How much power do I need?

Very interesting. I just used an amplifier gain calculator to see how much power I need for 10 and 20db headroom at an spl of 80db at 12 feet listening area from the speakers. For my Magnepans with a sensitivity of 86db I need 33 watts for 10db headroom and 336 watts for 20db headroom. I am really appreciating the fact that my Pass amp is 500wpc and can give instantaneous peaks of over 3 times that.

The link for the spread sheet is below


www.careysound.com/oldsite/downloads/.../Amplifier%20Gain%20Calculator%202.xl...

The above link does not work so here is another calculator-

https://geoffthegreygeek.com/calculator-amp-speaker-spl/
 
Here is food for thought. Using the same calculator as above in my previous post. If I increase the spl to 85db then I need 106 watts for 10db headroom, 336 watts for 15db and 1,063 watts for 20db. And I do most of my listening between 75 and 90 db.

You can see why cheap speakers like the Elac B5's that have a sensitivity of 85db really sound better with high powered, high quality amps. Andrew Jones recommend at least 100wpc to get the most out of them. They are budget speakers at $220pr but need a not so budget amp to make them sing.
 
a.wayne said:
Man Imagine those peaks with only 100/100 , clip city ..... :)
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LOL!

That's why at the Newport Audio show a couple of years ago when the B5's debuted that he used Bel Canto amps and people were blown away by the sound of them.
 
Bottom line to me is that is is quality over quantity! A quality First Watt (and ARC) amp gives me more pleasure than a quantity of someone else amp. 50 watts high performance versus 300 watts of good but not as good.... I will take the 50... PERIOD. My ears hear the difference.
 
KeithR said:
I have 91db/8ohm speakers and can confirm 15 watt average peaks regularly in a smallish room and have seen one 30 watt blast from the end of a super dynamic orchestral piece.
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Keith. If you told me this few days ago I couldn't agree with you more ! However now I pair my 96db speakers / 8 ohms with 1,000 watts amps just changed whole my view. Wow. What a difference.


Sent from my iPhone using Tapatalk
 
Personally I find the whole wattage discussion a difficult one.

I agree with the people here that you need a decent amount of watts to have enough dynamic headroom. However when talking about watts do we talk about a stable 8 Ohm load or a more variable load. Some time ago (don't ask me about brands/models cannot remember) I heard some speakers driven but an amp that was powerful 200 watts or something. However it always sounded out of breath. It was then replaced but some 50watts amp and it sounded much better.

Reason was the 50watts amp was far more stable while being stressed with a speaker that dipped well below 4 Ohm something like 2.5 Ohm.


IMHO the impedance curve of a speaker is just as important as the efficiency of a speaker when choosing an amp.
 
Mordante said:
Personally I find the whole wattage discussion a difficult one.

I agree with the people here that you need a decent amount of watts to have enough dynamic headroom. However when talking about watts do we talk about a stable 8 Ohm load or a more variable load. Some time ago (don't ask me about brands/models cannot remember) I heard some speakers driven but an amp that was powerful 200 watts or something. However it always sounded out of breath. It was then replaced but some 50watts amp and it sounded much better.

Reason was the 50watts amp was far more stable while being stressed with a speaker that dipped well below 4 Ohm something like 2.5 Ohm.


IMHO the impedance curve of a speaker is just as important as the efficiency of a speaker when choosing an amp.
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This is correct , but thats for a different discussion , currently we are discussing quantity necessary , many other factors will influence the actual amount necessary, such as , impedance /phase angle/sensitivity /listening distance / music genre/listening levels/room noise floor/ system noise floor / speaker topology , on and on...


Hence the over simplification for discussion, seeing how the majority of audiophiles systems are under powered ..


regards
 
a.wayne said:
Thats academic Randy , No one is advocating the use of substandard amplification ....
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My point was of course considering quality also, and of course budget concerns. At a certain price point I could get some very good amplifiers that sound excellent with a lot more power, or a much lower power rated amplifier that is in a whole other world performance wise. Yes, if the budget could handle more getting a larger version of the higher performance level may be warranted, within reason.

My second point was there have been several manufactures who recommend turning the volume control up a bit to get best performance. This is irregardless of the amount of power. Some state that best performance can only be achieved by turning the volume up control past the 11 o'clock position. Therefore, to obtain top performance having too much power can actually be a hindrance if the system has to driven to uncomfortable levels to achieve top performance.
 
Hello Randy,


Then that would be a gain issue not power , power is only relative to preamp /amp gain structure .


BTW all pre-amps have a sweet spot in regards to volume pot level , hence the suggestion by some manufacturers..


regards
 
Current is where its at.....the more current an amp can deliver, especially into 2 ohms, is the figure to look at.

If the figure is consistant from 8 to 2 ohms, its a good indicator the amp is designed properly.

Also, if the specs don't give a 2 ohm figure, you have to wonder.........
 
a.wayne said:
Hello Randy,


Then that would be a gain issue not power , power is only relative to preamp /amp gain structure .


BTW all pre-amps have a sweet spot in regards to volume pot level , hence the suggestion by some manufacturers..


regards
Click to expand...

Understand, but with too large of an amplifier for use/needs the volume control range would be limited (which is exactly what i was experiencing).
 
well I have 200wpc/8ohms SS doing 2 sets of Heil speakers..1 at 90db 6ohms and the other 94db into 4 ohms and no issues. the latter is significantly louder/ more upfront and fuller (bass to 28hz vs 40hz). The amp is modded with overcompensation (negative output impedance) and I am told will be able to handle up to 750w into 1 ohm for short bursts...so no danger of engaging the protection circuitry.

Of course for normal listening the 94db speaker will max out at 9o'clock AM on the amp dial vs noon for the other.

I can run them like this since all Heil AMT speakers are always perfectly in phase. I am pretty sure That I can mostly avoid any peak level compression with this amp setup.
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In my old system I was likely never listening to more than 5 watts. The voltage never changed across the speakers. Did not need any more of my 150watts.

Sent from my PRO 5 using Tapatalk
 
I have a speaker 98 db and amp CH M1 mono,
i always listen with 2/5 watt but one time listening Albert King and Stevie Ray Vaughan at high level i saw the M1 display arrive at 818 watt
Was very impressive.
In last 15 years i had Audio Tekne and Kondo with 8 watt,but now i like this big power sometimes
 
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