As a long time owner of SHL5 (7 years) and currently SHL5+ for about 5 years now, the SHL5+ is the brightest sounding speaker in the Harbeth line to me. I’ve listened to the P3ESR, C7ES3, M30, M30.1, M30.2, M40 and M40.1. I actually find the rest of the Harbeth speakers to sound too warm for my preference, particularly the M30 series. Hence the SHL5+ gets my vote.
I actually find the SHL5+ to sound warm, dull and lacklustre when matched with several amps. I swapped several amps on the SHL5+ in an attempt to make it sound brighter at the top and more lively and dynamic.
While waiting for a response from Arafiq on the comparison between the M30.1 and SHL5+, here’s my take. M30.1 sounds more intimate, warmer and fuller in the midrange with a rounder and slightly rolled off treble. To me the 30.1 has a warmer sound but it sounds more forward than the SHL5+. The sound leaps out more from a silent background with the 30.1. The SHL5+ sounds more even and balanced.
30.1 sounds great with vocals and intimate music, not so much with rock and larger scale music. The sound is too controlled and lacks airiness in the treble. SHL5+ is more versatile and a better all rounder. Bass on the SHL5+ is much better than 30.1 as expected. There’s heft and wallop, and the bass sounds more defined too. Moving from SHL5+ to 30.1 you will feel a chunk of bass missing.
I guess this will apply too when switching from SHL5 to 40.1 or 40.2.
In the end, it’s a matter of preference as usual. The differences are all relative. The SHL5+ can still fit in a 12’ x 15’ room.