So.. I have made a couple of boxes for testing...
Aluminium 120mm x 120mm x 60mm approx project boxes
Box 1 is an amplifier
Its has a 2 channel class d amplifier board, a voltage cut off board, a makita power tool usb charge adaptor glued on so it can run of 18v power tool battery
in line fuse to protect battery
phono inputs, speakon and spring terminals for speakers
power switch and led and fuse blown led
Box 2 is the same aluminium box but with a 4 inch car speaker in it
speakon connector and spring terminals
I am an AV engineer and these will come in handy for test fault finding
the question.... the car speaker sounds naff in such a small box
not so bothered about the lack off bass but the massive peak around 1khz
I was planning to run a power resistor in series with the speaker anyway to offer it some protection from high power 2kw plus amplifiers
could I reverse an bandpass filter in parallel with the speaker instead of in series with another resistor to attenuate the nasty peak at 1khz?
the driver is 4 ohms nominal haven't measured it but I'd bet its a lot higher at 1khz! based on 4 ohms I guess I would want something like a 1mh inductor and a 40 uf cap? but it would probably need a bit of trial and error !
Is there anything wrong with this design
I don't want the test box to be an amplifier destroyer! That creates more work this is meant to simplify little fault finding jobs!!
Its never gonna sound great but this sounds worse than the makita site radio!
Aluminium 120mm x 120mm x 60mm approx project boxes
Box 1 is an amplifier
Its has a 2 channel class d amplifier board, a voltage cut off board, a makita power tool usb charge adaptor glued on so it can run of 18v power tool battery
in line fuse to protect battery
phono inputs, speakon and spring terminals for speakers
power switch and led and fuse blown led
Box 2 is the same aluminium box but with a 4 inch car speaker in it
speakon connector and spring terminals
I am an AV engineer and these will come in handy for test fault finding
the question.... the car speaker sounds naff in such a small box
not so bothered about the lack off bass but the massive peak around 1khz
I was planning to run a power resistor in series with the speaker anyway to offer it some protection from high power 2kw plus amplifiers
could I reverse an bandpass filter in parallel with the speaker instead of in series with another resistor to attenuate the nasty peak at 1khz?
the driver is 4 ohms nominal haven't measured it but I'd bet its a lot higher at 1khz! based on 4 ohms I guess I would want something like a 1mh inductor and a 40 uf cap? but it would probably need a bit of trial and error !
Is there anything wrong with this design
I don't want the test box to be an amplifier destroyer! That creates more work this is meant to simplify little fault finding jobs!!
Its never gonna sound great but this sounds worse than the makita site radio!
