Advice on speakers for project kit - tiny ones

[dabbler]

Hi all. I have started making desk and table clocks, mainly to add a little extra to my pen-making sales. I want to add something other than just more analogue clock faces to my small range and decided on this:
http://dx.com/p/m1-1-5-lcd-mp3-player-module-w-clock-usb-tf-silver-dc-5v-151454#.UxUeIvmSySo
I was tempted by the sound options as well as time function. My plan is to mount this in a timber frame/box/pen holder.

The kit didn't even come with a chinglish how-to sheet so I'm flying in the dark. My electronics is dated and basic but I've worked in IT from the days when you fitted your own ICs and made your own cables so I'm okay for wielding a hot soldering iron. I haven't decided on power options yet but I'm not concerned about that just yet. One buyer/reviewer of this kit suggests "Amplifier has plenty of power (I'd estimate it around 2W per channel) to drive small speakers.".

So the question is, what advice can you give me on speakers ? I imagined something small and internal for the early projects.
And what happens long term if speakers are under or over rated for the kit's output specs (whatever they are) ?

I'm okay with the suck and see approach but a starting point would be handy.

[RayG]

Start with the mechanicals, do a google image search for miniature speakers and look for something that fits the mechanical contraints of the design.. my first guess would be laptop internal speakers might be suitable, I think I've even seen on with that connector..

Don't be too fussed by impedance mismatches, this is not going to be hi-fi audio :D

Ray

PS https://www.google.com.au/search?q=miniature+speakers&source=lnms&tbm=isch&sa=X&ei=oZcWU-esLom5iQeKu4GYBg&sqi=2&ved=0CAcQ_AUoAQ&biw=1750&bih=953

[mike48]

My suggestion is to use the largest speaker that will physically fit into your project, as miniature speakers may sound tinny.
The reviewer may have meant "small" to be 4 inch or so.

But, you can buy as small as 25mm dia speakers from suppliers such as Jaycar and Altronics inter alia, if that is what you had in mind.
I have used 25mm mylar speakers as internal speakers for coms receivers, and the audio result is not ideal, even for speech.

After you decide on a size, take your electronics unit into a supplier shop and make a final decision on the speaker size based on availability, and then ask about possible header connectors to match your PCB speaker connectors, otherwise you may have to solder the speaker leads to the PCB.

Speakers do have max level ratings, but normally if you overload them they sound loud and very distorted, and you run to turn down, turn off or disconnect.
You can burn out a speaker coil, but it requires a severe overload with a low impedance source amp, and your scenario is probably not like this.
The average power of an audio device playing music at loud listening levels in a normal room is surprisingly low, and highly unlikely to cause coil burnout damage.
If the speaker max power rating is higher than your amplifier's output power, then it is normally of no consequence whatsoever (provided of course we aren't talking about very large speakers requiring a minimum drive power) .

It is unlikely that your proposed setup will damage or burn out any speaker.
Experiment with speakers from old junked equipment, TVs, radios, PCs etc, but use identical speakers for left and right channels.

And as Ray says, don't worry too much about impedance mismatch between speaker and amplifier.

mike

[dabbler]

Thanks for the suggestions Ray and Mike. They pretty much fit my ideas and plans if I flew blind.

This build is a bit of experiment and will probably be given to a family member for testing it's usefulness so failure is actually a valid option in this case.

All projects are on hold at the moment though - an injured family member means I am visiting hospital every mealtime to make sure she's fed.