skullshogun

So, this may be a long read.. be prepared.

I gutted an old amp I had to create a talk-box. Thats not the problem Im having however. I disconnected the actual speaker in order to attach a different one to the amp-box to do it... So i was left with a slightly larger useable speaker. I have wire, soulder, souldering gun, everything I need basically...

My idea is to make a smaller more compact housing for the speaker, a wooden box essentially that is just slimmer then an amp. This box will have on the side two jacks. One 1/8 monojack to plug in MP3 players to, and One 1/4 jack for plugging in a guitar or other electrical instrument. The idea is to have a 3 position switch (middle off) to toggle between either Jack depending on what I want to use. The problem Im having is with the power. Obviously hooking up an MP3 Player isnt going to give much juice to the 5 inch speaker... (since it doesnt have an external power source). So I bought a 4 AA battery holder (i have seriously TONs of them lying around, someone just gave em to me for no reason...) and basically.. I just need to know how to hook it up so that the AA battery holder helps power the speaker without taking away the quality...
I tried the "retard" method and just hooked up the battery holder as many ways as possible to the switch/wires... all it did was diminish the sound and make the speaker go kinda crazy, lol.

Im not an expert at electronics as you can tell, But I just started getting into doing random little things like this...
My dad has some experience in this area, but Hes hardly ever at home when I have time.. So i ask, who here can help me and give me decent directions on how to hook up the AA battery holder in a way to help power the speaker (mind you, I have otyher materials, i only listed the ones I was THINKING of using, im willing to get more).
And also, I want to boost the signal INTERNALLY, that is to say, I dont want an external signal booster or anything. Something on the inside that will help power the speaker.
Help would be much appreciate as im stumped...

audioguru

A speaker needs an enclosure that is big enough so that it can produce bass frequencies. Your enclosure might be too small.
If your speaker is cheap then it won't produce bass frequencies anyway and a small box will make it worse. It will sound "boomy".

A speaker is driven by a power amplifier, not a battery.
A power amplifier is powered by a battery but your battery has only 6V when it is new and 4V when it is old.

With only 6V the power output from an LM386 power amplifier IC into an 8 ohm speaker is only 0.2W which is very low power.
When the battery has dropped to 4V then the power to the speaker will be only 0.063W which is extremely low power.

__________________
Uncle $crooge

skullshogun

hmm... well what kind of batteries would I need to amplify the speaker enough then?

(aside from the fact that i need a power amplifier..)
this little project seems to be taking alot more then previous anticipated.. however, I want it done! ><

audioguru

First figure out how much power you need into the speaker. An LM386 power amplifier is one of the smallest and weakest so its output is only 0.45W with a brand new 9V battery. A cheap clock radio is louder.

There are more than 100 amplifier ICs for cars. Most produce 14W into a 4 ohm speaker or 8W into an 8 ohm speaker with a 13.8V supply.

The jack for the electric guitar will need a preamp circuit that has a very high input impedance.
The MP3 input and the output of the guitar preamp will need a mixer circuit.

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Uncle $crooge