUDIO-POWER-METER-42-2107-SAVE$$$$$_W0QQitemZ260315891987QQcmdZViewItemQQimsxZ20081115?IMSfp=TL081115103010r20407

There are similar items out there if you are curious to google it yourself

 

[highfigh]

Is there any way to know how many watts you are actually using on your receiver, at your own usual listening levels? I mean the power output to the speakers.

Thinking of going totally photo-voltaic?

 

[blued888]

A quick google retrurned this item : http://cgi.ebay.com/REALISTIC-APM-500-AUDIO-POWER-METER-42-2107-SAVE$$$$$_W0QQitemZ260315891987QQcmdZViewItemQQimsxZ20081115?IMSfp=TL081115103010r20407

There are similar items out there if you are curious to google it yourself

Wow didn't know that kind of thing exists. I might just do the DIY circuit below just in case.

http://freecircuitdiagram.com/2008/09/13/audio-power-meter-show-audio-amplifier-actual-output-power/

Anybody handy with electronics know what wattage resistors I would need and what voltage capacitors?

Thanks markw!

 

[TLS Guy]

Wow didn't know that kind of thing exists. I might just do the DIY circuit below just in case.

http://freecircuitdiagram.com/2008/09/13/audio-power-meter-show-audio-amplifier-actual-output-power/

Anybody handy with electronics know what wattage resistors I would need and what voltage capacitors?

Thanks markw!

The resistors shunting the speaker should be 1/4 watt. That would be enough even for a hefty amp. An amp producing a peak voltage of 50 watts would have 1/8 watt power dissipation between R1 & R2. so 1/4 watt will be plenty. The other R1 and R2 1/8 or 1/4 watt should be fine.

The cap is across the power supply rail, which is 12 to 20 volts. So a 2.2mfd 25 volt should be fine.

 

[bandphan]

mac acutally makes a unit for the car that would work and is more than likely at total waste of money

 

[blued888]

The resistors shunting the speaker should be 1/4 watt. That would be enough even for a hefty amp. An amp producing a peak voltage of 50 watts would have 1/8 watt power dissipation between R1 & R2. so 1/4 watt will be plenty. The other R1 and R2 1/8 or 1/4 watt should be fine.

The cap is across the power supply rail, which is 12 to 20 volts. So a 2.2mfd 25 volt should be fine.

Other than this.... Would you happen to know what happens to the speaker output terminals at the back of the receiver? Does voltage increase as volume is increased?

 

[TLS Guy]

Other than this.... Would you happen to know what happens to the speaker output terminals at the back of the receiver? Does voltage increase as volume is increased?

Yes, it does. The power into a resistive load, is the square of the voltage divided by the resistance of the load. It can also be calculated from the square of the current multiplied by the resistance. Remember voltage drives and determines current. You can not expend power without a voltage driving current into a load.

However, this all falls down somewhat as speakers are inductive loads, and there is a phase angle between current and voltage. So there is true power, and apparent power. This unit would measure true power pretty closely I think. However the current for the apparent power has to be provided, and therefore an amp could still be driven into clipping, when a meter like this would indicate it was still in its linear zone.

 

[blued888]

Yes, it does. The power into a resistive load, is the square of the voltage divided by the resistance of the load. It can also be calculated from the square of the current multiplied by the resistance. Remember voltage drives and determines current. You can not expend power without a voltage driving current into a load.

However, this all falls down somewhat as speakers are inductive loads, and there is a phase angle between current and voltage. So there is true power, and apparent power. This unit would measure true power pretty closely I think. However the current for the apparent power has to be provided, and therefore an amp could still be driven into clipping, when a meter like this would indicate it was still in its linear zone.

Can I just do P=V^2/Impedance to get a somewhat rough estimate on power being used or would that totally be inaccurate?

 

[TLS Guy]

Can I just do P=V^2/Impedance to get a somewhat rough estimate on power being used or would that totally be inaccurate?

Unless you are measuring a sine wave it will be useless. Music is very dynamic, with huge instantaneous power changes. The ballistics of the meter would only allow you to make a rough estimate of the average power. For music, average power is only a fraction of peak instantaneous power, it is the latter that drives amps to clipping. Obviously if music is highly compressed in terms of dynamic range then average and peak move much closer together.

What are you trying to discover from all this any way?

 

[blued888]

What are you trying to discover from all this any way?

Thanks!

Just really curious as to how much power is actually used to drive the speakers. In my case, how much I normally use. Because I've heard some people say that 10w+ is already loud for an average person.

 

[TLS Guy]

Thanks!

Just really curious as to how much power is actually used to drive the speakers. In my case, how much I normally use. Because I've heard some people say that 10w+ is already loud for an average person.

10 watts average would be very loud. However you forget the db scale is log, therefore to stay clean playing a symphony at concert level really does require an amp of significant power, driving speakers of average sensitivity. If the average power was one watt, and that would actually be pretty loud, the amp needs a minimum of 100 watts at the ready, when the orchestra digs into the strings, the brass blazes, the tymps are pounded and the cymbals crash, but just for a brief period of time. I hate amps that clip right then!

 

[fmw]

The best way is to use a wattmeter. That's what I do. I have a commercial recording wattmeter that I picked up at an electronics repair shop that was going out of business. In my room with the home theater adjusted for normal listening levels (dialogue at the level I would hear if the actors were in the room with me) I get about 700 milliwatts continuous during musical segments and upwards of 20 watts on peaks (explosions etc.) into my main speakers. I do have a powered sub and that relieves the main speakers of some of the load, of course.

 

[blued888]

10 watts average would be very loud. However you forget the db scale is log, therefore to stay clean playing a symphony at concert level really does require an amp of significant power, driving speakers of average sensitivity. If the average power was one watt, and that would actually be pretty loud, the amp needs a minimum of 100 watts at the ready, when the orchestra digs into the strings, the brass blazes, the tymps are pounded and the cymbals crash, but just for a brief period of time. I hate amps that clip right then!

On those words, is having a 30wpc HK receiver not such a good thing? (Already made the purchase and am importing it from the US because it is $200+ cheaper than here. I got the basic because I simply need 5.1, no need for other features.)

I just feel sort of wary of HK's way of rating things. I believe I never entered clipping region on my previous entry-level Yamaha which was rated at 75wpc. But with that in mind, what is usually heard when an amp clips?

I am also used to seeing 75wpc as a bare minimum when looking at receivers from Onkyo, Denon, Yamaha.

Does this mean the HK I purchased has a hard upper limit of 30wpc for peaks and will clip beyond that?

 

[TLS Guy]

On those words, is having a 30wpc HK receiver not such a good thing? (Already made the purchase and am importing it from the US because it is $200+ cheaper than here. I got the basic because I simply need 5.1, no need for other features.)

I just feel sort of wary of HK's way of rating things. I believe I never entered clipping region on my previous entry-level Yamaha which was rated at 75wpc. But with that in mind, what is usually heard when an amp clips?

I am also used to seeing 75wpc as a bare minimum when looking at receivers from Onkyo, Denon, Yamaha.

Does this mean the HK I purchased has a hard upper limit of 30wpc for peaks and will clip beyond that?

It all depends on the sensitivity of your speakers, the type of program you listen to and how loud you like to play it. If you have speakers 6db more sensitive than the average then you have the equivalent of a 120 watt per channel amp driving speakers of the usual 89db 1 watt 1 meter sensitivity.

If you listen to a lot of highly compressed pop and rock you also will likely be OK. If you like to listen below concert level, you will also be OK. If you have speakers of average or below average sensitivity, and want to listen to content with high dynamic range at concert level, then you probably won't have enough power.

Clipping is a sudden very harsh edge to the sound on the peaks, in the most severe form even sounds like a rough crackle. It is not a good idea to frequently clip amps, it heats up the output devices and causes premature failure.

And yes, your amp will progressively go into clipping as you exceed its rated power.

One other point, on an amp of that price, if your speakers are four ohm, or are "nominal" eight ohm speakers that frequently are actually four ohm speakers below 400 Hz, that receiver will almost certainly deliver only 15 watts per channel. All I can tall you is that that amp delivers 30 watts per channel into resistive 8 ohm loads, all channels driven, and 40 watts per channel stereo into resistive 8 ohm loads. Into real world speakers that have impedance dips and phase angles between voltage and current, then the power it will actually deliver is is likely to be significantly less. However HK do not specify power into resistive loads, below 8 ohms, and you have to assume it is because they don't want you to know.

So whether you get into clipping or not depends on a lot of variables.

 

[blued888]

It all depends on the sensitivity of your speakers, the type of program you listen to and how loud you like to play it. If you have speakers 6db more sensitive than the average then you have the equivalent of a 120 watt per channel amp driving speakers of the usual 89db 1 watt 1 meter sensitivity.

If you listen to a lot of highly compressed pop and rock you also will likely be OK. If you like to listen below concert level, you will also be OK. If you have speakers of average or below average sensitivity, and want to listen to content with high dynamic range at concert level, then you probably won't have enough power.

Clipping is a sudden very harsh edge to the sound on the peaks, in the most severe form even sounds like a rough crackle. It is not a good idea to frequently clip amps, it heats up the output devices and causes premature failure.

And yes, your amp will progressively go into clipping as you exceed its rated power.

One other point, on an amp of that price, if your speakers are four ohm, or are "nominal" eight ohm speakers that frequently are actually four ohm speakers below 400 Hz, that receiver will almost certainly deliver only 15 watts per channel. All I can tall you is that that amp delivers 30 watts per channel into resistive 8 ohm loads, all channels driven, and 40 watts per channel stereo into resistive 8 ohm loads. Into real world speakers that have impedance dips and phase angles between voltage and current, then the power it will actually deliver is is likely to be significantly less. However HK do not specify power into resistive loads, below 8 ohms, and you have to assume it is because they don't want you to know.

So whether you get into clipping or not depends on a lot of variables.

I plan to use the HK with Yamaha satellites rated at 6-ohm with a sensitivity of 87dB. This is for a secondary setup only. Link

Main setup would be a Yamaha RX-V663 paired with an Infinity Primus speaker set. I will of course also try pairing the Infinity set with the HK and see how it sounds.

I rarely listen to music, 95% of the use will be for home theater. Is music considered more dynamic than home theater sounds?

I never listen at concert/reference levels due to possible neighbor complaints.

 

[TLS Guy]

I plan to use the HK with Yamaha satellites rated at 6-ohm with a sensitivity of 87dB. This is for a secondary setup only. Link

Main setup would be a Yamaha RX-V663 paired with an Infinity Primus speaker set. I will of course also try pairing the Infinity set with the HK and see how it sounds.

I rarely listen to music, 95% of the use will be for home theater. Is music considered more dynamic than home theater sounds?

I never listen at concert/reference levels due to possible neighbor complaints.

If this is a secondary system and you don't listen at high level you will be fine. Movies actually have a high dynamic range,at least many do. It is the pop rock scene that has such high levels of dynamic compression.

I think your quarter has run out in the meter now.