I have the 2Ci, on their original metal stands (the ones with the T shaped foot). The quote below is taken from
https://www.stereophile.com/content/vandersteen-2c-loudspeaker-measurements
I drive them through other vintage, Harman-Kardon Citation 17s pre-amp and 16As amp, and original Monster cable - the ones the size of a garden hose. So I run tweeter +1 and midrange -1 as suggested below.
"I found a touch of lift in the high treble (tweeter set to +1dB) to be necessary to counteract the speaker's slight lack of off-axis air; this has to be balanced, however, against exaggerating the excess of HF energy above 10kHz. Though this might then be thought to leave the midrange a little depressed, I nevertheless found -1dB on the midrange control to give the optimal balance between the need for sufficient high-midrange energy and not to unduly emphasize the speaker's uneven response in the same region. This will be different for every listening environment and system, however. "
https://www.stereophile.com/content/vandersteen-2c-loudspeaker-measurements
I drive them through other vintage, Harman-Kardon Citation 17s pre-amp and 16As amp, and original Monster cable - the ones the size of a garden hose. So I run tweeter +1 and midrange -1 as suggested below.
"I found a touch of lift in the high treble (tweeter set to +1dB) to be necessary to counteract the speaker's slight lack of off-axis air; this has to be balanced, however, against exaggerating the excess of HF energy above 10kHz. Though this might then be thought to leave the midrange a little depressed, I nevertheless found -1dB on the midrange control to give the optimal balance between the need for sufficient high-midrange energy and not to unduly emphasize the speaker's uneven response in the same region. This will be different for every listening environment and system, however. "