Hi... I have successfully built a circuit with an lm386n-4 with a 1/2 watt, 8ohm speaker. I'm powering it with 6v.

The loudness is ok - but i would like it to be more - something that I could put in a car and have it loud enough to overcome road noise.

I can get a pair of 8 ohm, 50 watt woofers - and wondered if they would work as a replacement for the 1/2 watt speaker.

I've read about building a crossover circuit - but thought I would take things 1 step at a time...

For now, I just want to get a decent sound.

 

Ur plan is not possible.
LM386 is very small amp. When u make the two 50W 8ohm woofers parallel, then it becomes 100W 4 ohm. Ur amplifier at 6V supply is not even 0.5W.
U need minimum 100W amplifier to drive the two 50W woofers in parallel with 4 ohm impedance.

 

LM386 is not a car amp. It’s a very small low voltage amp used in earlier 1989 portable tape players & AM radios. Don’t connect any woofers to it just connect a 4ohms speaker to it.

If you powering from a car then you have around 12-13.5 V voltage with a good ampere range. So better make an AMP that runs with 12V.Something like starting with TDA & TA numbers like TDA 2005 (bridge) .Will make a descent sound, if you need a preamp you can add that too & make a complete amp for car audio. For this amp you can connect woofers, tweeters etc.But not for LM386…..

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Gayan

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Thanks for the feedback - it was very helpful...

By chance, can you recommend any project/circuit examples I could review/make?

 

No you don't!
A TDA2005 and many other car radio bridged amp ICs have an output power of 14Watts at clipping with a 4 ohm load and a 13.8V supply. Then each 8 ohm woofer gets 7W which is a little less than a "200Whats" car radio that has four 14W channels.

The little LM386 has an output power at clipping of only 0.2W with a 6V supply and an 8 ohm speaker. Its power into 4 ohms is the same. Less than a cheap clock radio.

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Uncle $crooge

 

Thanks again... Can you also recommend any project example I can study/replicate?

 

Look here.

http://www.sweb.cz/ds01/tda2005.pdf

 

The TDA2005 has 20Watts into a 4 ohm load when its supply voltage is overcharging a car battery at 14.4V and when its volume control is turned up way too high so it has an awful sounding 10% distortion.
Look at the graph of distortion vs power. It clips at about 15W with a 14.4V supply and has less power when the supply is 13.8V.

The newer TDA7240A has only 7 pins and has the same performance.

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Uncle $crooge