Hello again, total newb at this stuff but now that I'm addressing Audio, I'm in over my head. 
I am coming close to completing part 1 of the project discussed in this thread. The objective: synchronize lights, "boom" sounds, and a short fog burst for three "cannons" of a pirate ship. See this video, which has one of the sound modules operational.
I've since added all three sound modules, each "boom" triggers when each set of lights fires off.
In my research of mixer circuits added a basic mixer consisting of resistors only, no mixer controls needed (and that is most likely where my problem lies.) It works as expected, the three sounds fire off independently without killing the previous sound. The sound module and LED's are powered from a single 5V power source, separate from the Arduino power source.
The problem: I have integrated a cheap subwoofer amp and when used, the sounds are not separated except at super low volumes. This amp is accentuating the low noise you can't hear with the desktop amp mentioned below, and it's as if the first "boom" never ends.
Spent the last two days watching videos and reading (mostly from this forum) and I think I know what I need to do, just not sure how to do it (see below.)
I know these are low quality resources, but I don't need quality audio. I need three booms that fire as programmed, but loud (it will be outside.) I'd considered buying premade mixers/amps but this project is already was over budget for a display project.
Resources for sound
- Arduino Uno
- ISD1820 sound modules X 3
- This TPA 3116 based amp, supposedly 100 watt capability, which a lot of people seem to like.
I also have one of these, Also TPA3116 based, but haven't played with it yet. My crystal ball says I'd get the same result, the problem is in my circuit, not the amps.
Now for the likely embarrassing part, this is where my circuit is as of today.
What I have done:
- I developed this using a cheap battery powered amp from Wal-Mart. It sounds GREAT and even at full volume is exactly what I'm after. You can literally throw it in a pool, it's also waterproof. This little thing is actually awesome, just not loud enough for the application.
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Originally had the most killer ground loop, got to learn all about that. This article explains it better than any I've read in the last week.
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The subwoofer amp works with 12-24VDC. I've tried it with an 18.5v (actual voltage around 19.3) and a 12V wall wart PS, which surprisingly enough works, but the result is the same, a low loud rumble that overwrites the subsequent sounds.
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I have tested it on several passive speakers, 4 ohm and 8 ohm, result is the same (and wants to blow up the smaller ones LOL . . . )
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I have not tested it against a consumer device such as a stereo or computer. Going to try that tonight, which will tell me if it's a poor product.
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Fiddled with the controls, It appears the left one is "tone" or amount of bass boost, the right is volume, the only usable adjustment is at very low volume.
What I think I need to do:
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The "mixer" needs some work and is probably the source of the problems. I am guessing that with this amp, it's inadequate and needs reworking. As mentioned, based on several tutorials and articles, I can see they are simple circuits and just removed the complexity of pots for mix volumes (maybe I should put those back ???)
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I have no caps anywhere. The signal is likely dirty to begin with, amplifying it with a 100 watt subwoofer amp is only accentuating the problem. Caps across the audio signals, power signals? What size, ceramic or electrolytic? I have boxloads of them now LOL
Can anyone advise on what I need to do to clean up this signal and utilize this amp? Simplicity (or simpleton in my case) is key for this project. Keep in mind I'm not looking for optimum quality or perfection, I just need three "booms" that can be distinguished from each other.
