A lot of good responses here which clearly show the members who posted have experience with Harbeth speakers.
I’ll keep it short and cut to the chase. I’m referring to the previous generation Harbeth line since I don’t have experience with the current new XD version. Firstly, if you find C7ES3 to have too much energy in the treble, I presume they sound bright to your ears. I would not dispute with that as everyone hears differently. If you find the C7ES3 to sound bright at the top, the SHL5+ will be even worse as it is leaner sounding and brighter in comparison to the warmer C7ES3. The M30.1 or M30.2 may be a better option for your listening preferences.
Secondly, SHL5+ will not sound good if placed close to the front wall in my experience. They have about 3’ clear space from the front wall in my room. 2.5’ is still acceptable but closer to 2’ the airiness is compromised and the sound is slightly congested in the middle. Side wall placement is not as critical as they can go nearer to the side walls with toe-in. They still need about 1.5’ to 2’ from the side wall though.
In summary, the SHL5+ can still work in the room but the real question is whether the sound is to your preference. The M30.1 might be a better fit for the room, size - wise. Personally I prefer the SHL5+ over M30.1 as I find it more balanced across various music genres. The M30 series sound too smooth and laid back for my tastes. In the end it depends on what you are seeking and the best is to hear all options and decide for yourself.
I’ll keep it short and cut to the chase. I’m referring to the previous generation Harbeth line since I don’t have experience with the current new XD version. Firstly, if you find C7ES3 to have too much energy in the treble, I presume they sound bright to your ears. I would not dispute with that as everyone hears differently. If you find the C7ES3 to sound bright at the top, the SHL5+ will be even worse as it is leaner sounding and brighter in comparison to the warmer C7ES3. The M30.1 or M30.2 may be a better option for your listening preferences.
Secondly, SHL5+ will not sound good if placed close to the front wall in my experience. They have about 3’ clear space from the front wall in my room. 2.5’ is still acceptable but closer to 2’ the airiness is compromised and the sound is slightly congested in the middle. Side wall placement is not as critical as they can go nearer to the side walls with toe-in. They still need about 1.5’ to 2’ from the side wall though.
In summary, the SHL5+ can still work in the room but the real question is whether the sound is to your preference. The M30.1 might be a better fit for the room, size - wise. Personally I prefer the SHL5+ over M30.1 as I find it more balanced across various music genres. The M30 series sound too smooth and laid back for my tastes. In the end it depends on what you are seeking and the best is to hear all options and decide for yourself.