Can using a ipod on a louder volume drain the battery quicker.

February 17, 2017 9:55 AM

Was thinking if I listen to my Ipod louder will it drain the battery quicker than if I listen to it at a quiter volume? However, I'm just using an Ipod as an example. I guess the same could be asked of any electrical item; say a TV set will it use more power if watched at a louder volume.
posted by maxmix to Science & Nature (11 answers total)

At a very minute level yes but not something that you'd notice.
posted by Candleman at 10:05 AM on February 17, 2017

There's a well defined, logarithmic relationship between output power and perceived loudness. Loudness increases by 3 dB with every doubling in power; a 10 dB increase in volume (which is perceived as twice as loud) requires a 10X increase in power.

That said, it's hard to say what the rest of the system power usage is, so doubling the power consumption of the audio amplifier still might not present much of an increased drain when expressed as a percentage.
posted by fedward at 10:14 AM on February 17, 2017

Using the screen, followed by wireless communications, followed by the processor will be using most of the battery on your mobile device. Powering the audio jack will be minor, as Candleman notes.

I've put a kill a watt on a home audio receiver in the past, and it consumed basically the same amount of power while idle as while playing music, which I found quite surprising. Of course, it's not operating in a battery powered situation.
posted by Phredward at 10:14 AM on February 17, 2017

I've put a kill a watt on a home audio receiver in the past, and it consumed basically the same amount of power while idle as while playing music, which I found quite surprising. Of course, it's not operating in a battery powered situation.

Without getting bogged down too much: that's how most solid state amplifiers work. The amplification circuit runs at constant power all the time (that's actually what solid state refers to). The volume knob doesn't turn amplification up, it decreases attenuation applied to the input signal. (This simplifies things a bit; as they say on twitter, don't @ me).

Recent improvements in digital signal processing have resulted in new output circuit designs, so in the case of a phone it's likely volume is adjusted digitally and output power is indeed a function of loudness.
posted by fedward at 10:28 AM on February 17, 2017

fedward vs Phredward, a fight to the death
posted by fedward at 10:29 AM on February 17, 2017

Uh, fedward there's a fair amount of misinfo in there, but I'll just say this: solid state doesn't mean constant power, it means the amplifier is using semiconductor circuits instead of vacuum tubes. Are you thinking of Class A/B/C/D amps?

Back to the question, electronic sound production chains are extremely efficicient, and you won't see much power consumption change based on volume level. It is dwarved by the power supply, CPU and display consumption. Turn the brightness way down if you want to save power.
posted by intermod at 10:49 AM on February 17, 2017

I was trying not to get too far into the weeds with Class A/AB/etc so I (over)simplified. The amps I've built and the amps I've taken apart have indeed had constant-state power circuits. But yes, there's way more than what I wrote and I was trying to acknowledge being sloppy without talking about preamp circuits and switching power supplies and so on.
posted by fedward at 11:33 AM on February 17, 2017

The speaker in your earphones is driven by an electromagnet, so yeah, more volume, more juice going through the magnet.

But...as has been said elsewhere, compared to the energy consumed by other functions of your device, the amount of juice pulled by the speaker is going to be pretty trivial.
posted by Kid Charlemagne at 11:39 AM on February 17, 2017

Also: solid state doesn't mean constant power, it means the amplifier is using semiconductor circuits instead of vacuum tubes.

I knew this, and this was a bad edit on my part I completely failed to see. Thanks for pointing it out. There's a difference between simplifying and just being wrong, and I was wrong there.
posted by fedward at 11:53 AM on February 17, 2017

Here's just a very rough estimate. Assume the maximum audio output power is 60 milliwatts. I think that's reasonable. The ipod touch battery capacity is 1000 milliamp-hours at 3.7 volts, which is 3700 milliwatt-hours.

The audio play time is 40 hours. So in 40 hours the audio output consumes 60 x 40 = 2400 milliwatt-hours. So out of the total battery capacity of 3700 milliwatt-hours, 2400 of them are going to the earbuds. That's a pretty big chunk of the total power budget, about 65%.

From this very rough analysis, it seems you would get a noticeably longer play time at half volume than full volume. But just a few notches of volume difference might not be as noticeable.
posted by JackFlash at 9:05 PM on February 17, 2017

Wait, everyone says "no", but then the last answer says "yes"; we can't leave it like this!
posted by at at 9:20 PM on February 20, 2017