Timeline for Loudspeaker volume issue
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 12, 2018 at 3:00 | history | tweeted | twitter.com/StackElectronix/status/1050581884718202880 | ||
| Oct 11, 2018 at 12:42 | answer | added | bharath | timeline score: 2 | |
| Oct 11, 2018 at 12:22 | comment | added | bharath | @glen_geek: But the motorboating did not end: After certain input volume increase the effect is recurring, though at a much higher volume. I remembered your suggestion about power supply weakness being a cause. I checked and again, I was using the same wires. I removed the wires from the amp and directly connected the amp to the power supply rail pins. Motorboating solved. Increase is now smooth all the way to maximum on the input signal. It is really wonderful to hear the same speaker sound so clear and loud, all because of a change of wires! My thanks to you and jonk. | |
| Oct 11, 2018 at 12:19 | comment | added | bharath | @glen_geek: I finally found the issue. It is the wires. I used wires from a generic ribbonstrip of 40 wires (male-to-female, Dupont type). I would cut off one end and solder them on to the speaker and use the other end to connect to the amp. For some unknown serendipitous reason, I measured the resistance of a wire, from speaker to amp with my multimeter. The resistance was 80 ohms. The other wire was also roughly the same. So, I was running the sound for a 4Ohm speaker through an additional resistance of 160 Ohms. Replacing these with solid core wires got the volume to acceptable levels. | |
| Oct 8, 2018 at 6:37 | comment | added | bharath | @jonk: Hi, Thanks for responding! Probably hidden away in the detail of the question, but the input source is no longer the micro-controller, but a headphone out from my phone/laptop. DC blocking: I was assuming the module already had caps on it for this, but will re-check this again. | |
| Oct 8, 2018 at 6:35 | comment | added | bharath | @glen_geek: Hi, Thanks for responding! the module may have caps on it to do this, but I will do it and report back. | |
| Oct 7, 2018 at 21:29 | comment | added | jonk | What is the input source and why isn't there any DC blocking at the input side? If it is the MCU, don't you imagine there is a DC bias to it? (I have NO IDEA what you are actually doing from the MCU side. But perhaps I missged something you wrote, in skimming quickly. Easier to just ask.) | |
| Oct 7, 2018 at 15:18 | comment | added | glen_geek | clipping/motorcycle noise? This is perhaps audio motorboating. Your circuits show no power supply capacitors. A large value (greater than 100uF) should be added very close to the chip, from DC supply (Vcc) to Gnd. | |
| Oct 7, 2018 at 14:38 | history | asked | bharath | CC BY-SA 4.0 |