Why so MUCH Power?

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AmpDesigner333

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Why so MUCH Power?
« on: 9 Feb 2021, 11:39 am »
With a 100W amp, you can get well over 100dB SPL!  That’s loud, right?  Think again....

Keep in mind SPL ratings are MAX, as in the very peak where things are at the edge of losing control.  This pushes the average way down if you want to handle the dynamics (peaks) accurately as well as quiet sounds.

That’s why a 1000W amp can sound so good (as in better than a 100W amp with similar performance characteristics otherwise) playing at low to moderate levels.

So, more power doesn’t mean louder average to me, just better dynamic performance.

opnly bafld

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Re: Why so MUCH Power?
« Reply #1 on: 9 Feb 2021, 01:18 pm »
 :duh:

Then as you lose your hearing you need an even more powerful amplifier.

JLM

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Re: Why so MUCH Power?
« Reply #2 on: 9 Feb 2021, 03:14 pm »
We really should measure amps in terms of dB of gain, since that is what we hear and since watts relate to dB in a logarithmic scale.  Here's a quick scale:

1 watt = 0 dB of gain; 2 watts = 3 dB of gain; 5 watts = 7 dB of gain; 10 watts = 10 dB of gain; 20 watts = 13 dB of gain; 50 watts = 16 dB of gain; 100 watts = 20 dB of gain; 1000 watts = 30 dB of gain. 

Of course loudspeakers are rated for how much power (watts) they can safely handle.  Clipping amps (especially non-tube designs) can damage loudspeakers, so in general it's best to oversize the amp.  In my experience it's best if the amp can provide a commanding grip on the loudspeaker to provide better control.

When added to rated loudspeaker efficiency (if manufacturer's ratings are to be trusted) the amplifier's dB of gain would predict the output per loudspeaker at 1 meter away in an anechoic chamber.  Loudspeaker efficiencies range roughly between 80 dB/w/m to 100 dB/w/m.  But then you'd need to know how loud is loud.  105 dB is peak jazz/classic music.  110 dB rock band.  Distance from the loudspeakers and room size must also be considered, but in an "average" room and using two loudspeakers there is about a 3 dB loss.

So average efficiency loudspeakers (say 87 dB/w/m) in an average room requires 140 watts to reach live jazz/classical peaks or 400 watts to reach rock band live levels.  Note that most loudspeakers aren't rated to handle 400 watts and lower efficiency loudspeakers could require 1400 watts to reach rock band levels. 


Early B.

Re: Why so MUCH Power?
« Reply #3 on: 9 Feb 2021, 04:50 pm »
With a 100W amp, you can get well over 100dB SPL!  That’s loud, right?  Think again....

Keep in mind SPL ratings are MAX, as in the very peak where things are at the edge of losing control.  This pushes the average way down if you want to handle the dynamics (peaks) accurately as well as quiet sounds.

That’s why a 1000W amp can sound so good (as in better than a 100W amp with similar performance characteristics otherwise) playing at low to moderate levels.

So, more power doesn’t mean louder average to me, just better dynamic performance.

Absolutely!!! 

I never understood the flea amp crowd who says, "get a high efficiency speaker and a low wattage amp." That's OK in theory, but dynamics will likely suffer. For this reason, I typically buy the highest powered amp with the beefiest power supply I can afford with my 98dB speakers. 

I recall a few years ago, I was listening to a live performance and the dynamics were through the roof. At that moment, I realized just how delusional me and my audiophile buddies have been in comparing our systems to a live performance. Sure, detail, resolution, clarity, imaging, soundstage, etc., are important, but if it ain't dynamic, it isn't realistic.
 

RDavidson

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Re: Why so MUCH Power?
« Reply #4 on: 9 Feb 2021, 05:21 pm »
A lot really depends on speaker sensitivity, listening distance, room size AND average listening SPLs. A flea watt amp can be entirely sufficient in certain cases, but I agree with the general statement that if dynamic realism is what one wants, even with very high efficiency speakers, one needs much more than just a hand full of watts. What can be difficult and possibly expensive is finding an amp that gives you the "magic" at very low levels (with very low noise), but also has the explosive brute strength to handle dynamic swings.

Saturn94

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Re: Why so MUCH Power?
« Reply #5 on: 9 Feb 2021, 05:52 pm »
With a 100W amp, you can get well over 100dB SPL!  That’s loud, right?  Think again....

Keep in mind SPL ratings are MAX, as in the very peak where things are at the edge of losing control.  This pushes the average way down if you want to handle the dynamics (peaks) accurately as well as quiet sounds.

That’s why a 1000W amp can sound so good (as in better than a 100W amp with similar performance characteristics otherwise) playing at low to moderate levels.

So, more power doesn’t mean louder average to me, just better dynamic performance.

 :thumb:

Early B.

Re: Why so MUCH Power?
« Reply #6 on: 9 Feb 2021, 06:02 pm »
What can be difficult and possibly expensive is finding an amp that gives you the "magic" at very low levels (with very low noise), but also has the explosive brute strength to handle dynamic swings.

Yep. You need a helluva amp to be both refined and brutal in the same chassis, and they ain't cheap. On top of that, if you really want the best sound with unparalleled musical separation, you'll need monoblocks. That expensive amp you've dreamed of owning someday is twice the price. :o

RonN5

Re: Why so MUCH Power?
« Reply #7 on: 9 Feb 2021, 06:57 pm »
Yes, if you listen loud, sit far away and want to be absolutely certain your system can handle dynamic peaks, you need a lot of power.  Here is an interesting article from Harman as well as a link to a calculator.

https://www.crownaudio.com/how-much-amplifier-power

In my case...85db listening (usually lower), 3.5 meters back, 4 ohm loudspeakers rated at 88db (so lets call them 85db) and lets assume 6db of headroom....I need 49 watts.  With the 2Cherry, I have 400 watts at 4 ohms...so, I'm feeling pretty good.

But if you have 87 db louspeakers, 4 meters back, 97db listening and 6db of headroom....you need 637 watts

And if you have 102db loudspeakers, 4 meters back, 88db listening level and 6 db of headroom...you need 3 watts

Moral of this story?  I'm not sure, but you better have a calculator

AvsFan

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Re: Why so MUCH Power?
« Reply #8 on: 9 Feb 2021, 08:30 pm »
Absolutely!!! 

I never understood the flea amp crowd who says, "get a high efficiency speaker and a low wattage amp." That's OK in theory, but dynamics will likely suffer. For this reason, I typically buy the highest powered amp with the beefiest power supply I can afford with my 98dB speakers. 

I recall a few years ago, I was listening to a live performance and the dynamics were through the roof. At that moment, I realized just how delusional me and my audiophile buddies have been in comparing our systems to a live performance. Sure, detail, resolution, clarity, imaging, soundstage, etc., are important, but if it ain't dynamic, it isn't realistic.
 

I am there with you. I don't get it. I've tried the fleawatt amp route twice and both times it was an epic failure. Most recently I was playing some 1.5 watt per channel 45 monoblock SET amps on my 97db efficient ZU Audio Dirty Weekends. At very low volumes with vocals and acoustics, it sounded good, once turned up it became a mess and especially with anything dynamic or with kick to it. I play a lot of industrial type of music and metal with heavy kick drums, the bass was horrible. Sloppy and not defined at all. I can see someone buying a pair of ZU's, owning a SET amp, and thinking the ZU's will sound great with the SET amp. And then thinking the speakers suck, which is certainly not the case. I didn't realize the ZU's true potential until I hooked them up to Tommy's STM. My God did they jump to life! Then took it a few steps further with his Golden Cherry Monoblocks. I couldn't believe I was listening to the same speaker. The authority and attack the ZU's played with was startling. 

Even Sean at ZU says that he LOVES high power on his speakers. That pairing his speakers with low powered amps is not taking advantage of his high efficient designs. He has told me that himself and in an interview on YouTube. I think it was either with John Atkinson of Stereophile or Steve Guttenberg, The Audiophiliac. I will post a link to that interview. Sean said you're missing the point of his high efficiency speakers. High and clean power = life, dynamics, attack and immediacy to ZU's. PERIOD. I've experienced it with my own ears.

Now please don't misunderstand my statement. I am not stating that SET amps and fleawatt amps are terrible and don't sound great under certain listening conditions and listening habits. Just not for me.  I've gave it a chance twice and I won't ever go back to low powered tube amps.

Early B.

Re: Why so MUCH Power?
« Reply #9 on: 9 Feb 2021, 11:32 pm »
I can see someone buying a pair of ZU's, owning a SET amp, and thinking the ZU's will sound great with the SET amp. And then thinking the speakers suck, which is certainly not the case. I didn't realize the ZU's true potential until I hooked them up to Tommy's STM. My God did they jump to life! Then took it a few steps further with his Golden Cherry Monoblocks. I couldn't believe I was listening to the same speaker. The authority and attack the ZU's played with was startling. 

Even Sean at ZU says that he LOVES high power on his speakers. That pairing his speakers with low powered amps is not taking advantage of his high efficient designs. He has told me that himself and in an interview on YouTube. I think it was either with John Atkinson of Stereophile or Steve Guttenberg, The Audiophiliac. I will post a link to that interview. Sean said you're missing the point of his high efficiency speakers. High and clean power = life, dynamics, attack and immediacy to ZU's. PERIOD. I've experienced it with my own ears.

Yep. There's no reason to correlate speaker sensitivity with power. You'll always benefit from higher power, period! Take the Cherry In Line Maraschinos, for example -- you can go from 36v to 48v to 60v, and at each increment, you're gonna get more of everything -- detail, dynamics, etc.

The sound is in the power, people!!!


JLM

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Re: Why so MUCH Power?
« Reply #10 on: 10 Feb 2021, 12:47 pm »
20 years ago tried to warm up to SET's but couldn't find efficient loudspeakers I liked that could handle realistic peak sound pressure levels and deep bass.  Ended up commissioning the loudspeakers I'm still using 17 years later.  The first amp I paired them with was a Red Wine audio 7 wpc battery powered Tri-Path, which sounded amazingly adequate considering the loudspeakers were rated at 90 dB/w/m (obviously not able to reach live music peak sound pressure levels).  Moving up to 40 watt mono-blocks (and gaining 8 dB of headroom) turned the loudspeakers from polite dinner guests into NFL linebackers wearing tuxedos.  Moving up again to 100 watt mono-blocks gained another 4 dB and improved the grip the amps had over the loudspeakers.

During my SET's years one of the main struggles was achieving sound pressure levels.  So bought and frequently used a sound pressure level meter (before smart phone apps) and learned what different levels were like.  Also found that the SET crowd is downright "allergic" to deep bass (which obviously fits into the lack of power of the amps), even confused when they hear it.  Amazing how we can be conditioned.  But quite rightly they rationalize the importance of the first watt, which is what most of us listen to most of the time, regardless of loudspeaker efficiency or room size.  And the old adage is that tube amps typically sound best at low power while solid state sounds best at higher power levels (don't know about class D which I now use). 

Small amp/efficient loudspeakers has an analog in the automotive field.  Collin Chapman always said that he wanted to add lightness to his cars as handling was improved with reduced inertia which applies at any speed.  In audio we want low mass drivers to improve dynamics/frequency response.  Thus shorter circuits/wiring, lighter drivers, etc. are desirable. 

sebrof

Re: Why so MUCH Power?
« Reply #11 on: 10 Feb 2021, 10:32 pm »
Regarding low power SET and efficient speakers, some of the best sound I ever heard was when I had a 3-watt 2A3 SET amp with some older Tekton (Kat’s Meow) speakers in a small room. Music was surreal, the SET magic is for real and I can totally understand why people go that route. Unfortunately for me that was only about 25% of my listening ‘cause when I wanted to play more complex music louder it got compressed and not so great. One of these days I’ll have both my main rig in my loft and a similar SET system in a tiny room.

grsimmon

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Re: Why so MUCH Power?
« Reply #12 on: 11 Feb 2021, 12:09 am »
Sorry I'm asking this in the Digital Amplifier Co.  circle,  but this thread got my attention and am enjoying the responses.

I'm curious to hear anyone's thoughts (even generally speaking) about this topic,   but for multi-channel amps.   I may be in the market for a 5 channel amp:   4 channels for active bi-amp of main speakers,  and 1 channel for an 'ambiance fill' reduced-volume center channel.  I realize I could go 2 stereo amps for the mains + a mono for center,  but I need to keep things as simple as possible.  So some 5 channel amps I'm considering are:

ATI Ncore
ATI 'regular' class A/AB
ATI fully balanced monster

Monoprice (made by ATI)

NAD Ncore

Bryston

Parasound hi-bias,   (first 6 watts or so as Class A). 


Any thoughts or opinions?  Is the Parasound hi-bias Class A worth chasing?  I've heard that well executed Class D sounds remarkably similar to Class A,  but never heard myself.....  Does going active reduce my need for higher watts,  due to not being wasted in a passive crossover?  etc.





TomS

Re: Why so MUCH Power?
« Reply #13 on: 11 Feb 2021, 12:25 am »
Sorry I'm asking this in the Digital Amplifier Co.  circle,  but this thread got my attention and am enjoying the responses.

I'm curious to hear anyone's thoughts (even generally speaking) about this topic,   but for multi-channel amps.   I may be in the market for a 5 channel amp:   4 channels for active bi-amp of main speakers,  and 1 channel for an 'ambiance fill' reduced-volume center channel.  I realize I could go 2 stereo amps for the mains + a mono for center,  but I need to keep things as simple as possible.  So some 5 channel amps I'm considering are:

ATI Ncore
ATI 'regular' class A/AB
ATI fully balanced monster

Monoprice (made by ATI)

NAD Ncore

Bryston

Parasound hi-bias,   (first 6 watts or so as Class A). 


Any thoughts or opinions?  Is the Parasound hi-bias Class A worth chasing?  I've heard that well executed Class D sounds remarkably similar to Class A,  but never heard myself.....  Does going active reduce my need for higher watts,  due to not being wasted in a passive crossover?  etc.
The 5-Cherry would do the job nicely

grsimmon

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Re: Why so MUCH Power?
« Reply #14 on: 11 Feb 2021, 12:30 am »
Oh I didn't even know about that one,  thank you I'll check it out -