Bi amplification, active filtering, dsp etc

hi all,
i have this ambition, if any one can comment and help pliz:
i have a vim1 (and a bunch of other arm linux boards). i also have 2 tone boards, and enough analog in amplifiers and passive speakers. i want to build an audio system which is bi or triamplified, uses active frequency separation in the digital domain, and eventually allow a few audio tweaking like parametric equalization, multiband dynamic expansion , sub harmonic synthesis etc…

To begin with, how can i connect my 2 toneboards to a single vim1, preferably over i2s wires for each ?
@Gouwa @hyphop @Stefan

u have 3 diff connection variants (u can use all type at same time)

do you mean that i can connect one tb over spdif and the other over i2s ?

yes !!

VIM  => SPDIF OUT => TB1 
    \=>  I2S OUT  => TB2

ok , i ve seen pin 13 for spdif out to tb1, and pins 29,31,32 for i2s to tb2, right ?

YES :wink: YES YES YES YES !!! ;))

ok! and by spdif, do we mean pin13 of vim to pin 13 of tb or spdif rca in of tb ?

for the power supply, i think of using the +5v on the pin1 or pin2 of the toneboards, and provided by external power suppy (which could also power the vim).
Once wiresv wil be all sorted out and the system boots without any magic smoke, then comes the question of what to do on the software side for…
1- sending audio simultaneously to spdif and i2s pins of vim and from linux (alsa)…
2- apply different processings to each audio flow before sending them to tb1 and 2

nb: my vim1 will run no bulky gui but good old plain text ssh text session from the network

@hyphop please explain how to use I2S with the TB. According to the schematic the GPIO I2S goes only to the ‘I2S Ext’ connector J9. The ‘8 Channels Ext’ connector J3 has I2S to the XMOS, but so far as I know it would need a modified firmware to make use of this in any way.

@ravelo again judging by the schematic, pins 13, 15 and 16 from VIM to TB and configure it to be SPDIF out, then coax between the RCA SPDIF connectors. Pins 15 and 16 switch the SPDIF routing, but I’m not sure how this appears on the VIM software. For whatever reason there doesn’t seem to be a way to route the SPDIF from the VIM into the DAC of the TB that’s connected to it - I guess it’s expected to use the USB connection on pins 3 & 4, but in your use case that’s no good as the clocks will drift out of sync over time. I don’t know enough about the VIM hardware to know if the I2S and SPDIF use the same clock or not - it may even depend on which end of the I2S is the clock master. Is the VIM I2S capable of TDM like the Beaglebone, or just I2S like the Raspberry Pi?

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