Why is Talkie Library so quiet.

Hi. I am a beginner to Arduino and I have a very simple question, i recently found the Talkie Library and I tried it and it worked pretty well but it is much quieter than a regular noise code, why is this?

Connect an audio amplifier and speaker to the output pin, and make it as loud as you like.

You will probably need a low pass filter, say 10K /0.022 uF and a DC blocking capacitor (10-100 uF) between the Arduino and the amp.

OK. Thank you so much.

Good question virtuos1. And I’m still waiting for an answer too. If those digital pins can crank out 5 volts peak-to-peak, why is it not louder with a small 8 Ohm speaker?

Because it uses a PWM signal to do the job of a digital to analogue converter which has only eight bits of dynamic range. This is scaled across all possible outputs the LPC decoder can produce. Speech waveforms are very spikey and eight bits is not much of a dynamic range. So you either go for some distortion or scaling back, it’s a compromise. This low volume is the result of that comprise.

There is a vast difference between the peak of a waveform and perceived loudness. You might think the two are linked, they are but not as much as you would hope. This is why projects like trying to light up a warning light when the noise level in a canteen is deemed too much have failed.

Right… The average of a voice or music waveform is about 1/10th of the peak so it’s MUCH quieter than the constant square-wave tone() output. And a square wave is louder than a sine wave.

The Arduino can’t directly drive an 8-Ohm speaker. (You can but you shouldn’t and you won’t get 5V.)

The “absolute maximum” current from an Arduino I/O pin is 40mA. From Ohm’s Law, that works-out to 125-Ohms minimum.

You can get more than 40mA out but you are exceeding the specs, the voltage will drop, the Arduino will overheat (at least internally) and “bad things” can happen.

Excellent. Lots of info there. Thanks gents.

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