Some sources
The author of this khutba mixed a few things there are indeed many narrations starting with a wording like (I will only list my findings on sunnah.com):
This Community will experience the swallowing up of some people by the earth, the metamorphosis of some into animals ...
or similar, but they don't agree with the later part you may find it narrated
- on the authority of Sahl ibn Sa'ad ibn Said in sunan ibn Majah (qadf might mean and being rained upon with stones)
- on the authority of Jabir in al-Bukhari's al-Adab al Mufrad,
- on the authority of 'Aisha (this narration is a bit closer to the one you've posted, but it is considered as strange narration) in Jami' at-Tirmidhi
- on the authority of Abduallah ibn 'Amr in sunan ibn Majah,
“There will be among my nation collapsing of the earth, transformations, and Qadhf.”
- on the authority of Abdullah ibn 'Omar in Jami' at-Tirmdihi (1 and 2, in sunan ibn Majah (1 and 2)
- and finally on the authority of 'Imran ibn Hussain (a version which seems close to the one you've posted):
"In this Ummah there shall be collapsing of the earth, transformation and Qadhf." A man among the Muslims said: "O Messenger of Allah! When is that?" He said: "When singing slave-girls, music, and drinking intoxicants spread."
(Jami' at-Tirmdihi, al-Albani has qualified it as Hassan -in his sahih at-Tirmidhi- according this Arabic fatwa and see also here)
there should be even shorter parts or similar narrations of the content narrated on the authority of other sahaba like ibn Mas'ud and abu Hurrairah.
It doesn't seem that imam Ahmad compiled the version of Sahl ibn Sa'id nor the one of 'Imran ibn Hussain, but he compiled the version of Abdullah ibn 'Amr (see here) and a version of Abdurrhamn ibn Sohr al-'Abdy from his father:
عبد الرحمن بن صحار العبدي عن أبيه قال قال رسول الله صلى الله عليه وسلم لا تقوم الساعة حتى يخسف بقبائل فيقال من بقي من بني فلان قال فعرفت حين قال قبائل أنها العرب لأن العجم تنسب إلى قراها
(My own Translation take it carefully)
The hour of resurrection will not occur until some tribes will experience a collapsing of the earth, and people will ask who are still existing from Tribe "X", he said (the narrator) I understood when he said Tribes that he (the prophet) meant the Arabs as the non-Arabs are referred to by their towns
Qualification of the hadith
This hadith has also a sound sanad according to al-Hakim (who compiled it), a-Dhahabi who confirmed al-Hakims qualification. Al-Haythami in his majma' az-Zawa'id added that this was also compiled by a-Tabarani, al-Bazzar and abu Ya'la and the narrators of the chain are thrustworthy. Ibn Hajjar al-'Asqalani also confirmed this in fath al-Bari.
The hadith therefore seems reliable @Uma even add in a comment a sahih narration which goes along with it.
Some further explanation
Well one could say the hadith doesn't say that singing or music instruments are haram. But as the spread of these things is a sign of the day of resurrection, which is also related to a spread of bad things the conclusion that these things are rather bad suggests itself.
On the other hand sadly it is wide spread by some scholars or khutaba' to refer laxly to books, as we see the hadith as is, is neither said by Sahl ibn Sa'ad ibn Sa'id nor does it appear in musnad Ahmad nor Jami' at-Tirmdihi by a similar wording.
