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Science: How much power do you really need?

solderdude

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#2
It depends on:
room size, efficiency of the speakers, power rating of the speakers, expected SPL (how loud you want to play) and perhaps even on music genre (DR).

There is no single correct answer. For some circumstances arguably 8W would be enough, for other situations 800W isn't enough.
 

tktran303

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#3
Hello,

Of course.

That’s why the above test takes all those factors into account.

All you need is to be able to follow the directions, and have a voltmeter handy... take this fun little science experiment and see...

Unfortunately, Pano doesn’t explain the algorithm or maths until a lot later in the thread. Before the arguments start trickling in, read further.
For those not interested in the maths, it’s explained a bit better here:
https://archimago.blogspot.com/2017/09/musings-how-much-amplifier-power-do-you.html
 
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solderdude

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#4
In my younger years I built a super fast peak level meter that can be connected to an amps output and while usually having enough with 10W for normal listening there were times my 200W amp reached clipping and the SPL wasn't that high at all. (speakers about 88dB/m)
So while fun to experiment I am of the opinion that having more than enough headroom can't hurt and will be least harmfull to sound.
 

Sal1950

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#6

RayDunzl

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#7
Science: How much power do you really need?
So far, just part of a 120Vac 15amp branch circuit has been more than enough at home.

The band used to pop breakers at The Liquor Lodge, but I'd blame a little indiscretion with the the lighting dimmers for that.
 

solderdude

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#10
The calculator determines peak levels.
These numbers usually are MUCH higher than the average levels measured in dBA (or Phon) ?
I would argue that 104dB peak levels may well exist in music with 85dB average levels.
 

Sal1950

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#11
The calculator determines peak levels.
These numbers usually are MUCH higher than the average levels measured in dBA (or Phon) ?
I would argue that 104dB peak levels may well exist in music with 85dB average levels.
If you have REW and a UMIK with it's calibration file your all set to measure true peak levels.
The actual numbers might surprise you.
Mr @RayDunzl done learned me dis. :D
 

RayDunzl

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#13
I've had 1000 wpc on my speakers, and it was almost enough.
I think I remember seeing 50V on the speaker leads sometime in the past...

50V 4 ohms = 625W

Not being sure if that was RMS or Peak, measuring the AC with the Fluke line shows 114V, or if the MIN/MAX setting is used, still 114V, so, not a peak reading (would be 161V).

50V x 1.414 = 70.7Vpk (more or less)

70.7V 4 ohms = 1249.6Wpk

So, yeah!

But in my case, it was enough.
 

Tks

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#15
Of speakers I have no clue about (my setup is a laughable set of desktop speakers running from the RCA out's from an RME).

But with respect to headphones, I don't understand a single person talking about needing "power". Even on the RME, I can plug in a pair of HD6XX in the IEM port and max out the volume from source and DAC, and still feel like my head is about to cave in with modern (DynamicRange ~7 rated) tracks. Switching to the Phones-out at max.. I don't care if the DR rating is 15+ .. once a crescendo come along, I feel either my ears or the drivers are due to for "warranty" services.

I think about the THX 789 hopefully coming in at the end of the summer, and look at the power specs that thing can output from the balanced out. And I am left perplexed. On what planet is "headroom" lacking in modern devices these days I wish I knew.

The same goes for the DX3 Pro..

So if anyone can teach me what people on other forums are talking about with respect to headphone amps not having "headroom" I'd love to be educated on that.

"lower frequencies demand more power, thats why you want more headroom so that doesn't come out anemic" is a concept I can wrap my head around. But if I'm not maxing out the volume, and for instance stay somewhere in the -5 to -1 dbFS range to prevent clipping.. What exactly is this missing headroom considering my ears are about to blow up?
 
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#16
I did an article on this, recently: https://www.kvalsvoll.com/blog/2018/12/02/how-much-power-do-i-need/

Tried to make it simple and easy, but obviously failed at that.

However, the article looks into things like what happens when you limit the frequency range - does power requirements go down? Is it likely you can reach the limits of say a 200W amp with traditional low-efficiency speakers? How to estimate spl requirements? What if you never play loud?

Don't know if this article is useful for anyone, but surely the audience for this rather complicated answer to a simple question must be on this forum.
 

tktran303

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#17
Switching to the Phones-out at max.. I don't care if the DR rating is 15+ .. once a crescendo come along, I feel either my ears or the drivers are due to for "warranty" services.
...
...
"lower frequencies demand more power, thats why you want more headroom so that doesn't come out anemic" is a concept I can wrap my head around. But if I'm not maxing out the volume, and for instance stay somewhere in the -5 to -1 dbFS range to prevent clipping.. What exactly is this missing headroom considering my ears are about to blow up?
The truth is that for MOST headphones, and MOST music, the iPhone with it's 1V RMS output is enough. And you've experienced it for yourself.
But say that on a public forum and people will think you're clueless, or an Apple lover.

My cynical answer would be- audiophilia nervosa is a disease of anxiety- it causes worry amongst audiophiles that there MIGHT NOT be enough. They want more, just in case. If you call it "headroom" it makes it more legitimate.
 

solderdude

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#18
For low impedance headphones and certainly IEMs 1V is usually enough.

Some headphone outs of phones roll-off in the lows when a low impedance headphone is connected which is not the case with most external amplifiers.
When you want to play higher impedance headphones distortion free to comfortably loud levels you will definitely need more than 1V.

Note the cynical answer doesn't fly in all cases but indeed does in a lot of cases, certainly for low (comforatble long duration) listening levels ;)
 

Peter Leyenaar

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#19
Ever since some moron drove a golfball at full velocity into the back of my head , 90 degrees off the intended direction, my hearing
has been super sensitive , so I only listen to my system at about between 40 and 60 db, a 65 Watt KT88 tube amp. into a pair
Dali Helicon 400, 88 sensitivity, in a room 20 x15 feet with the front of the speakers approx. 4 feet from the wall, the listening position
about 12 feet from the front of the speakers.
The 65 watts seem more than adequate even if I crank it up to 75 db
Orchestra conductors must incur some serious auditory problems with the SLP at the conductors position:
for example conducting Saint-Saëns symphony No 3
 

tktran303

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#20
For low impedance headphones and certainly IEMs 1V is usually enough.

Some headphone outs of phones roll-off in the lows when a low impedance headphone is connected which is not the case with most external amplifiers.
When you want to play higher impedance headphones distortion free to comfortably loud levels you will definitely need more than 1V.

Note the cynical answer doesn't fly in all cases but indeed does in a lot of cases, certainly for low (comforatble long duration) listening levels ;)
I measured my old phone (iPhone 6; 2014 release) as +0, -0.08 dB from 10Hz to 20Khz and output impedance of 3 ohms, THD -94dB and SNR of 103dB. This perceptually transparent for as far as I’m concerned.

But can it go loud or clean enough?
The phone can only output 1V RMS into a 600ohm load and about 0.9V into a 32ohm load.

I have a Sennheiser HD600 and when listening from my phone, for most program material I’d at 3/4 max volume to 1 click down (-3.5dB) from maximum volume.

I only use a headphone amplifier for music that recorded with higher dynamic range eg. Classical or jazz
 
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