Planning on making a music box that plays Billy Joel's "Vienna" for my significant other. I have experience with Arduino Nano and PCB design, but I am struggling with the audio part of the project. Online googling has helped me understand that two solid options for better audio quality than just beeps and boops that I see others using are the Adafruit FX Sound Board and DFPlayer (regular or pro). Would either be good with an Arduino Nano? Additionally, I can't seem to figure out whether I need to worry about power (3 vs 0.5 W) or impedance (1 vs 8) of speakers with either modules?
I also plan on powering the whole thing with a 6 V battery holder with barrel jack, which I will add to the PCB.
Music Clarity is a subjective measurement. I would suggest a MP3 player with a decent amp and speaker would do you just fine.
You can wire a DFPlayer Mini to run directly on switches.
I am not familiar with the exact audio quality of those specific boards, but you could compare specs of what files it can playback. CD quality is 44.1k sample rate, 16bit. If you can play wave files of that spec it should sound pretty good. MP3 of lower quality will start to sound grainy etc. As for impedance, I think that is a requirement based on the power of your amplifier. You can buy a small audio amplifier chip, which would probably be a good idea. This way you can experiment with impedance of your speaker vs the power of the signal to get the best sound quality for your music box. Here's a link to an audio amplifier :
good luck, I hope this helps!
The sound quality from the DFPlayer, or similar, should be fine. You can get noise from the power supply and batteries tend to be "quiet" except for any noise that gets into the power supply from the Arduino.
I'm going to hit you with some math...
Impedance (or resistance) is "the resistance to current flow". Ohm's Law defines the relationship between Voltage, resistance, and current as Current (Amps) = Voltage / Resistance.
Most speakers are 4 or 8 Ohms. Piezo transducers/speakers are higher impedance but they are basically tweeters so no-good for voice or music.
With lower impedance (and the same voltage) you get more current and more power (wattage).
The "basic" power formula is Power = Voltage x Current.
With that and Ohm's Law we can derive another handy formula: Power = Voltage squared / Resistance.
With 6VDC and a "regular" amplifier you can get 6V peak-to-peak. That's 3V peak or 2.1V RMS. That's the theoretical maximum, but there will be some "loss" through the amplifier.
2.1V RMS into 4-Ohms gives you 1.1 Watt and that's most you can expect with a 6V power supply.
That should be plenty for a music box.
A bridge amplifier (which drives both speaker terminals in opposite directions, with no ground to the speaker) you can get double the voltage for 4 times the wattage.
...If the amplifier doesn't have a volume control, you'll probably need one between the audio board and the amplifier to adjust the volume and to prevent over-driving the amp into distortion,
I power my Music Box and JukeBox (which use the DFR MP3 Player module) with 3 x AA batteries.
6V to the barrel jack will be inadequate; you’ll need 9V.
So which part would give the "clarity:" MP3 vs WAV and other file types, amplification which an Arduino Nano cannot do or the speaker wattage and impedance?
Yes I plan on trying that or directly with Arduino, just to see which I prefer.
So does the DFP player not have an integrated amp? Would I have to connect Arduino to DFP player to amp for best sound quality?
The Arduino is a general purpose microprocessor, you would need something dedicated to sound processing. There codecs etc that would do what you want but they are not the easiest to use.
From your description this will be a small and personal thing, I think the best place to put your money is in something that is capable of doing what you want such as a DFP player, some have there own dedicated audio electronics such as this one: DFPlayer Mini Mp3 Player - DFRobot Wiki They will sound OK but that is a subjective measurement. For those use to high end systems there rating will be much different then those that use small radios. The best choice is the one you like. Remember as time progresses you can upgrade the audio and improve the sound a lot starting with the speaker.
WAV is a raw data file and can be higher quality sound, mp3 is a compression audio file and is "lossy" and lower quality, however mp3 can still sound pretty good, but if you want higher quality go for higher resolution WAV