2 speakers for Ruby serial/parallel?

[Mann]

I've got two 3" 0.5w 8ohm speakers and I tested the Ruby with just
one - sounded ok/tinny (not boxed) but not very loud.
What would the benefits with two mini speakers connected
serial vs. parallel?

(I'm not expecting miracles - just a small amp for my 7 years old son...)

[petemoore]

Two 8 ohm loads parallel= 4 ohms....louder/more amp load.
 One eight ohm speaker compared to two 8 ohm wired in parallel [4 ohm load]= Louder, and more load on the amp. Follow [don't overload it by wiring too low an ohmage speaker follow the ohmage specs for output on the amp.
 Two 8 ohm in series=16 ohm...less load on amp, less loud output.

[smoguzbenjamin]

An LM386N-3 should be able to handle a 4ohm load fine. I've done it and it hasn't given me any trouble whatsoever. I did however fry a 386N-1 with a 4ohm speaker though :?

[Mark Hammer]

You can't make a 3" 1/2W speaker turn into a fire-breathing 12" Celestion, but you'd be surprised how much more tolerable a suitable box can make even poor speakers.  For a case, consider one of the plastic chassis at Radio Shack that will accommodate both speakers with a bit of depth behind them.  

Because the boxes are plastic and will have somewhat flexible walls at that size, you will need to provide some acoustic damping to avoid a boxey honking rattling sound.  I've never done it, but I would suggest picking up a square of "fun foam" at the local crafts/hobby shop.  That's the stuff your son probably uses at school for making shapes they stick on the window, etc., It's cheap and easily cut with scissors.  Cut out a swatch to cover the rear wall of the chassi and use contact cement or hot glue to secure it.  Similarly, if you can find a way to do it, damp down the front panel so that the speakers are resting against it.  That will avoid the speakers mechanically coupling to the box and turning the chassis walls into transducers that resonate at only a few annoyingly unmusical frequencies.

A decent box will allow more of the below-500hz content to actual turn into something real.  If you want to go superdeluxe, make a stereo unit that can provide instant music with a cassette or CD player.

Since 7 year-olds have a propensity to leave things on and forget to turn them off (how'd you know I have one of my own? :lol: ), you might consider using either a 4-pack, 6-pack or 9-pack of AA cells for power.  This will give you much greater battery life at the same voltage (9v), and more power at a higher voltage (12v).  I hasten to point out that the 386-1 does not take kindly to being run at 12v into a 4-ohm load though.

[Mann]

I actually made drawings yesterday of a box I'm going to build over the weekend. I've got lots of different leftover wood from ny sauna/bathroom
(and guitarbuilding too...) renovation  so a bottle of wine (or two, or three)
and we'll see...
I tested differenet speaker combinations and come to the conclusion that
one 3" 8 ohm speaker is the best solution at this case.
Got to think about the battery consumption though.