Guru
Joined: 05/03/2018
Location: NetherlandsPosts: 5690
| Posted: 07:50am 16 Dec 2022 |
Hi Tom,
You are in a difficult situation. And I am not sure what I can do to help you, except experiment.
In essence the loudspeaker needs to pressurize air, and the air pressure wavefront travels to your ear. To build a wavefront it needs to displace air, and is doing so by moving the front surface. A speaker can only displace a volume that is equal to it's surface area multiplied by the movement of that surface.
If you look at a speaker with a diameter of 1.5cm, it needs 10x the surface movement of a speaker with diameter 4.5 cm. Or.. with similar movement the 5cm speaker is 10x as loud. So your small speaker has a disadvantage. YTou need to drive it really hard to get some audio out of it.
For computer games sounds (at least the vintage games) distortion is not really an issue (it even gives a charme to the game) so you can drive the speakers really hard.
The circuit you build (without the inductor) is designed to give low distortion, you can use it to play WAV's directly ripped from a CD, and it sounds good. But it does not drive the speaker to the max to avoid distortion.
I have no datasheet on the speaker you use, but if it is the same 16 ohm BUZZER discussed earlier, you would need to change the 47 to 33 or even 22 ohm (which will impact battery life seriously) to drive it to the optimum. But still, you would not get into distortion.
Can you share the spec of the speaker, or confirm it is still the same BUZZER.
Then we can look and see if we can work on a better solution, driven from 3.7V...4.V
Acoustics... Yeah....
When a wavefront is traveling to you , and the inverse wavefront (reflected by whatever PCB/walls/hands) also, you do not get optimal sound. That is "black art" (not really) that companies tie their name to. That is why you see "BOSE" on laptops, that have the same problem. Small speakers, tight space, how to get the best sound quality.
Volhout
P.S. if you know you are going to have a small speaker, low frequencies are typically not output well, you may also gain a bit by making the game sounds higher frequency. Just tune the whole melody 1 octave up.
Edited 2022-12-16 17:54 by Volhout