What speed to use???In the olden days the industry only 'used' the high speed descent..About M83 in the DC8 and B707(Boeing advocated the use of Banking to 45 to expedite the nose drop through the Horizon with poss 'G'..
Thence the indisrty ,about the time of Aloha'questioned the 'High' speed in all cases.So the general dictum went out to evaluate before diving.With a sudden Immediate depression one was to suspect structural failure and check the Doors indication for the assessment-If strucural ,slow down or at least use the present speed,to avoid ascerbating the problem..Slow with gear down produced nearly the same rate 6000+
With the 'alt warning horn'this was a subtle failure and the cabin was above 10000',try to recontrol it,if no joy,start down fast to'MEET' the cabin alt,thence level off at the 'new' cruise alt..If your lucky no masks will deploy and you've lots of Supplemental available..
Food for thought,when your doing your A/p selections..
Cheers
On the A320 it was quite a \'slow\' affair starting down