Is there a difference in listening to music in Sefirah if it is with instruments or not?
The Minhag is to not listen to music (recorded or live) during Sefriah days. Some are lenient to listen to music which is only sung by the mouth (without instruments).
However, many contemporary Poskim say this is the same as music. Certainly, some of these recordings sound very professional and contravenes the original purpose of the custom.
Although the Shulchan Aruch (Orach Chayim 493) and Shulchan Aruch Admur Hazaken only mention not to dance during the Sefirah days and do not mention anything about music, the Alter Rebbe does mention Simchos Yeseiros and many Poskim clearly mention music.
ולהעיר שבלקט יושר כתב למנוע אפילו בנוגע לשירה בפה – ודיינו להתיר בזה, ולא במוקלט, עכ״פ כשהוא בגדר ״שמחות יתירות״.