Help In Building A Homemade Speaker

eddychamoun

Hello LebGeeks,
I wanna build a homemade speaker using speakers from an old radio so on the back of the speaker there was written the specs such as 3.2 ohm and 4 watt now my question is : what is the voltage specified for this speaker ?
I've did some research about it and I've found this formula : Volt = Square Root of (watt x ohm) is it right ?!
So after using this formula I've found that the Voltage specified for this speaker is about 3.5 V . Now I've plugged in the speaker to the headphones port and then to the USB port of my Laptop because the USB Port is about 5 V but the speaker didn't work .
Any suggestions would be appreciated .

mesa177

Can you please provide a picture of the specifications' plate? Or perhaps the model number of the speaker?

PS: The equation for the voltage is right.

eddychamoun

mesa177 wroteCan you please provide a picture of the specifications' plate? Or perhaps the model number of the speaker?

PS: The equation for the voltage is right.

This is a picture of what I want to do with the speakers

So as you see in this image I would like to connect the speakers in series rather than parallel .
Any suggestions to improve this project ?

mesa177

eddychamoun wroteThis is a picture of what I want to do with the speakers http://i49.tinypic.com/34i4nxx.png
So as you see in this image I would like to connect the speakers in series rather than parallel .
Any suggestions to improve this project ?

Eddy, when I asked for the specifications' plate pic, it was to identify the properties of the speaker (I know you already gave the resistance rating and the power rating, but you might have read the nominal values instead of the real values).

As for connecting the speakers in series, I would advise against that since if one of the speakers were to defect, then the whole system shuts down.

eddychamoun

hmm there wasn't any real values only those values that i've said before so I don't know the nominal values of the speaker ! And for the connection between the speakers , if I connected the speakers in parallel that might decrease the total ohm value then it decrease the sound of the speakers . And that's might be another problem !
So for now the problems are :
- How much of Voltage should I feed the speakers with ?
- Should I connect them in series or parallel or series/parallel ?
And as I said before after calculating the specific voltage for one speaker the result was 3.5 V and I've connected the speaker to the usb port of my laptop which should give 5 V but the speaker didn't worked .And I'm sure that the speaker is working .