Measuring power output of a speaker amp to the speaker?

[Chrispy]

Klipch R51-M

+
Kanto sub8

Klipsch spec'd sensitivity is overstated by 4-5dB compared to what most others do (Klipsch uses an "in-room" equivalent spec).

 

[antcollinet]

You mean I'm getting that much sound from a 1/3 of a watt? The SPL meter said 60dB at 1 meter. I just used an app for me phone so it could be totally wrong. This means that 25 watts would be WAY more than most people would ever need.

Not necessarily. You need to go 10x in power to roughly double the percieved volume.

So 1/3W for your normal fairly low volume. 3W for double that. 30W to double it again (We are talking percieved volume, not watts or spl here)

So your 25W is less than 4 times louder (percieved) than your 1/3 watt.

 

[Mario Soldier]

I read the whole thread but didnt understand much.

When i herar music very loud i can measure 13 Volts at the speaker inputs ans about 2,5 ampre current (peak) . What does this mean?
I try to find out how strong my amp has to be.

The Amp i used is rated 250/500 8/4 Ohms and the clipping diode sometimes lighted up.

How can this be if i only use 32,5 WAtt at 5.2 Ohms .

Or would it be easier to measure the power input of the amp (class D)


Regards

 

[antcollinet]

I read the whole thread but didnt understand much.

When i herar music very loud i can measure 13 Volts at the speaker inputs ans about 2,5 ampre current (peak) . What does this mean?
I try to find out how strong my amp has to be.

The Amp i used is rated 250/500 8/4 Ohms and the clipping diode sometimes lighted up.

How can this be if i only use 32,5 WAtt at 5.2 Ohms .

Or would it be easier to measure the power input of the amp (class D)


Regards

Lets ignore phase for the time being (if there is a phase shift between current and voltage, then your power is not apparent I times apparent V). Speakers are complex impdeance loads so measuring real power is difficult unless you have a true power meter.

But then:
1 - how are you measuring peak current? If using a meter type device it is very unlikely to be capturing the real transient peaks.

2 - How are you measuring the voltage? A simple meter may not be giving an accurate RMS reading for a music waveform.

3 - But let's take your 13 volts RMS/Average at face value and assuming 6ohm (nominal speakers) that is going to be in the order of 30W (again ignoring phase effects). Let's say. your music has dynamics of up to 15 dB - so that would be transient peaks in power of 30x2^5 = 960W (Every 3dB is a doubling in power).

 

[solderdude]

I read the whole thread but didnt understand much.

When i herar music very loud i can measure 13 Volts at the speaker inputs ans about 2,5 ampre current (peak) . What does this mean?
I try to find out how strong my amp has to be.

The Amp i used is rated 250/500 8/4 Ohms and the clipping diode sometimes lighted up.

How can this be if i only use 32,5 WAtt at 5.2 Ohms .

Or would it be easier to measure the power input of the amp (class D)


Regards

You probably measured 'average' values. Your meter is simply not 'fast enough'.
To measure the power you will need something like an oscilloscope with 'memory' function and can calculate currents from that or use a current clamp with the oscilloscope when using music.

When the clipping indicator lights you will have had peaks close to the amp rated max. values.

 

[Mario Soldier]

Ok understand, measured the voltage with an cheap Mutimeter , and the current with an clamp.

It is this amp that clips if i only using one .https://www.tools4music.de/index.php?eID=dumpFile&t=f&f=4124&token=88ed6ee4e8f77ea00c3c62c5ba4422b0734429a5

Ist has an Pascal s pro 2 Module. If a use 2 in BTL Mode it seems i am far away of clipping.

And i measure about the same at the speaker inputs 10-13 Volts and 2-3 Amp when i am using two icepower 1200 As1 Modules rated 600/1200 8/4 Ohms.


What i also can measure is the power (max Wattage) the amp soaks of the 240 Volt Line.i will try.


But i think it is not a good idea using a purifi ET400 Module??? it is weaker :And iam not sure if i can hear clipping, my Purifi amps have no clipping indicator.

Ok playyed music with more bass this time i measured 25 Volt max and 5 Amps max. probaly only 4 Ampere current.And for very very shot time i saw 7 Amps on the clap (possible the lowest impedance of my speaker 3,7 Ohm)

And the wattage Meter says 200 Watt in put maximum.

So i should stay with these amps and not use much weaker modules?

And forget to say the 25 Volt and 5 Amp are for one module with one speaker the 200 Watt maxmium input are for both modules.

Ist seems it is relative smiliar 100-125 Watt max output for one module and 100 Watt input.
Of course the output can not be higher than the input the efficience of this module is 85% probably more.


Thanks.

 

[solderdude]

As long as the sound quality does not get 'worse' at the highest levels you want to listen to there is no need to go for a more powerful amp.
Also, as hearing is close to logarithmic to go noticeable louder you need to at least triple or quadruple the amp output rating and keep the recommended power rating of the speaker manufacturer in mind.

Measuring something is only useful when done right (correct signals, measurement gear and protocols) otherwise it is somewhat indicative at best.

 

[Mario Soldier]

As long as the sound quality does not get 'worse' at the highest levels you want to listen to there is no need to go for a more powerful amp.
Also, as hearing is close to logarithmic to go noticeable louder you need to at least triple or quadruple the amp output rating and keep the recommended power rating of the speaker manufacturer in mind.

Measuring something is only useful when done right (correct signals, measurement gear and protocols) otherwise it is somewhat indicative at best.

The Speakers are Klipsch RF7 MK3 rated 250 Watt RMS and 1000 Peak KLipsch says ist is an 8 ohm but most people say it is 4. Also KLipsch says it has an efficiency of 99db 1W/1m But it is more 94 db

Yes of course but my Question was not the need for a more Powerful Amp, the 1200 As1 and Pascal Spro2 BTL hava more than enogh Power.The Question for me was can i go with a less Powerful Amp but newer an possibly better , the Pascal S pro 2 is 10 Yyears old.The icepower 5. The Question was going with an NCx 500.

But iam alo not sure if i would hearing some difference.

I hear music in streo very loud and only with the front boxes. But i also watsch movies, not so loud for the movies i know an amp with much less power is no Problem.
But is ist worth the change i also dont know.All other channels even the Atmos use Purifi modules

Understand but my idea was buying an amp with much better measurement (on the other 11 channels is use purifi modules).
But for the front i use Icepower 1200 As1 x2 or Pascal S Pro 2 2x in BTL Mode .

The Question for me was probably using also an Purifi ET400 or NCx500 or Hypex NIlai Modules couse they are probably much better than the icepower/Pascal.


But i would lose a lot of Power the Icepower are rated 600/1200 and are clean till 500/1000 Watt 8/4ohm , for the Pascal Modules i can not find measurement in BTL Mode but they are rated 900/1000 Watt 8/4ohm.

The lowest Speaker imedance is a dip with 3,8 OHm.

Then i had the idea of bridging the Purifi ET400,Ncx500 or Nilais. But Purifi says "no bridging (But ist is done by VTV and Nad) , a bridged NCx500 i can not found and i can not buy the module.
Than the idea with the Nilai.
But the Nilai SMPS is not Powerful enough Hypex says it has only 500 Watt , sobridging twao NIlai Modules gives only 500 Watt (But on their webside Hypex says two Nilai BTL with one power supply is 800 Watt).

Not Sure an Dual MOna amp can be bridged 2 Nilai Modules with 2 Power supplys.

So iam totaly unsure what to do, couse i dont know if the Power is enough, so i tried to find out.....


Are my measurement not good enough to say I can also go with an NCx500 Stereo or Dual MOna Amp instead of the Pascal/Icepower????


I have no idea so i think i have to wait to the release of the new Purifi BTL Module.


Thanks.

 

[solderdude]

The Question for me was probably using also an Purifi ET400 or NCx500 or Hypex NIlai Modules couse they are probably much better than the icepower/Pascal.

Better specs than the current amps will not translate to better sound quality. It will just be measurably better on paper and manufacturers like that want to push the limits of technical performance and sell more modules.

Are my measurement not good enough to say I can also go with an NCx500 Stereo or Dual MOna Amp instead of the Pascal/Icepower????

Your measurements say nothing really. To see if you are clipping anything you need better suited test equipment.

 

[Mario Soldier]

Better specs than the current amps will not translate to better sound quality. It will just be measurably better on paper and manufacturers like that want to push the limits of technical performance and sell more modules.



Your measurements say nothing really. To see if you are clipping anything you need better suited test equipment.

Yes thats the question, will i hear any difference?Some people her in Forum say the Icepower modules also the pascal have a bad frequency response amd have much more distortion in high frequencies than the Purifi/hypex Modules.The Sinad is worser and so on.

But will i hear that?

I have many Module from Icepower 300As1,700 As1 and As2 1200As1 and As2 125ASX BTL ,some Pascal Modules and here no differnce to the Purifi ET400 or Hypex NC400 .

Purifi and Hypex was much more expensive of course.

It seems for me ther is only a difference in Power.

The Rest of my Equipment is probably not good enough to hear a difference.So the amp is not the bottle neck,perhaps the speakers are.

Some here(everybody?) are sure,they hear a difference beetween the icepower and Hypex/Purifi Modules.

They hear the distortion of the high frequencies the icepower modules does.

With all of the modules in idle there comes nothing out of the speakers they are all quite.


But couse of so many people say icepower is bad couse of thi and this bla bla , i think i have bad ears and can probably not hear it.

 

[RayDunzl]

I couldn't get over .5 volt from the speaker posts and it was getting LOUD. I'm sure that reading is wrong.

 

[Mario Soldier]

Lets ignore phase for the time being (if there is a phase shift between current and voltage, then your power is not apparent I times apparent V). Speakers are complex impdeance loads so measuring real power is difficult unless you have a true power meter.

But then:
1 - how are you measuring peak current? If using a meter type device it is very unlikely to be capturing the real transient peaks.

2 - How are you measuring the voltage? A simple meter may not be giving an accurate RMS reading for a music waveform.

3 - But let's take your 13 volts RMS/Average at face value and assuming 6ohm (nominal speakers) that is going to be in the order of 30W (again ignoring phase effects). Let's say. your music has dynamics of up to 15 dB - so that would be transient peaks in power of 30x2^5 = 960W (Every 3dB is a doubling in power).

Thats probaly right.
I tried the same (couse if have no other equimpent and dont know what to buy).
This time i used one hypex UCD400 Oem with one smps 400 and clipping indicator, I measure 26 Volts max and 4,2 Ampre max at the speakers.
And it pulls out of the wall 130 max Watt (230 Volt) , the power consuption device says when its clipping, of course the clipping indicator is not continius on).

My music has very low dynamics (dubble bass metal) ,not more than 5 db dynamics and of course ist clipps only in the hard parts.

In my opinion the measurement at the speakers fits the max watt ouput on the wall.

The modul is rated 400 Watt at 4 ohms.

But when you look here (6 or 6.1) the modul is clipping at about 130 Watt output 4 Ohm 1 kh/z , and i think at 60 HZ ist is clipping erlier.

https://www.hypex.nl/media/55/d0/6d/1645888843/UcD400_OEM_R13.pdf

My measurement can be wrong but is dont think the power consuption device is lieing.

 

[solderdude]

The amp modules will clip at the specified numbers by the manufacturer.
To measure that you need suited measurement gear and loads.
Speakers and music simply are not suited as test signals unless you have specialized gear (storage oscilloscope for instance)
Drawn power from mains will tell you nothing as peak powers are drawn from reservoir caps inside the amp and are not drawn directly from mains.

 

[Mario Soldier]

The amp modules will clip at the specified numbers by the manufacturer.
To measure that you need suited measurement gear and loads.
Drawn power from mains will tell you nothing as peak powers are drawn from reservoir caps inside the amp and are not drawn directly from mains.

The Amps is an IMG 800D.
Its an Dual Mono PA Amp and it has clipping indicators and it uses the clipping indicators from the modules, i didnt measure clipping because i cant ,thats the problem .And the Problem i need Amps with clipping indicators or big enough Amps that dont clip.

Or Probably a device i can connect beetween Amp and speakers that shows me clipping.

Understand the Problem with the caps(saw it when i looked at the momentary power consumption that there is a time the caps are loading),but with power consumption device i could play very loud music with no dynamics or perhaps a single tone .It shows also the power consumption in x Hours.

Probably the kw/h the amp has needed in one hour.

Not sure how many Power i need to play the Klipsch RF7 MK3 at their max level the 250 Watt RMs 1000 Watt Peak and 99db intensity(minus5) are 94 says also nothing .

And i cant find anything in the web.The oly i find is "buy an Amp with 250 RMS max " but at what 4 or 8 Ohm the speakers are rated 8 Ohm but most people say theire are 4.

Others say buy an amp with 1/3 more Power.

What i know if i use the IMG 800d (2 hypex UCD400 und 2 Power supplys and some additional caps) or ansingle IMG 1000D (one pascal spro 2 250/500 Watt) it runs into clipping when i play loud stereo music.

So i think when i connect an Purifi Evali 1 (i have lying some arround) it also clips but it has no indicator.

An other idea was ading an Amp switch , so that i can connect 2 amps for the front, using the Purifi for movies and using the more powerful ice or pascal for stero using.

Another idea the NCx 500 has an onboard clipping indicator, but most OEm Facturers dont connect it.

Is ist easy to connect.

I connected it on the icepower 1200 As1 modules there was one pin for current clipping and one for voltage clipping.


Other idea was to bi Amp the speakers but simple biamping with the passive crossovers is not good.

Only with an active crossover it really makes sense , than using purifi for the highs and ice or pascal for the subs) But thats a lot of cabeling couse it is not an stereo setup its an 7.3.6 Atmos Setup.

the t.racks DSP 204

Digital Loudspeaker Management System 2 XLR inputs, 4 XLR outputs, 96 kHz sampling rate, 32 Bit DSP, 24 Bit AD/DA converter, USB and RS232/485 interface, Ethernet interface, Dimensions (W x H x D): 480 x 45 x 245 mm, Construction: 19" / 1 U

www.thomann.de

 

[solderdude]

Clipping indicators on amps themselves are the only valuable thing, providing they trigger at least a monostable multivibrator that is long enough to make a LED blink long enough visually.

When one is obsessed about clipping buy yourself a cheap O-scope and learn to use it properly.
All the guessing and measuring with not suited test gear/signals is rather pointless IMO.

When you need the sound to go noticeably louder you need to increase the power 2 to 3 fold at least.
Adding a few percent in power won't help.

 

[Mario Soldier]

Clipping indicators on amps themselves are the only valuable thing, providing they trigger at least a monostable multivibrator that is long enough to make a LED blink long enough visually.

When one is obsessed about clipping buy yourself a cheap O-scope and learn to use it properly.
All the guessing and measuring with not suited test gear/signals is rather pointless IMO.

When you need the sound to go noticeably louder you need to increase the power 2 to 3 fold at least.
Adding a few percent in power won't help.

You are of course right.Buying an occiloscope is not a problem for me,ist also an good idea couse i have an car repair sevvie but not for elktronics for mechanics.
I hOpe i can lear hoow about using such a thing.
And you are right this unreal measurements confuses me more that i am.....

But one thing again withe the pascal spro2 in BTL Mode 900/1000 Watt i am far away of clipping and of course with an dual mono Icepower 1200 As1 (rated 600/1200) i am aslo far away. I know it for sure with the pascal for sure it has indicators.

The pascal only clips if i am using one amp for both speakers (but also late) .

In my head rumor the idea to use better modules from Hypex ,Purifi etc. The Stronger Purifi Module the 1ET7040SA bring no improvement over the ET400 at an speaker rated 4-8 Ohm with its lowst dip at 3,8 Ohm.

Every night i have in my head using better modules, but i have the fear running out of power with them.

The Purifi stays clean till 280 Watt 4 Ohm and has an max output of 380 Watt 4 ohm. It is rated 200/400

The icepower is rated 600/1200 and if the icepower curve is correct ist is clean till 500/1000 Watt (this is triple the power).

And there is an new icepower module same size ist rated 1400 8ohm 2000 Watt 4ohm , But i know the As12001 in Dual MOno dont Clips.

The 2x 400 watt UCD amp (with clipping indicators) also will clipp very late but it clips.

The New Hypex NCx500 is better rated 400 8ohm and 700 for 2 and 4 ohm and it stays clean till 440 Watt at 4 ohm. (but is it enough?) , it seems Buckesy Ncx 500 amp has no clipping indicator but his Purifi Amp has.

Than i had some ideas of bridging two Ncx500 Modules or Nilais or Purifis (but Purifi say dont bridge but VTV does i dont understand.

Or should i stay with my old Front Amps they are Powerfull enough and dont clip.

And the Question if i hear a difference to the hypex i think no.



What Ocilloscope should i buy ?

 

[solderdude]

Or should i stay with my old Front Amps they are Powerfull enough and dont clip.

And the Question if i hear a difference to the hypex i think no.

I cannot answer those questions.

What Ocilloscope should i buy ?

Is it only to view a clipping level of speaker signals (10-100V AC) or for more serious measurements as well ?

 

[levimax]

I have a cheap digital Oscilloscope that works with a lap top but it does have "recording" mode where you can record the peak voltage levels. I measured across the speakers with music to see how high the peaks were to make sure my amps weren't clipping (I know the clipping voltage of the amps). One thing I discovered is the type of music makes a huge difference on the peaks, modern compressed music does not need much headroom but older pop recordings or classical does. I was actually surprised how much peak voltage dynamic music required at moderately loud levels. Here is another idea to accurately measure peak power (amps and volts) of music played, you don't need a Oscilloscope just a multimeter and a few parts, I have not tried it but everything I have from this site works as described. https://sound-au.com/project189.htm

 

[Philbo King]

Below is the schematic for measuring the speaker impedance from ANSI/CTA-2034. It can also be used to measure the power into the speaker. You use a 2 channel DAC ADC (or oscilloscope or data acquisition system) to measure voltages V1 and V2. V1 is the voltage across the speaker, and V2 along with R_sense, gives the current. You can ignore Z_w (speaker wire resistance) and S2 (back EMF voltage from the reactive speaker load). R_sense, the current sense resistor, is typically 0.1 ohm. For Figure 9:

Voltage across dummy load speaker = V1​

Current across dummy load speaker = V2 / R_sense​

View attachment 276109


Below is an example (voltage and current into a power supply) of the type of data you can expect for a complex waveform into a complex load.

View attachment 276112


Apparent power is calculated as the RMS voltage times the RMS current (over a certain period of time). Real (active) power is the time averaged product of instantaneous voltage and current. Power factor is the ratio of the real power to apparent power, which is also the cosine of the phase angle between voltage and current.

View attachment 276111

^^this is the best way to do a measurement of actual VAR delivered to a speaker.
Note that the voltages V1 & V2 are measured at ungrounded points. So it is best done with a 4 channel scope using differential measurements.
V1 = Ch1-Ch2
V2 = Ch3-Ch4
Since a speaker is reactive rather than resistive, the result units are volt-amps-reactive (VAR) rather than watts. Put another way, the result is apparent power rather than true power.
Math operations could be applied to get true power if the phase relationship between measured voltage and current is taken into account, and then further processed to get an RMS wattage value. A lot of work to get a single wattage number for a single frequency...

It is far simpler to get a reading of power delivered to a resistor.

 

[Philbo King]

Something must be wrong. I set up a 440kH sine and measured from the speaker outs on the amp, but it was only 2.9mV. I had to use the 200mV setting on the DMM to get anything. What measurement did I screw up?

440 kilohertz is not audio, it is RF.
Assuming you mean 440 Hz:
1. Make sure your meter specs indicate it can measure that freq (some are accurate only at power line freqs, some are good to 1000 Hz, and expensive ones are good to 100 KHz).
2. Make sure the meter is set to AC volts, not DC volts. (On a DMM, DCV usually indicated by a flat line icon, ACV by a sine wave icon)