Re: Which uses less power

Bill Powell <bill@anarchists.org> wrote:

I had thought the phone's speaker would be MUCH MORE power hungry though,
than casting the audio to the bluetooth speaker - but one respondent said
it was NOT more efficient (while another said it was more efficient).

Depends on whether your phone supports BLE (Bluetooth Low Energy) or the
older traditional BT.  BLE will consume as much power as BT, but sends
in bursts.  Between the bursts the BLE radio is at idle/sleep power
level.  However, there are high-efficiency speakers that can be used in
the phone, and other factors depend how much power the speakers consume,
like volume level.  Ear buds and headsets don't need to use nearly as
much power to generate the same volume as the speakers since they are in
or right atop your ears.  There are a lot of variances in the components
used for the speakers, in the headset, if BLE or BT is used, and even
the capacity of the battery (a lower capacity battery will die faster
under the same load).

As others pointed out, you should measure the difference in battery drop
(starting from a full charge) while testing how much the battery level
drops between when using the speaker, and when using the BT headset.
You could use an app to monitor battery usage by app, like whatever
you're using the play the podcast, or the main battery's drop in power
level.  I would test for, at least, an hour in each mode (speakers only,
and BT/BLE headset only), and probably repeat the test, at least, 5
times to get an average reading.  Recharge to 100% before each test to
start at a known capacity in the phone's battery.  For the BT/BLE
headset, make sure those are also charged 100% before each test when
using them for audio output.  Testing and measuring will let you know
for sure.  You could use an app to measure the battery drop after each
test, and gauge where the power is most consumed, or just watch the
battery level indicator for a rough estimate.

My non-exhaustive research shows that with newer components, and using
BLE with the headseat, and with high-efficiency speakers, the speakers
will draw the same, or maybe a tiny more, than the BLE headset.  Higher
audio volume in the speakers means more power consumed by the phone's
battery, just like higher volume in the headset means more power
consumption on the headset's battery. 

I was in the camp that speakers used more power than BLE headsets, but
the more I read the more they can be [nearly] equal in power consumption
if the latest components are used in the design.  Actual measurement is
more accurate rather than guessing based on specs which can be wildly
exaggerated.  If you have internal SATA-3 drives, HDD or SSD, or even
m.2 NVM3 SSDs in your computer, have you ever reached the theoretical
and marketed 6 Gbps transfer rate, even for burst transfer mode versus
sustained transfer mode?  Marketing cannot be trusted to supply accurate
specifications.