Hey all,
I’m working on a modification of a Bluetooth headset; I’m building a Bluetooth speakerphone. I was inspired by a similar project I saw on the internet http://www.youtube.com/watch?v=ziQvBBZniZo , however I am having a volume issue with the replacement speaker; I can’t hear anything unless I hold it up to my head. I got in touch with the guy who built the project that I took inspiration from, all he would tell me was that he used a bigger speaker and no amplifier circuit; he would not get more specific.

I have 0.98v showing on my multi meter from the Bluetooth speaker leads.
My question is this, what kind of speaker do I need to put on this thing to have it be audible from a few feet away? I only have 3 volts to play with so the LM386 amplifier circuit I built doesn’t have enough power to function and therefore is not an option.
I would like to just replace the speaker, but I do not have enough knowledge on the matter to make an educated guess.

Any assistance would be greatly appreciated!

Thanks
-ash

 

1V into a 32 ohm earphone produces a power of only 0.03W.
You need to amplify the current so that an 8 ohm speaker will produce a power of 0.125W.

But 1V is 2.828V peak to peak and an amplifier needs to have some extra power supply voltage to work. A TDA2822M amplifier IC has an output power of 0.125W into 8 ohms at clipping with a 4V supply.

 

Thank you very much for the response, it is much appreciated!
Luckily I have engineered a usable power source that fits in the enclosure and can provide 6v, I got everything working on the old amp IC, so now I’m going to order the TDA2822M and give that a try.