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How much power does an amplifier need with this type of range of dynamic music

EdTice

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PA has its challenges and you should perhaps not mix PA and home Hifi. Although for home Hifi you can use some PA stuff (I doubt, however, that deiked home Hifi is used in PA). What I mainly think of is the powerful PA amps that power subwoffers for home Hifi use.:)
Nobody here is suggesting (I don't think) that you mix PA and HiFi although many people use PA amplifiers (locked in a closet) as part of home theater systems. The thread is about how much amplifier power you need. HiFi presents challenges that PA does not. In PA, you assume very large crest factors and you get a lot of power. When in doubt, you get more power (Sorry for those who never saw Home Improvement) and give up some SINAD. In HiFi, we need only a fraction of the power and care much more about SINAD. The hard part is that, for HiFi, there aren't good tools for estimating power needs. Therefore, people (quite reasonably) try to use the calculators provided by Crown. Because something is better than nothing.
 
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DanielT

DanielT

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Nobody here is suggesting (I don't think) that you mix PA and HiFi although many people use PA amplifiers (locked in a closet) as part of home theater systems. The thread is about how much amplifier power you need. HiFi presents challenges that PA does not. In PA, you assume very large crest factors and you get a lot of power. When in doubt, you get more power (Sorry for those who never saw Home Improvement) and give up some SINAD. In HiFi, we need only a fraction of the power and care much more about SINAD. The hard part is that, for HiFi, there aren't good tools for estimating power needs. Therefore, people (quite reasonably) try to use the calculators provided by Crown. Because something is better than nothing.
Abosuot, each thing in its proper place, different worlds.:)
(but sometimes they meet, as. I mentioned PA amp as sub amp for home use)

The calculators in the thread give an indication in any case. Some support about what may be needed in the form of power.

You can turn it all around. How low sensitivity (and listening distance, music dynamics / crest factor) can the speakers have when choosing this:


... instead of this?


SINAD of course, but amplifiers can be driven into clipping.
 

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DanielT

DanielT

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I figured out something about amplifier power. If you're doing EQ, keep this in mind if you raise:

From another forum:

"You should not raise the level more than about 5 dB, because this means 3 times higher power output from the amplifier and almost double the cone displacement in this particular frequency band. You therefore run a high risk of audible distortion problems or amplifier clipping with excessive level increases. This means that there are extra big advantages with high amplifier power and speakers that exhibit high efficiency and low distortion during equalization because you then have more margin for raising the lows.

The whole thing is still always a balance of maximum sound pressure level versus the smoothest possible frequency response. You often get away with leaving narrowband valleys as they are because the audibility is low.

However, reducing the level by 10-12 dB is always excellent. This is also not at all unusual in normal listening rooms with concrete boundary surfaces."

 

Wesayso

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It would all depend on what's available. Get enough volume displacement and a powerful amp and you can easily go beyond that number (with care).
About the narrow-band valleys, it never is a good idea to just blindly boost at such a frequency anomaly. If it is a valley, happening due to a reflection, all the energy in the world isn't going to solve it. Find out what does what, if one does use boost, watch the distortion graphs + frequency curve to see if adding energy really does level the frequency drop.

In more simple terms, one cannot EQ a null. If it happens at a low enough frequency, say below 80-100 Hz, maybe another driver can take the 'bump' in EQ while dropping the energy at that spot of the driver that suffered the dip. At such low frequencies it's always a good idea to have more drivers carry the load. Say: 2 mains with low end performance (running full range) plus 2 subs. One can then use one where the other falls short. Maybe even keep the bass full stereo, as that does have benefits beyond what's often assumed.
 
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DanielT

DanielT

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If you have a lot of power, you have a lot of headroom to play with.:)

How much is needed then depends a little on various factors, what is mentioned in the calculator:
Plus adding extra headroom if EQ is needed. How much depends on the conditions, good thing you mention it Wesayso! :)

Also, bass requires more power than treble. Subbass requires a lot of power. So you should also work with it, factor it into the equation.
Plus there are "naughty" speakers with nasty low-dipping impedance that require an amplifier that can handle it. So there is a bit of one and the other to weigh in.

I think in most cases it makes sense to use some subwoofers and have HP-LP filters between them and the speakers. For subwoofers, powerful deiced subwoofer amps.Then for the speakers take care of everything above 80-100 Hz and you drive those speakers with other amps.

For example a mix with, class D subwoofer amp, class AB which drives bass/midrange between 80Hz -100 Hz up to around 1500Hz-2500 Hz and the treble, let's say to make it a bit extreme a class A, Single End Tube amplifier with few watts driving some compression drivers that have a sensitivity of 108-110 dB. So you can mix, if you want.

Now I'm not a tube amp guy as such, but why those who use tubis don't unload it and let a powerful class D amp take care of everything below 80-100 Hz I don't understand. I see only advantages in doing so.:)

Edit:
Regarding poweing tweeters with tube amps, I think that some tube amps roll off early in the higher frequencies in and of themselves.Maybe not so good tube amps do that? Someone else who knows tubis can maybe explain that? :)
Poorly designed class D amp can have high (audible?) distortion in the higher frequency registers, I might also add.
 
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DanielT

DanielT

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It would all depend on what's available. Get enough volume displacement and a powerful amp and you can easily go beyond that number (with care).
About the narrow-band valleys, it never is a good idea to just blindly boost at such a frequency anomaly. If it is a valley, happening due to a reflection, all the energy in the world isn't going to solve it. Find out what does what, if one does use boost, watch the distortion graphs + frequency curve to see if adding energy really does level the frequency drop.

In more simple terms, one cannot EQ a null. If it happens at a low enough frequency, say below 80-100 Hz, maybe another driver can take the 'bump' in EQ while dropping the energy at that spot of the driver that suffered the dip. At such low frequencies it's always a good idea to have more drivers carry the load. Say: 2 mains with low end performance (running full range) plus 2 subs. One can then use one where the other falls short. Maybe even keep the bass full stereo, as that does have benefits beyond what's often assumed.
I thought this was interesting. How we sum up the valleys and peaks in the higher frequencies into a whole. It is smart to EQa what matters and avoid irregularities in the FR that our ears, hearing system, anyway make sure to sum up to a smooth whole. :)


Edit:
So you don't waste power unnecessarily, that is. I know you know this Wesayso but for others reading this thread it may be new knowledge.At least for me it was before I saw that video.:)
 
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