Hi,

I have a circuit that outputs a 72Hz square wave connected to an 8ohm 0.25watt loudspeaker.

It is so quiet.

I dont know much about sound or speakers, but i want to increase the pitch of the tone and the volume.

Am i correct in think that i need to increase the frequency to increase the tone? And i need to increase the amps to increase the volume?

Is there a way to output 2 or more pulses for each pulse of the original 72Hz circuit?

For example, the first circuit drives the second circuit?

How would i go about achieving this?

Thanks

 

A frequency doubler would produce a 144Hz signal from the 72Hz input.
A phase-locked loop circuit can produce almost any frequency in phase with the input signal.

 

The efficiency of a loudspeaker falls off at low frequencies,such as 72Hz.
Higher frequencies will be reproduced more effectively,so you probably wouldn't need to increase the power output.

How about using the 72Hz signal to turn a 400Hz oscillator on & off?----might sound a bit funny,though!

Or,if you want to get a bit more sophisticated,it is possible to synchronise an astable multivibrator on a higher frequency,using your original 72 Hz frequency.

Or,use your 72Hz square wave to charge a capacitor,which supplies a control voltage to a 400Hz oscillator turning it on?

 

A speaker that is rated at only 0.25W is very cheap and is very small. Cheap small speakers can barely produce frequencies less than about 200Hz.

Your cheap little speaker might be producing only the harmonics of the 72Hz squarewave that are at 216Hz, 360Hz and a few higher frequencies.

If you use a speaker that has more quality (is more expensive), is larger, has a much higher power rating and is in an enclosure that is designed for its spec's then the 72Hz sound will be much louder. But a squarewave sounds like a buzzer.

The pitch of a sound is its frequency. Low pitch= low frequency and high pitch= high frequency.