Sound controlled circuit - adjustable?

I'm a bit of a noob - I've only done a couple of projects and I have a lot to learn.

I have bought the components for this project: http://www.simple-electronics.com/2011/10/sound-controlled-circuit.html . Basically an electret microphone that will trigger (in my case) 30 leds.

I have three questions before I break out the soldering iron...

Will this circuit make the load (30 leds) turn off and on with enough sensitivity to make it look like it's responding to music? (I know you've heard this one a fair few times)

Is there a simple mod I can include to change the sensitivity of the trigger? Like if it was quiet I could have a pot to turn it up and if loud, down.

If you're curious, I'm embedding the leds in a jacket for a NYE festival.

Any help would be highly appreciated.

It needs a 470R

colin55 said:

It needs a 470R
View attachment 59679

Click to expand...

Hi Colin, thanks for your help!

Will that affect the sensitivity?

no. . .

colin55 said:

no. . .

Click to expand...

I will buy the resistor tomorrow along with a couple of other parts - what will it do?

The circuit is too simple.
The horrible biasing of the first transistor causes the sensitivity to depend on its amount of current gain:
1) With a very low current gain then a loud sound will turn it on which will turn on the load.
2) With a medium current gain then it will be very sensitive.
3) With a high current gain and/or a high temperature then the first transistor will be saturated all the time and the load will be turned on all the time.

EDIT: The circuit can drive a few LEDs, each with its own current-limiting resistor. 30 LEDs need more power than this circuit provides.