Latest project is trying to build a home stereo sound system/soundbar. I have the speakers from this speaker system.
Having disassembled the whole thing I have 2 large speakers, a PCB connected to a 30 pin old iPhone connector, a power port, and a 3.5mm audio jack as well which connects to another PCB which has a lot of capacitors which then connects to the two speakers I pulled out of it. I don't know which of the circuits I could/should save and use in the project but I was planning to disassemble some other older stereo systems and use those as well.
The whole project is supposed to be several speakers wired together to output the same music, the input for which will come from a 3.5mm audio jack and both play the music as well as light up some addressable LEDs based on the sound input.
The first problem I have run into is that I'm not sure how to connect the speakers to the Arduino (which is what I'm currently under the impression I need to be doing in order to control the lights and the sound.) as it is my understanding that they need an amplifier circuit. This is something I've looked into but am still relatively unsure how to build so I was hoping for some input on all of this. I can post pictures of the speakers and circuitry I recovered from disassembling the stereos as well if that would help.
Speakers work on AC voltage, whereas Arduino is a DC device. If you are going to be reproducing sound, you will need to work out how you will produce an audio signal and for what purpose. If you just want to synchronize lights with sound, there are a number of light controllers that work off amplitude modulation or frequency modulation (pulse width modulation). It is also very likely that the other electronics in the system are a bandpass (or high or low pass) filter to protect the speakers from amplitude levels that would make them destroy themselves over time or cause the amplifier to clip.
The regular Arduino doesn't have a DAC, so there's no true analog output. It can make "sound" but it it's not high fidelity.
You have an analog source and the Arduino is (obviously) digital. ...You wouldn't want to do analog-to-digital conversion and then digital-to-analog conversion.
The Arduino is great for controlling the LEDs.
Yes, speakers need amplifiers. If you have multiple speakers, generally each speaker needs its own amplifier amplifier (or a pair of stereo speakers needs a stereo amplifier).
A two-way passive speaker has a woofer (for the bass) and a tweeter (for the highs) and a passive crossover network to send the low frequencies to the woofer and the highs to the tweeter. A good crossover uses inductors and capacitors. Some cheap crossovers just have a capacitor for the tweeter and the full-frequency range is sent to the woofer (although it can't reproduced the highest frequencies). A 3-way speaker adds a midrange, etc.
A two-way active speaker sometimes has a an "electronic crossover" to split the (low-power) high & low frequencies before being sent to separate amplifiers for the woofer & tweeter. A "2.1" computer speaker usually has an electronic crossover and 3 amplifiers built-in .
The board in the black diecast housing between the speakers is the amplifier/crossover I think. The proprietry
connector / ribbon cable may or may not include analog audio.
If you don't use the original housing you'll lose the bass-reflect / transmission line resonator and thus
lose a fair amount of bass response.
MarkT:
If you don't use the original housing you'll lose the bass-reflect / transmission line resonator and thus
lose a fair amount of bass response.
Why is this? I was planning to make a different housing for all the speakers but I might rethink that if there is a possibility of losing some of the bass effect.
Aode_Ward:
I was planning to make a different housing for all the speakers but I might rethink that if there is a possibility of losing some of the bass effect.
There is a large amount of design to manage the airspace of a speaker enclosure.
That does not mean that you should shy away from experimentation.
Hook your naked speakers to your stereo. Play some music. Listen to the music and form an opinion on its sound.
Then put the speakers into the original housing. Play the same music. Listen and compare the sound to the naked speaker sound.
Then put the speakers into a mocked up housing of what you intend to put them in. Play the same music. Listen and compare to the earlier sounds.
Do you hear a difference? Is if enough difference to keep the original housing? Or is the difference small enough to consider using your planned housing?
vinceherman:
There is a large amount of design to manage the airspace of a speaker enclosure.
That does not mean that you should shy away from experimentation.
Hook your naked speakers to your stereo. Play some music. Listen to the music and form an opinion on its sound.
Then put the speakers into the original housing. Play the same music. Listen and compare the sound to the naked speaker sound.
Then put the speakers into a mocked up housing of what you intend to put them in. Play the same music. Listen and compare to the earlier sounds.
Do you hear a difference? Is if enough difference to keep the original housing? Or is the difference small enough to consider using your planned housing?
That's actually a really helpful perspective, thank you.