Acoustic music energy distribution

[hyperknot]

I'd be interested, that for acoustic music or human voice (that is non-electronic music), how is the energy distribution over frequencies. I'm asking this because I'd like to know if a Topping PA5 or a Hypex NC122MP would be objectively better for acoustic music.

Basically, here is a mix of the two amplifier's THD+N over different frequencies.

PA5 is worse in high frequencies, but only above 2 W. My suspicion is that it's possible that I'd never need more than 2 W at above 10 kHz, so it doesn't matter, because the majority of the energy goes to the lower freqs. But it's just a suspicion. What is the science behind it?

 

[voodooless]

I think it's something like this:

So at 1Khz, we're already 15 dB down, so only 1/32th of the power of the 70Hz notes. So if you have 100W going into the bass, 1Khz would only need about 3W. At 5Khz it's 30 dB down, so 1/1000th the power! your 100W bass tone will only be accompanied by 100mW of 5Khz.

Note that these are averages. With a crest factor of around 10 for music, you may still need to multiply these numbers x10 for something resembling a peak number.

 

[Lambda]

My suspicion is that it's possible that I'd never need more than 2 W at above 10 kHz, so it doesn't matter, because the majority of the energy goes to the lower freqs. But it's just a suspicion. What is the science behind it?

Your not gonna uses a separate amp for every frequency.
This is single frequency test in a restive load. even if you only need 2"W" at >10Khz you surely need >2W at the same time <10Khz.
The question is how mush get the high frequency modulated by low frequency load/power.

With a real load current and voltage are in phases most of the time.
Your amp is not outputting Real Watts but your have to make sure it can provide needed Current and Voltage.

 

[hyperknot]

I think it's something like this:

So at 1Khz, we're already 15 dB down, so only 1/32th of the power of the 70Hz notes. So if you have 100W going into the bass, 1Khz would only need about 3W. At 5Khz it's 30 dB down, so 1/1000th the power! your 100W bass tone will only be accompanied by 100mW of 5Khz.

Note that these are averages. With a crest factor of around 10 for music, you may still need to multiply these numbers x10 for something resembling a peak number.

Thanks. But 100W is already with a lot of crest factor in my opinion, at least in normal desktop listening setting I don't think I'm ever listening more than 1-2W. So based on this, in real world music the PA5 profile could be quite good, with the highs never even going into the high-distortion range.

 

[voodooless]

Thanks. But 100W is already with a lot of crest factor in my opinion, at least in normal desktop listening setting I don't think I'm ever listening more than 1-2W. So based on this, in real world music the PA5 profile could be quite good, with the highs never even going into the high-distortion range.

By that logic you could just use a beefy headphone amp with even lower distortion Or something like this: https://ggianluca.wixsite.com/opamplifier

Also, they are still averages. This is really tricky. If you have a low tone with a 50% duty cycle, and a high tone with a 1% duty cycle, they might still need the same power, but on average, the low tone will be "louder". So really you'd want to have the average of the peaks per frequency to really give a better picture.

 

[MZKM]

at least in normal desktop listening setting

Well, I don't think anyone has ever needed more wattage for a desktop setup, you probably don't even need 10W max for any consumer speaker.

It's living room setup where some people sit 12-20ft away that wattage becomes more important.