i have no idea what a "console-only" version of hdspmixer would actually do, but perhaps you could consider the following as inspiration also (which uses amixer(1) to control the hdsp matrix mixer from the cmd line):

#!/bin/bash

AMIXER="amixer -q"
CARD="-c 1"

if [ x$1 = xon ] ; then
    gain=32768
    verb="route"
else
    gain=0
    verb="mute"
fi

shift;

#input_source : 0-25  (physical channels),
#               26-51 (software playback)
#output_source : 0-25 (physical channels),
#               26-27 (line out)

case $1 in
    play)
    for chn in $(seq 26 51);do
        $AMIXER $CARD cset numid=5 $chn,$(($chn-26)),$gain
    done
    ;;

    thru)
    for input in $(seq 0 25);do
        for output in $(seq 0 25); do
        if [ $input != $output ]; then
            $AMIXER $CARD cset numid=5 $input,$output,$gain
        fi
        done
    done
    ;;

    thru12)
    $AMIXER $CARD cset numid=5 0,0,$gain
    $AMIXER $CARD cset numid=5 1,1,$gain
    ;;

    mon)
    for chn in $(seq 26 51);do
        if [ $(($chn % 2)) -eq 0 ] ; then
        $AMIXER $CARD cset numid=5 $chn,26,$gain
        else
        $AMIXER $CARD cset numid=5 $chn,27,$gain
        fi
    done
    ;;

    all)
    for input in $(seq 0 51); do
        for output in $(seq 0 27); do
        echo -n "."
        if [ $gain = 0 -o $input != $output ]; then
            $AMIXER $CARD cset numid=5 $input,$output,$gain
        fi
        done
        echo
    done
    ;;

    off)
    for input in $(seq 0 51); do
        for output in $(seq 0 27); do
        echo -n "."
        if [ $gain = 0 -o $input != $output ]; then
            $AMIXER $CARD cset numid=5 $input,$output,$gain
        fi
        done
        echo
    done
    ;;
esac