KalleK wrote:

> I checked our washing-machine and it takes 10W when turned off - as off 
> as it could be without unplugging it. So now, theres is an extra switch 
> in the powercable...
> This is 1.68 kWh per week - for nothing. The machine has a display which 
> is switched off in off-mode, and you turn a switch (physically) , which 
> selects the different programs, to off - so you think it should be 
> really off. But there seems to be a powerhungry powersupply generating 
> low Voltage for the microprocessor all the time or something...

Oh, that's cute.

Well, the washing machine registers a flat 0 with the dial turned to 
off. (It's a dial, not just a push button or something. So presumably it 
physically disconnects something somewhere.)

OTOH, my PC still drinks 4W even when "off", so...

> In your table you may need a thin line between the different devices, I 
> first thought the dishwasher takes up to 280W while booting ?!? Or is 
> this wordpress again?

Check the source code. It says <table border="1">. However, the CSS 
seems to think it would be funny to remove the grid lines and vertically 
center all cell contents... (Again, unfortunately there is no way I can 
alter the CSS, much as I long to do so.)

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>> Pretty tiny compared to the 20 W or so my laptop uses when idling.
> 
> Idling? Heck, if ACPI is trustable enough, I've managed to use ~35W max
> on full load with my laptop (and somewhere around 15W while running just
> SSH-over-bluetooth oslt). These babies are getting more and more
> energy-efficient - and that's a good thing.

The maximum load I saw was 40W (during the boot sequence - when 
everything turns on at once). In normal running it hovers somewhere 
below that.

>> (But then... no 3D graphics, only 1 HD, lower clock speed, etc.)
> 
> Well yeah, poor 3D, 1HD, 2x1,8GHz C2D, 15" TFT etc (the screen backlight
> is one big consumer for me, to be noted).

I didn't check specifically. My laptop has a very dim LCD with poor 
saturation and a horribly narrow viewing angle. No matter how you 
position your head, 50% of the display is always inverted...

>> We discovered that if you boot into Linux while the fans are off, they
>> stay off. And if they're running when Linux starts, they stay running -
>> no matter how cold the machine gets. Weird, eh?
> 
> I'd guess you were having broken APM/ACPI -support to get some effect
> like that. Not good, though, while it might burn your lap AND defect
> your laptop.

Should be noted: It's an *ancient* laptop!

(Now *my* laptop seems to do all this in hardware, not software. Doesn't 
matter what software is running, the fan turns on and off now and then...)

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>> Of course if you are in a call average power use will be much higher,
>> which is why "talk-time" is something like 8 hours and "standby time" is
>> usually a week or so.
> 
> I don't know anyone who gets that kind of standby time.

That would be *me* then. My phone typically needs charging once every 9 
days or so. (Bearing in mind that I never make or receive any calls or 
text messages. The phone does however tell me the correct time, which is 
more than my watch does. It also doubles as a very high power torch...)

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Orchid XP v3 wrote:

> My phone typically needs charging once every 9 
> days or so. (Bearing in mind that I never make or receive any calls or 
> text messages.)

Actually, come to think of it... usually the meter shows "full charge" 
constantly, until you actually attempt to *use* the phone. Then the 
meter instantly drops right down to empty. ;-)

As I understand it, it's just very hard to measure how much charge is in 
a battery. If you're not drawing any current, the potential will stay up 
at maximum until the battery is *really* low. The battery's maximum 
current diminishes long before its maximum unloaded potential does...

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>>> Interesting, how do they do that?
>>
>> You think *I* know?
> 
> It used to be that more efficient speakers in general had more unwanted 
> resonances and lumps in their frequency responses: IOW poorer fidelity.  
> I don't particularly know why but that's how it was.  Obviously the 
> designers would have overcome that if they could have, but some chose 
> low efficiency in return for better sound quality.  I don't know how 
> well they are doing now with that trade-off, it's been some years since 
> I last read any reviews.

That sounds about right.

>>> Hard to see how you could deliberately make the system less efficient 
>>> without just plonking a huge 50W resistor in series (which would 
>>> totally screw up the quality of the sound).
>>
>> And why would that be?
> 
> The answers lie in the way passive networks of electronic components 
> work and in speaker mechanics.
> 
> Firstly, the crossover network divides the signal from the amplifier to 
> the woofer and the tweeter drivers.  It must be tuned to the right 
> frequency and shape the frequency falloff curves and phase so that the 
> sound levels from both drivers are balanced without dips or humps or 
> comb-filtering at the crossover band where both drivers transmit part of 
> the signal.  It is also supposed to keep the signal phase true between 
> the two drivers over the frequency range so they operate in a unison 
> making the sound wavefront from both drivers combine and arrive at your 
> ear together.  That is fekking difficult to design, because...
> 
> Crossovers are passive networks of resistors, capacitors and inductors. 
> Networks behave much more complicatedly than isolated components because 
> everything interacts with everything else, not just its immediate 
> neighbours.  Speaker drivers are *also* R-L-C networks, so crossovers 
> must be designed with that driver's electrical properties being integral 
> to it.
> 
> In short, the whole thing is interbalanced, so if one resistor, 
> capacitor or inductor changes, everything goes out of whack -- crossover 
> frequency, frequency response, phase response, impedance response, 
> resonances and ringing -- and the speaker sounds like crap.
> 
> For predictability, a speaker and its crossover also rely on the 
> amplifier's output stage being very low impedance. Signal-wise, the 
> amplifier is near to a short-circuit, regardless of the voltage swings 
> it generates.  A speaker is a motor and when moving, it generates 
> back-EMF through its crossover.  It has mechanical inertia and wants to 
> overshoot.  It  also has natural resonances from driver suspension 
> springiness, cabinet air volume, acoustic transmission line length, 
> tuned acoustic port, etc.  That colouration is NOT part of the original 
> signal.  If the amplifier doesn't soak up that energy (absorb the 
> current), to damp the unwanted motion (overshoot and ringing) it will 
> reflect back into the network and colour the sound you hear.
> 
> So if you plonk a great big resistor in series with all that, the amp 
> can't damp unwanted speaker motion, the crossover detunes, the frequency 
> response goes lumpy, the sound goes muddy, and you think "bleccch!"  :-)

I'm sure that would be the case.

Now, what if that resistance was part of the design right from the 
beginning?

By the way... The documentation for my mum's amplifier claims that it 
contains special circuitry to cancel out the electric signals generated 
by the speakers themselves. (I have no idea whether this is special or 
whether it's something all modern amps do and they just wrote about it 
to make themselves sound cleaver...)

>>>> Hmm, I think my amplifier (nothing special) is rated at 60 W per 
>>>> channel. (IIRC, into 8 ohms at 1 kHz.)
> 
> For listening at home, the real reason for high-powered amps is not to 
> make louder noise, but for fidelity.

Hmm, isn't that what *I* said several posts ago? ;-)

>> (It's like all toasters 
>> have a special setting that transforms bread into charcole. We don't 
>> know why, but they all have it.)
> 
> <Ahem>  Just because you didn't figure it out, doesn't automatically 
> make the manufacturers into idiots.  The high setting on toasters is 
> needed to get even a _little_ colour into *crumpets*.  But, as you 
> apparently haven't toasted a crumpet before, they obviously don't exist 
> and every manufacturer out there is stupid for gratuitously making 
> toasters with a nuclear setting.
>  :-P

Wait... Surely to toast a crumpet you want a *lower* heat? (Since it's 
thicker and hence nearer to the heat source - and also you want to cook 
it slower so it cooks through completely.)

>> (I once tried connecting a line-level output to the phono input. Big 
>> mistake...)
> 
> Ow.  :-(

Sounded a bit like a metal guitar. Also made the sound come out on *all* 
input selections. o_O

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Brian Elliott wrote:

> Firstly, the crossover network divides the signal from the amplifier to 
> the woofer and the tweeter drivers.  It must be tuned to the right 
> frequency and shape the frequency falloff curves and phase so that the 
> sound levels from both drivers are balanced without dips or humps or 
> comb-filtering at the crossover band where both drivers transmit part of 
> the signal.  It is also supposed to keep the signal phase true between 
> the two drivers over the frequency range so they operate in a unison 
> making the sound wavefront from both drivers combine and arrive at your 
> ear together.  That is fekking difficult to design, because...
> 
> Crossovers are passive networks of resistors, capacitors and inductors. 
> Networks behave much more complicatedly than isolated components because 
> everything interacts with everything else, not just its immediate 
> neighbours.  Speaker drivers are *also* R-L-C networks, so crossovers 
> must be designed with that driver's electrical properties being integral 
> to it.
> 
> In short, the whole thing is interbalanced, so if one resistor, 
> capacitor or inductor changes, everything goes out of whack -- crossover 
> frequency, frequency response, phase response, impedance response, 
> resonances and ringing -- and the speaker sounds like crap.
> 
> For predictability, a speaker and its crossover also rely on the 
> amplifier's output stage being very low impedance. Signal-wise, the 
> amplifier is near to a short-circuit, regardless of the voltage swings 
> it generates.  A speaker is a motor and when moving, it generates 
> back-EMF through its crossover.  It has mechanical inertia and wants to 
> overshoot.  It  also has natural resonances from driver suspension 
> springiness, cabinet air volume, acoustic transmission line length, 
> tuned acoustic port, etc.  That colouration is NOT part of the original 
> signal.  If the amplifier doesn't soak up that energy (absorb the 
> current), to damp the unwanted motion (overshoot and ringing) it will 
> reflect back into the network and colour the sound you hear.

I read about this kind of thing in a DSP book. Damn, IIR filters sound 
so complicated! Fascinating, but... I wouldn't want to design them for a 
living.

-- 
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Orchid XP v3 wrote:
> The maximum load I saw was 40W (during the boot sequence - when
> everything turns on at once). In normal running it hovers somewhere
> below that.

Ah. Right now rendering two scenes (in a mind of testing) with max
brightness on the screen, ie. burning the CPU. I'm not consuming extreme
memory nor using wireless interfaces

groath ~ # cat /proc/acpi/battery/C1B5/state
present:                 yes
capacity state:          ok
charging state:          discharging
present rate:            2749 mA
remaining capacity:      3797 mAh
present voltage:         11671 mV

2749mA*11671mV=~32W.

> I didn't check specifically. My laptop has a very dim LCD with poor
> saturation and a horribly narrow viewing angle. No matter how you
> position your head, 50% of the display is always inverted...

For me the display was the most important part of the machine, I got
nearly what I wanted (I got 15" 1400x1050 matt display, I'd wanted 14").

> Should be noted: It's an *ancient* laptop!

Heh. I though more of an ancient (and broken) Linux distro.

> (Now *my* laptop seems to do all this in hardware, not software. Doesn't
> matter what software is running, the fan turns on and off now and then...)

Which is wise choice.

-- 
Eero "Aero" Ahonen
   http://www.zbxt.net
      aer### [at] removethiszbxtnetinvalid

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scott wrote:
> Well yeh that's kinda my point, the speaker system is designed to sound
> good.  Trying to minimise the efficiency (so that input voltage is
> higher) is not really on the list of things to do when designing a
> speaker system.
> 
> 

Yep, but practically creating a good sound leads to less efficient
speakers - afaik real Hi-Fi -speakers with over 90dB/W/m are rare stuff.

-- 
Eero "Aero" Ahonen
   http://www.zbxt.net
      aer### [at] removethiszbxtnetinvalid

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On Wed, 05 Sep 2007 07:57:09 +0200, scott wrote:

> Oh wow, that would annoy the hell out of me if I had to charge my phone
> every 24-48 hours...  Mine usually lasts about 5 days with a few texts
> and short calls per day.  I do make sure that bluetooth is turned off
> when I'm not actively using it though, maybe that makes a difference?

Probably, yes - I leave bluetooth turned on because I have a wireless 
headset for it - but I also can charge it off a USB port, so I frequently 
plug it in when I'm not using it.

But I also do a fair number of long phone calls for work on the days I 
work from home.

Jim

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> Well yeah, poor 3D, 1HD, 2x1,8GHz C2D, 15" TFT etc (the screen backlight
> is one big consumer for me, to be noted).

Yep, and expect the power consumed by the backlight to drop significantly in 
future as finally everyone switches from CCFL to LED backlights, LED 
efficiency continues to rise, and LCD technology improves (to let more light 
through).

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