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What Grinds My Gears, POWER METERS

Dingman said:
I think dB is a better measurement, but none of them actually measure watts in a meaningful way, do they?
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While we're at it, quit calling quasi VU or Peak Meters VU meters. Real VU meters indicate average levels, they have specific ballistics. They cost real money to manufacture, so much so, very few non professional items have them.
 
The meter movement is typically specified as how much current fully deflects the needle, as in 50, 100, or 200microamperes full scale, 600ohms.

I had a pair of big beautiful 4x5" meters. In order to use them, I had to do some calculations and estimates, then experiments with various resistors to "register" the apparent watts indication with what I initially figured from my speaker sensitivity and SPL meter. I used diodes to rectify the signals. The final test was using a VTVM and AC probe to see the actual AC signal voltage magnitude (to compute and confirm the meters). All of that calculated out right...

Unfortunately, my speakers only need milliwatts to fill the house and the "correctly scaled" meters hardly moved... so I just re-scaled them by changing the resisters until my usual average listening level pushes the needles up about straight up on peaks ("peak meters" indicate about 12dB below true acoustic peak transients).

And, this reveals why the meter motion is and must be the way it is - the peaks on a linear scale meter would be HUGE, variations about average level would be INVISIBLE.
 
So, it sounds to me like the best meter would show both peak, clipping and average watts - with fast fast display.

So, LED is the way to go? Fast, easy to have a clipping LED, Average via staged and a memory type peak like the cassettes used to have?

Hmmm, so does this mean cassette meters are a better solution than power amp meters?
 
A lot of "Pro" amps have clipping indicators. I suspect many would be surprised by how many watts they are actually using and how often those clipping indicators light.
 
I can't speak for other meters but the ones in my Kenwood power amp have 3 ranges. 0db, - 10 db, and - 20 db. According to the manual when the meter needles reach 0db with the - 20 db range selected the amp is putting out 1.7 watts. With - 10 db selected, when the needle hits 0db it is producing 17 watts. With 0db selected and the needle is at 0db the amp is producing 170 watts.

How accurate this is in terms of output sound in db is debatable. How would frequency play into it? Still playing with my old JBL's which are rated for 80 db with1 watt at 15 feet, where the power level meters would indicate that the amp is producing about 1 watt the db meter on my phone shows somewhere around 80 db. Before anyone jumps on me, I fully realize that this is not an accurate way to measure anything, but it is at least a visual indicator of power levels.

So why would we need all of this accuracy from a power level meter when listening to music anyway? All they are really for is to give you a visual indication of power, not the exact level at any one moment which is constantly jumping all over the place when music is playing anyway. Maybe if you liked to listen to a constant tone it may need to be more accurate but I find listening to frequency tones boring.
 
Alobar said:
I can't speak for other meters but the ones in my Kenwood power amp have 3 ranges. 0db, - 10 db, and - 20 db. According to the manual when the meter needles reach 0db with the - 20 db range selected the amp is putting out 1.7 watts. With - 10 db selected, when the needle hits 0db it is producing 17 watts. With 0db selected and the needle is at 0db the amp is producing 170 watts.

How accurate this is in terms of output sound in db is debatable. How would frequency play into it? Still playing with my old JBL's which are rated for 80 db with1 watt at 15 feet, where the power level meters would indicate that the amp is producing about 1 watt the db meter on my phone shows somewhere around 80 db. Before anyone jumps on me, I fully realize that this is not an accurate way to measure anything, but it is at least a visual indicator of power levels.

So why would we need all of this accuracy from a power level meter when listening to music anyway? All they are really for is to give you a visual indication of power, not the exact level at any one moment which is constantly jumping all over the place when music is playing anyway. Maybe if you liked to listen to a constant tone it may need to be more accurate but I find listening to frequency tones boring.
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The actual reading on those meters depends on the impedance of the speakers at that particular moment based on the frequency being reproduced. Most of that is covered in post #24.

No one, least of all me, objects to any sort of meter. I, like many, like to look at them. They are cool. The problem arises when some take the readings as gospel and proclaim something like, "at my normal levels I'm using only "x" Watts". We (some of us) know that the meter readings are largely completely inaccurate. Unfortunately, many don't know this.

Using a pro amp or any amp with clipping indicators for a day or two can be a real eye opener. I regularly see the clipping indicators illuminate on my brother's Crown XLS-202 (200WPC @ 8 Ohms) driving 6 Ohm Pioneer SP-FS52's at only moderately loud (peaks of 95dBA) levels in a medium sized room.
 
I much prefer the columns on my MPI-4 Indicator from Mcintosh. The response time is much faster and you can select levels from less than a 1/10 of a watt to over 1000 watts in 5 db steps. It also has an accumulate and hold mode. I prefer the linear meters of the early 2000 series, 2505, 2105 and 2300. The longer scales of the later amps have more accuracy, but just don't seem to give with the dynamics of the music like the earlier amps. Mac meters are supposed to be 98% accurate up to 2000 hz, which covers the area where most energy is located. I would prefer to see that extended to 5 khz, but with Power Guard and having the speakers that can handle the power I have no real worries.
 
JoeESP9 said:
Using a pro amp or any amp with clipping indicators for a day or two can be a real eye opener. I regularly see the clipping indicators illuminate on my brother's Crown XLS-202 (200WPC @ 8 Ohms) driving 6 Ohm Pioneer SP-FS52's at only moderately loud (peaks of 95dBA) levels in a medium sized room.
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Well I will call it eye candy then. I actually almost never pay them any mind anyhow because at the volume levels I listen, that amp is not working hard enough even with the minimum -20db range and are barely moving off the peg. Even when I was in my 20's and listened very loud rock those same meters usually stayed in the -20db range. I suppose this is more an indicator of the higher sensitivity level of the larger JBL's like mine more than anything.
 
twiiii said:
I much prefer the columns on my MPI-4 Indicator from Mcintosh. The response time is much faster and you can select levels from less than a 1/10 of a watt to over 1000 watts in 5 db steps. It also has an accumulate and hold mode. I prefer the linear meters of the early 2000 series, 2505, 2105 and 2300. The longer scales of the later amps have more accuracy, but just don't seem to give with the dynamics of the music like the earlier amps. Mac meters are supposed to be 98% accurate up to 2000 hz, which covers the area where most energy is located. I would prefer to see that extended to 5 khz, but with Power Guard and having the speakers that can handle the power I have no real worries.
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I've already posted that that Mac meters are the exception to the rule.

Alobar said:
Well I will call it eye candy then. I actually almost never pay them any mind anyhow because at the volume levels I listen, that amp is not working hard enough even with the minimum -20db range and are barely moving off the peg. Even when I was in my 20's and listened very loud rock those same meters usually stayed in the -20db range. I suppose this is more an indicator of the higher sensitivity level of the larger JBL's like mine more than anything.
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Yes they are IMO mostly eye candy. In defense of the eye candy thing, I've already posted that I like looking at them.
IME clipping indicators flash when it's not expected. They are much more accurate than most any meters.
 
Aesthetics..

But, if your equipment supports Quad, they really do "show" the four channels difference.

I'm actually building a Quad pre, and adding as large set of vintage VU as possible.

So, are they accurate?
Yes.
I am sure all major high end gear, is.

And sourcing a vintage VU, and the original schematic, I can match their performance. But, the affect for me will be evident irregardless of its true accuracy.
 
I picked up a Pioneer SA-7700 integrated. It produces a min. of 60 watts and the meters register up to 100 watts. Above each meter, there is a Peak red light to indicate any clipping. Maybe the best of both worlds?
 
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