Need help with voltage for custom speaker

[Plokmijn27]

So this project is one I have been envisioning for a while, taking 2 of the same portable speaker/amplifiers and combining them to utilize the speakers and amplification of both in one custom package. I have daisy chained them together with a y splitter and enjoyed the sound but wish to put it in one package essentially.
It utilizes 4 AAA batteries in a series for around 6v (17.5mA or so). I was hoping I could utilize just one of the power supplies (battery packs) and thus use only one of the switches to operate both simultaneously. The path would essentially be split from the moment it leaves the battery compartment to both of the amplifier circuits for each speaker set.
What I am not sure of is whether or not the 6v will still be applied to both circuits evenly, and will essentially drain the batteries twice as fast (in which case I would use maybe 4AA instead of 4AAA) or whether the power pull from both circuits will be so demanding as to require double the voltage all together (12v to be split between 2 speaker circuits at 6v each)

My mind was leaning towards the latter of needing double voltage, but wanted to check before I fried 2 circuits.

 

[Harald Kapp]

What I am not sure of is whether or not the 6v will still be applied to both circuits evenly ... or whether the power pull from both circuits will be so demanding as to require double the voltage all together (12v to be split between 2 speaker circuits at 6v each)

Would you double the mains voltage only because you plug two appliances into two ports of of a wall outlet?
What you do is called a paralel circuit. Each load (amplifier) still has to and will be supplied by 6V. Doubling the voltage would destroy the amplifier.

... will essentially drain the batteries twice as fast (in which case I would use maybe 4AA instead of 4AAA) or whether the power pull from both circuits will be so demanding as to require double the voltage all together (12v to be split between 2 speaker circuits at 6v each)

Power is: P=I:V
As the voltage V is the same 6V whether you use one or two amplifiers and the power of two amplifiers is two times the power of one amplifier, total power also doubles. Therefore current consumption doubles. Bigger batteries are a good option. But not twice the voltage, see above.

 

[Plokmijn27]

Thank you that is very insightful, and will surely help with future projects. The wall outlet thing makes sense though haha didn't think of it that way.
Any like general guide as to battery life's compared by size? like would a AA generally last 1.5 or 2x as long as AAA, c battery like 3x as long? or is there no real single answer?

 

[Harald Kapp]

like would a AA generally last 1.5 or 2x as long as AAA, c battery like 3x as long? or is there no real single answer?

There is no single answer. Battery size is an indication of capacity, but it's not definite. You may find small high quality batteries with a higher capacity than cheap gig ones. You will have to find the capacity (given in mAh or Ah) from the battery manufacturer. More capacity means longer lifetime at the same load.

 

[BobK]

According to Wiki, here are the typical capacities of Alkaline batteries;

AAA 1200mAH
AA 2700mAH
C 8000mAH
D 12000mAH

So a D battery has about 10X the capacity of an AAA.

https://en.wikipedia.org/wiki/List_of_battery_sizes

Bob

 

[Plokmijn27]

Coolio, even though it's completely subjective still very helpful