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Open Source, hardware and software, 3D-printed planar magnetic headphones powered by a Raspberry Pico (github.com)

submitted 1 year ago* (last edited 1 year ago) by MazonnaCara89@lemmy.ml to c/opensource@lemmy.ml

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[-] avidamoeba@lemmy.ca 2 points 1 year ago* (last edited 1 year ago)

I just checked the latest firmware of their DAC and it has a bit of distortion when driven at the default settings. There's now an app that allows to adjust the pre gain to eliminate it but then the final output is not very loud. I think this is the reason why they keep the pre gain as high by default. There isn't a lot of distortion but if you know where to pay attention, you can hear small pops here and there. I'm driving mine with a set of Topping gear. The output is Topping E30 II and that can drive them loud enough without distortion. I've dialed in their default PEQ into PulseEffects's EQ. To be clear, these cans cannot be used without PEQ. That's part of the trick making a physically imprecise driver to sound good. If you want to use alternate DAC/amplification, you have to replicate the PEQ somewhere along the signal chain.

[-] priapus@sh.itjust.works 2 points 1 year ago

Good to know that it's not to hard to recreate the EQ. I'm already using EasyEffects convolver effect for my current headphones. I was planning to give the included DAC/AMP a try, but I'd definitely prefer to use my own Schiit stack in the long run. Are you able to share the PEQ you are using?

[-] avidamoeba@lemmy.ca 1 points 1 year ago* (last edited 1 year ago)

You can scoop em up straight from the source:

...
        .f1  = { PEAKING,    {0},    38.5, -21.0,  1.4  },
        .f2  = { PEAKING,    {0},    60,    -6.7,  0.5  },
        .f3  = { LOWSHELF,   {0},    105,    5.5,  0.71 },
        .f4  = { PEAKING,    {0},    280,   -3.5,  1.1  },
        .f5  = { PEAKING,    {0},    350,   -1.6,  6.0  },
        .f6  = { PEAKING,    {0},    425,    7.8,  1.3  },
        .f7  = { PEAKING,    {0},    500,   -2.0,  7.0  },
        .f8  = { PEAKING,    {0},    690,   -5.5,  3.0  },
        .f9  = { PEAKING,    {0},   1000,   -2.2,  5.0  },
        .f10 = { PEAKING,    {0},   1530,   -4.0,  2.5  },
        .f11 = { PEAKING,    {0},   2250,    6.0,  2.0  },
        .f12 = { PEAKING,    {0},   3430,  -12.2,  2.0  },
        .f13 = { PEAKING,    {0},   4800,    4.0,  2.0  },
        .f14 = { PEAKING,    {0},   6200,  -15.0,  3.0  },
        .f15 = { HIGHSHELF,  {0},  12000,   -6.0,  0.71 }
...

https://github.com/ploopyco/headphones/blob/1e6896f918383854ec5a74e860dd7ed58671cae5/firmware/code/configuration_manager.c#L55