building my own portable speakers need help!

[callumirvine]

normal portable speakers just arnt cutting it for me anymore and are too expensive for decent ones, so ive decided to utilise my old car 6x9s (vibe slick 69.3 **broken link removed** all the details on them are if needed) with a mini portable amp such as (**broken link removed**)
im fairly confident with wiring it all up, but would that work correctly? if not are there any other portable/battery powered amps that could be used
and dont say its just easier to buy a portbale speaker because i want the project
thanks
-callum

 

[Nigel Goodwin]

An LM386 is a puny little amplifier, think tiny portabl;e radio power - is that all you're looking for?.

 

[audioguru]

6 x 9 car speakers rely on the huge volume of the trunk (boot?) of the car as their enclosure to produce some bass. With normal-size enclosures then there is no bass.
The LM386 is designed for 8 ohm speakers and your 4 ohm speakers overload it so with a 9V supply, the output is only 0.3W and the heating is high at 0.8W.

My computer speakers are only 3 inches in diameter but have flexible rubber surrounds and huge magnets. The enclosures are the correct size for them (but are small) and the amplifiers produce 3.5W each. They produce good bass down to about 60Hz.

 

[callumirvine]

okay so maybe i didnt read into the amplifier as much as i should have, but is the principle correct?
if i could find another portable amplifer that would even power one of the speakers would it work? plus any suggestions?

 

[audioguru]

30 years ago I made portable speakers for the beach. I used 3" stereo satellite speakers and a 4" woofer. I used amp ICs that are not made anymore.
Today there are more than 100 amp ICs made for car radios but they have a very high current all the time which is not suitable for a portable application.
National Semi has many extremely tiny amp ICs made for notebook computers but their output power is too low and they are too small to work with.

But National Semi has the LM4950T amp IC that is in a TO-220 case with 9 pins. Its idle current is low enough for a portable amplifier.
With a 12V supply its stereo output into 4 ohm speakers is 3W per channel or 1.8W per channel into 8 ohm speakers.

You should find some speakers that work well with a small enclosure.