Harbeth is excellent with classic rock. With hard rock and metal there are other speakers that can be rock harder though the smoother and forgiving Harbeth can actually be a good thing.
You can actually fit a SHL5 in that room though a safe choice would be the P3ESR and Compact 7ES3, if considering a Harbeth. The M30.1 is the warmest speaker in the Harbeth line with very nice vocals. However, it’s not a good all-rounder when compared to the other Harbeth speakers, in my opinion.
The ATC SCM7s are sealed boxes and will sound lightweight in the bass when compared to the fuller sounding Harbeth. Best if you can listen to both as the ATC and Harbeth sound quite different.
You can actually fit a SHL5 in that room though a safe choice would be the P3ESR and Compact 7ES3, if considering a Harbeth. The M30.1 is the warmest speaker in the Harbeth line with very nice vocals. However, it’s not a good all-rounder when compared to the other Harbeth speakers, in my opinion.
The ATC SCM7s are sealed boxes and will sound lightweight in the bass when compared to the fuller sounding Harbeth. Best if you can listen to both as the ATC and Harbeth sound quite different.