In the guitar world, we know there are certain speakers that are stiffer and color (read as distort) less than others. For example, the Celestion Greenback is well-known for coloring early and offering speaker distortion easily to your tone. Are there any hard and fast rules in terms of speaker coloration and bass rigs? Do 10 inch speakers break up quicker than 15 inch ones? Will a 4x10 break up less than a 2x10? If you were running a 120 watt tube head, what two cabs would you use together to maximize headroom and volume?