I just built a speaker extension cabinet for a friend of mine. 12" cannabis rex for a Fender Super Champ XD. I'm mounting a 1/4" mono jack on the external cabinet so he can unplug the speaker out coming from the champ and use a 1/4" mono male to male cable to connect the external cabinet to the champ XD. Does the cable need to be SPEAKER cable or will a regular instrument cable work just as well? Thanks in advance.