measuring speakers

Hi there
when I want to measure a woofer with a SPL meter ,and use variable tone generated by my computer , I disconnect the two other drivers in that speaker cabinet , but what do I do with the other cabinet after I disconnect it. Put a load on that line with a resistor??? don't want to blow up my Rega brio
If there's no signal in that other amp channel, it should not matter if or what is connected to it.

BTW, consider getting REW software for this.

Brio amp has cd input ,volume control ,and 1 stereo output
That's it, very simple and no way to switch off one channel
BTW thanks for the answ and I'm having a look at the REW software
But if the computer is only outputting one channel, the other one is silent and its load will not matter.

Just a question of unplugging one of the stereo lines from the computer feeding into the Brio.------> thanks, grey matter missing upstairs at 68
best wishes