I am wondering if replacing the resistor or BJT setup I have come my Arduino Mega to my 8 Ohm 0.5W speaker would allow me to increase the volume of which the audio is being played at.
Right now the wave file is fairly quiet, as shown in my short youtube clip: Arduino Mega Audio Test
Would an Op Amp help me boost the signal at all, as I've tried to increase the volume on the wav clip, but run into clipping and distortion of the audio. Another option I was figuring was using a more powerful speaker, however I'm not sure if right now I'm just suffering from a low signal rather than quiet speaker.
You are correct, I forgot to provide that information, I'll link it it later this evening when I have the source material in front of me. I apologize for not providing that.
What I had meant is I'm not sure if the current being outputted is just very low or if the speaker itself is not very loud. Hopefully that clears that part up.
As for an active speaker, for this particular project I will not have the ability to do this, I'll either go the audio amp route, or if I have read in some older threads about someone suggesting using the the transistor to boost the gain of the signal and then put a low pass filter on the output to filter it.
Either way thank you for spending the time for typing your response, audio is a whole new kettle of fish for me in the arduino world.
Arinoth:
I am wondering if replacing the resistor or BJT setup I have come my Arduino Mega to my 8 Ohm 0.5W speaker would allow me to increase the volume of which the audio is being played at.
low-impedance = low-resistance = not suited for an Arduino output pin
How did you connect the speaker?
Directly? Or used any components between Arduino and speaker?
A speaker would be better suited if it had a higher impedance. Such like a 32 Ohm or 50 Ohm piezo speaker.
If you connect a low-impedance speaker to the Arduino OUTPUT pin, you can perhaps increase the volume when putting a 1µF capacitor between OUTPUT pin and speaker.
Or if you really want high volume: Old fashioned "active PC speakers" can be used as amplifier. But don't put a signal with DC into an amplifier input! Better use a 1µF capacitor between Arduino OUTPUT pin and amplifier input.
Bit of a bad design. You have DC in the speaker circuit.
Why in that diagram did you not swap the speaker symbol over and prevent that mess in the wiring.
Note - a speaker does not have + & - inputs specifically that just indicates what way they will push and what they will pull for a given polarity.
IT is not my specific design, merely sharing the image of someone else's design that I decided to try out.
I do know I need to add a low pass capacitor to filter out the DC in the circuit, I previously was trying to solve my initial problem of the speaker not being loud enough.
Grumpy_Mike:
NO!
A low pass filter lets DC through it, it does not block it. You need a high pass filter or a band pass filter to block DC.
Dammit, I always get the naming versus its purpose mixed up....Thanks for the helpful advice though Mike, I know I most of sounded like an idiot a few times.
That should let
(Vs - Vce)/8 ohm = 537.5mA flow
with Vs 5V and Vce = 0.7V
Watts dissipated by speaker
P=IV, = IIR = 2.3W
= V*V/R = (4.3V * 4.3V)/8 ohm = 2.3W
Watts dissipated by transistor
.5375 * .7V = 376mW.
Want it louder? Use a low Rds N-channel MOSFET instead.
I = V/R = 5V/(8 ohm + Rds)
with Rds = .025ohm, I = 623mA (can find lower even, look at AOI-514, AOI-516 at digikey.com)
Currently have some old fashion BJT and JFET transistors right now that I am going through, seeing as the quality of the sound clip I have to work with is from the 90s and ins't that high quality to begin with, as long as one can hear what is being played, which it can right now that is all I'm happy about.
The current configuration I have listed is actually louder then I need, so I'll be playing around with the resistor value, just need to add in that high pass filtering cap.
