I have need to control a number of actions (lights, fog etc ) for a stage production (not difficult and I am able to do this) but I must start an Mp3 music file at precisely the same time. The music needs to quit loud (to fill a small theater loud) and of high quality. Looking at what is available, I find many mp3 SD card readers but very wimpy amplifiers for the Arduino. I have looked at stand alone Mp3 capable stereo systems but have found none that simply start playing on power up (like a simple relay could do). Since all I need to do is start the player (sound being preset) does anyone have any ideas as to where to begin?
You need to look at “disco “ equipment where the music can be stopped started .
The Arduino is suitable for turning it off /on , but I would not use it for storing or playing it .
You’ll need a big amp too - 100-200watt
You find wimpy amplifiers because in most cases they use small speakers and everything is powered by only 5 volts. I don't see why you can't use some of the specialized boards like DFPlayer Mini MP3 Player by connecting it to a more powerful amplifier from TPA series for example. For the amplifier you will also need a power supply.
Since the physical data on the theater and other needed things are missing I will take a SWAG and say For this project I suggest you look at some maybe used commercial gear, in the several hundred watt range or more. A pair of TPA3256s appropriately assembled with the correct speakers may be able to do what you want. These should to be line powered as batteries will be very large and expensive. You would need at least a set of 12" speakers, 18" would be better. Sound is never better then what the speaker system can provide. The appropriate MP3 player or one controlled properly could do what you want.
Your theater should have a sound system, or you can rent one. Or you might be able to get-by with a good home stereo setup. That's a different topic.
The DFplayer or any of the "audio shields" should be fine with the Arduino. These things handle all of the audio, including reading the file and the digital-to-analog conversion. The Arduino is just a controller. Although, if you get "digital noise" (usually whine) in the analog output the audio board may need its own-separate power supply.
Note that MP3 is lossy compression. Data is thrown-away to make a smaller file and that can degrade sound quality. It's "smart" and it tries to throw-away little details that you can't hear anyway. It can be very-good a higher bitrates (1) and it can often sound identical to the uncompressed original, but I would avoid it if you don't need the compression (and if you have a non-lossy file available). Regular WAV files are uncompressed and FLAC is lossless compression.
(1) bitrate (kbps = kilobits per second) is related to file size and playing time. There are 8-bits in a byte so you can divide by 8 to get the file size kilobytes per second (ignoring any space for embedded artwork). A higher bitrate means a bigger file. Less data is thrown-away so you can potentially get higher quality.
So what I am hearing is a DFplayer will take the music file from an SD card controlled by the Arduino board. The output is then fed through a regular analog amplifier to my speakers. I can preset the amplifier prior for volume etc which is fine for my purposes. I then start the music using my sketch which also controls the external lights, fog etc Correct?
Thank You That makes things a lot easier and clearer.
And... If you have a DMX lighting controller you could trigger the Arduino via DMX, but that's another layer of hardware & software, and I assume you're under a time constraint for a show so you'll want to keep it simple.
One note about the DF Player: I have experienced small and unpredictable delays playing tracks. These delays were <0.5 seconds, but different all the time. That made it impossible to start a few of them at the exact same time, same enough to make the resulting music sound good.
This may or may not be a problem for your application, just something to be aware of when you need very precise synchronisation.
There are multiple versions of the boards out there, I don't know if it is unique to my boards. Never had a project since where I needed so precise timing, in most projects this delay just doesn't matter.
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